Keep a simple-value list observable without treating it as a child ViewModel.

Co-authored-by: Cursor <cursoragent@cursor.com>

fx/src/main/java/de/neitzel/fx/view/BindingList.java

@@ -0,0 +1,62 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.injection.ApplicationContext;
+import javafx.beans.DefaultProperty;
+import javafx.scene.Parent;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * The list of binding elements declared inside {@code fx:define}.
+ * <p>
+ * The list is not a scene-graph child. FXML adds each {@link DirectBinding} or
+ * {@link ComputedBinding} child to {@link #getElements()}.
+ */
+@DefaultProperty("elements")
+public class BindingList {
+
+    private final List<Object> elements = new ArrayList<>();
+
+    /**
+     * Creates a list and registers it with the load in progress.
+     */
+    public BindingList() {
+        LoadSession.register(this);
+    }
+
+    /**
+     * Returns the binding elements in this list.
+     * <p>
+     * FXML appends child elements to the returned list. A child is a {@link DirectBinding} or a
+     * {@link ComputedBinding}.
+     *
+     * @return the mutable list of binding elements
+     */
+    public List<Object> getElements() {
+        return elements;
+    }
+
+    /**
+     * Applies every binding element in this list.
+     *
+     * @param namespace  objects addressed by {@code fx:id}
+     * @param viewModel  the ViewModel for this View
+     * @param controller the Controller for this View, or {@code null} when the document names none
+     * @param root       the scene-graph root of this View
+     * @param context    the container that creates a named Converter
+     */
+    void apply(Map<String, Object> namespace, ViewModel viewModel, Object controller, Parent root,
+               ApplicationContext context) {
+        for (Object element : elements) {
+            if (element instanceof DirectBinding directBinding) {
+                DirectBindingApplier.apply(namespace, viewModel, directBinding, context);
+            } else if (element instanceof ComputedBinding computedBinding) {
+                ComputedBindingApplier.apply(namespace, viewModel, controller, root, computedBinding);
+            } else {
+                throw new IllegalArgumentException("Not a binding element: " + element);
+            }
+        }
+    }
+}

fx/src/main/java/de/neitzel/fx/view/ComputedBinding.java

@@ -0,0 +1,70 @@
+package de.neitzel.fx.view;
+
+/**
+ * A Computed binding declared in FXML.
+ * <p>
+ * The element names the control by {@code fx:id}, the control property, and a no-argument
+ * method on the Controller. The method value uses a {@code #method} prefix, such as
+ * {@code #workingAge}. The method may read the Controller's fields. Its result is written to
+ * the control property. The method does not write the Model.
+ */
+public class ComputedBinding {
+
+    private String control;
+    private String property;
+    private String method;
+
+    /**
+     * Sets the {@code fx:id} of the control.
+     *
+     * @param control the control id
+     */
+    public void setControl(String control) {
+        this.control = control;
+    }
+
+    /**
+     * Sets the control property name, such as {@code text}.
+     *
+     * @param property the property name
+     */
+    public void setProperty(String property) {
+        this.property = property;
+    }
+
+    /**
+     * Sets the Controller method. A {@code #method} value names a no-argument method.
+     *
+     * @param method the method value, such as {@code #workingAge}
+     */
+    public void setMethod(String method) {
+        this.method = method;
+    }
+
+    /**
+     * Returns the {@code fx:id} of the control.
+     *
+     * @return the control id
+     */
+    public String getControl() {
+        return control;
+    }
+
+    /**
+     * Returns the control property name.
+     *
+     * @return the property name
+     */
+    public String getProperty() {
+        return property;
+    }
+
+    /**
+     * Returns the Controller method value.
+     *
+     * @return the method value, such as {@code #workingAge}
+     */
+    public String getMethod() {
+        return method;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/ComputedBindingApplier.java

@@ -0,0 +1,147 @@
+package de.neitzel.fx.view;
+
+import javafx.beans.property.Property;
+import javafx.beans.value.ChangeListener;
+import javafx.beans.value.ObservableValue;
+import javafx.scene.Node;
+import javafx.scene.Parent;
+import javafx.scene.control.Control;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+
+/**
+ * Writes a Controller method result into one control property and keeps it current.
+ */
+final class ComputedBindingApplier {
+
+    private ComputedBindingApplier() {
+    }
+
+    /**
+     * Applies one Computed binding.
+     * <p>
+     * Calls the Controller method and writes the result to the control property. The method
+     * runs again when a JavaFX property changes on a control in this View or on this View's
+     * ViewModel, other than the target property. Writing the target does not call the method
+     * again, so the write does not loop. The Model is not written.
+     *
+     * @param namespace  objects addressed by {@code fx:id}
+     * @param viewModel  the ViewModel for this View
+     * @param controller the Controller for this View
+     * @param root       the scene-graph root of this View
+     * @param binding    the declaration
+     */
+    static void apply(
+            Map<String, Object> namespace,
+            ViewModel viewModel,
+            Object controller,
+            Parent root,
+            ComputedBinding binding) {
+        Object control = namespace.get(binding.getControl());
+        if (control == null) {
+            throw new IllegalArgumentException("No control \"" + binding.getControl() + "\"");
+        }
+        Property<Object> target = controlProperty(control, binding.getProperty());
+        Runnable refresh = refresh(controller, binding.getMethod(), target);
+        refresh.run();
+        watchControls(root, target, refresh);
+        viewModel.addAttributeListener((observable, oldValue, newValue) -> refresh.run());
+    }
+
+    private static Runnable refresh(Object controller, String methodValue, Property<Object> target) {
+        boolean[] running = {false};
+        return () -> {
+            if (running[0]) {
+                return;
+            }
+            running[0] = true;
+            try {
+                target.setValue(invoke(controller, methodValue));
+            } finally {
+                running[0] = false;
+            }
+        };
+    }
+
+    private static void watchControls(Parent root, Property<?> target, Runnable refresh) {
+        watchNode(root, target, refresh);
+    }
+
+    private static void watchNode(Node node, Property<?> target, Runnable refresh) {
+        if (node instanceof Control control) {
+            watchProperties(control, target, refresh);
+        }
+        if (node instanceof Parent parent) {
+            for (Node child : parent.getChildrenUnmodifiable()) {
+                watchNode(child, target, refresh);
+            }
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void watchProperties(Object bean, Property<?> target, Runnable refresh) {
+        ChangeListener<Object> listener = (observable, oldValue, newValue) -> refresh.run();
+        for (Method method : bean.getClass().getMethods()) {
+            if (method.getParameterCount() != 0 || !method.getName().endsWith("Property")) {
+                continue;
+            }
+            if (!ObservableValue.class.isAssignableFrom(method.getReturnType())) {
+                continue;
+            }
+            Object value = readProperty(bean, method);
+            if (value instanceof ObservableValue<?> observable && observable != target) {
+                ((ObservableValue<Object>) observable).addListener(listener);
+            }
+        }
+    }
+
+    private static Object readProperty(Object bean, Method method) {
+        try {
+            return method.invoke(bean);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not read property " + method.getName(), failure);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private static Property<Object> controlProperty(Object control, String propertyName) {
+        String methodName = propertyName + "Property";
+        try {
+            Method method = control.getClass().getMethod(methodName);
+            Object value = method.invoke(control);
+            if (!(value instanceof Property<?> property)) {
+                throw new IllegalArgumentException(methodName + " did not return a property");
+            }
+            return (Property<Object>) property;
+        } catch (NoSuchMethodException failure) {
+            throw new IllegalArgumentException(
+                    "No property " + propertyName + " on " + control.getClass().getName(), failure);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not read property " + propertyName, failure);
+        }
+    }
+
+    private static Object invoke(Object controller, String methodValue) {
+        if (controller == null) {
+            throw new IllegalArgumentException("No controller for " + methodValue);
+        }
+        String name = methodName(methodValue);
+        try {
+            Method method = controller.getClass().getMethod(name);
+            return method.invoke(controller);
+        } catch (NoSuchMethodException failure) {
+            throw new IllegalArgumentException("No computed method \"" + methodValue + "\"", failure);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not call " + methodValue, failure);
+        }
+    }
+
+    private static String methodName(String methodValue) {
+        if (methodValue != null && methodValue.startsWith("#")) {
+            return methodValue.substring(1);
+        }
+        return methodValue;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/Converter.java

@@ -0,0 +1,35 @@
+package de.neitzel.fx.view;
+
+/**
+ * The developer-written translation between a Direct binding's Attribute value and its control value.
+ * <p>
+ * The container constructs the class and injects its services. {@link #toControlValue(Object)} turns
+ * the Attribute value into the control value. {@link #toAttributeValue(Object)} turns the control
+ * value into the Attribute value and runs only when the Direct binding runs toward the Model.
+ * A toward-view binding does not call the reverse method, so a converter used only toward the View
+ * can leave it unimplemented. When a method cannot produce a value, it throws a runtime exception.
+ * The binding then keeps the previous value.
+ */
+public interface Converter {
+
+    /**
+     * Turns the Attribute value into the control value.
+     *
+     * @param attributeValue the current Attribute value, which may be null
+     * @return the value written to the control
+     */
+    Object toControlValue(Object attributeValue);
+
+    /**
+     * Turns the control value into the Attribute value.
+     * <p>
+     * Called only when the Direct binding runs toward the Model ({@code model} or {@code both}).
+     * A toward-view binding does not require this method.
+     *
+     * @param controlValue the current control value
+     * @return the value written to the Attribute
+     */
+    default Object toAttributeValue(Object controlValue) {
+        throw new UnsupportedOperationException("no reverse conversion for " + controlValue);
+    }
+}

fx/src/main/java/de/neitzel/fx/view/DirectBinding.java

@@ -0,0 +1,110 @@
+package de.neitzel.fx.view;
+
+/**
+ * A Direct binding declared in FXML.
+ * <p>
+ * The element names the control by {@code fx:id}, the control property, the Path, and the
+ * direction, and an optional Converter class. A Path of one name is that Attribute of this
+ * View's ViewModel. Further names step into the ViewModel of a Complex attribute, and the
+ * direction applies to the last name. When that last name is complex, the control receives the
+ * Model instance behind the ViewModel. Direction values are {@code view}, {@code model}, and
+ * {@code both}. The Converter value is the class name. The container creates that class.
+ */
+public class DirectBinding {
+
+    private String control;
+    private String property;
+    private String path;
+    private String direction;
+    private String converter;
+
+    /**
+     * Sets the {@code fx:id} of the control.
+     *
+     * @param control the control id
+     */
+    public void setControl(String control) {
+        this.control = control;
+    }
+
+    /**
+     * Sets the control property name, such as {@code text}.
+     *
+     * @param property the property name
+     */
+    public void setProperty(String property) {
+        this.property = property;
+    }
+
+    /**
+     * Sets the Path. One name is an Attribute of this View's ViewModel.
+     *
+     * @param path the path
+     */
+    public void setPath(String path) {
+        this.path = path;
+    }
+
+    /**
+     * Sets the direction. Accepted values are {@code view}, {@code model}, and {@code both}.
+     *
+     * @param direction the direction value
+     */
+    public void setDirection(String direction) {
+        this.direction = direction;
+    }
+
+    /**
+     * Sets the Converter class name. The container creates that class.
+     *
+     * @param converter the converter class name, or {@code null} when values pass through
+     */
+    public void setConverter(String converter) {
+        this.converter = converter;
+    }
+
+    /**
+     * Returns the {@code fx:id} of the control.
+     *
+     * @return the control id
+     */
+    public String getControl() {
+        return control;
+    }
+
+    /**
+     * Returns the control property name.
+     *
+     * @return the property name
+     */
+    public String getProperty() {
+        return property;
+    }
+
+    /**
+     * Returns the Path.
+     *
+     * @return the path
+     */
+    public String getPath() {
+        return path;
+    }
+
+    /**
+     * Returns the direction value.
+     *
+     * @return {@code view}, {@code model}, or {@code both}
+     */
+    public String getDirection() {
+        return direction;
+    }
+
+    /**
+     * Returns the Converter class name.
+     *
+     * @return the class name, or {@code null} when values pass through
+     */
+    public String getConverter() {
+        return converter;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/DirectBindingApplier.java

@@ -0,0 +1,315 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.injection.ApplicationContext;
+import javafx.beans.property.Property;
+import javafx.collections.ObservableList;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Map;
+
+/**
+ * Connects one Direct binding to a control property and a ViewModel Attribute.
+ */
+final class DirectBindingApplier {
+
+    private DirectBindingApplier() {
+    }
+
+    /**
+     * Applies one Direct binding.
+     *
+     * @param namespace objects addressed by {@code fx:id}
+     * @param viewModel the ViewModel for this View
+     * @param binding   the declaration
+     * @param context   the container that creates a named Converter
+     */
+    static void apply(Map<String, Object> namespace, ViewModel viewModel, DirectBinding binding,
+                      ApplicationContext context) {
+        Object control = namespace.get(binding.getControl());
+        if (control == null) {
+            throw new IllegalArgumentException("No control \"" + binding.getControl() + "\"");
+        }
+        Resolved resolved = resolve(viewModel, binding.getPath());
+        if (resolved == null) {
+            return;
+        }
+        Property<?> controlProperty = controlProperty(control, binding.getProperty());
+        Property<?> attribute = resolved.attribute;
+        if (resolved.complex) {
+            switch (binding.getDirection()) {
+                case "both" -> alignBothComplex(controlProperty, attribute);
+                case "view" -> alignTowardViewComplex(controlProperty, attribute);
+                case "model" -> alignTowardModelComplex(controlProperty, attribute);
+                default -> throw new IllegalArgumentException("Not a direction: " + binding.getDirection());
+            }
+            return;
+        }
+        if (attribute.getValue() instanceof ObservableList<?> values) {
+            assignList(controlProperty, values);
+            return;
+        }
+        String converterName = binding.getConverter();
+        if (converterName == null || converterName.isEmpty()) {
+            alignPlain(controlProperty, attribute, binding.getDirection());
+            return;
+        }
+        Converter converter = converter(context, converterName);
+        switch (binding.getDirection()) {
+            case "both" -> alignConverted(
+                    controlProperty, attribute, converter, viewModel, binding.getPath(), true, true);
+            case "view" -> alignConverted(
+                    controlProperty, attribute, converter, viewModel, binding.getPath(), true, false);
+            case "model" -> alignConverted(
+                    controlProperty, attribute, converter, viewModel, binding.getPath(), false, true);
+            default -> throw new IllegalArgumentException("Not a direction: " + binding.getDirection());
+        }
+    }
+
+    private static void alignPlain(Property<?> controlProperty, Property<?> attribute, String direction) {
+        switch (direction) {
+            case "both" -> alignBoth(controlProperty, attribute);
+            case "view" -> alignTowardView(controlProperty, attribute);
+            case "model" -> alignTowardModel(controlProperty, attribute);
+            default -> throw new IllegalArgumentException("Not a direction: " + direction);
+        }
+    }
+
+    /**
+     * The Attribute a Path names, and whether that Attribute is complex.
+     */
+    private static final class Resolved {
+        private final Property<?> attribute;
+        private final boolean complex;
+
+        private Resolved(Property<?> attribute, boolean complex) {
+            this.attribute = attribute;
+            this.complex = complex;
+        }
+    }
+
+    /**
+     * Follows a Path to the Attribute it names.
+     * <p>
+     * One name is an Attribute of {@code viewModel}. Each earlier name steps into the ViewModel
+     * held by that Complex attribute. A null Complex attribute along the Path leaves the binding
+     * unapplied.
+     *
+     * @param viewModel the ViewModel for this View
+     * @param path      the Path
+     * @return the Attribute for the last name, or {@code null} when a Complex attribute
+     *         along the Path is null
+     */
+    private static Resolved resolve(ViewModel viewModel, String path) {
+        String[] names = path.split("\\.", -1);
+        ViewModel current = viewModel;
+        for (int index = 0; index < names.length - 1; index++) {
+            String name = names[index];
+            Property<?> step = current.property(name);
+            if (step == null || !current.isComplex(name)) {
+                throw missing(path);
+            }
+            Object nested = step.getValue();
+            if (nested == null) {
+                return null;
+            }
+            if (!(nested instanceof ViewModel child)) {
+                throw missing(path);
+            }
+            current = child;
+        }
+        String last = names[names.length - 1];
+        Property<?> attribute = current.property(last);
+        if (attribute == null) {
+            throw missing(path);
+        }
+        return new Resolved(attribute, current.isComplex(last));
+    }
+
+    private static IllegalArgumentException missing(String path) {
+        return new IllegalArgumentException("No read-write attribute for path \"" + path + "\"");
+    }
+
+    private static Converter converter(ApplicationContext context, String className) {
+        try {
+            Class<?> type = Class.forName(className);
+            Object instance = context.getComponent(type.asSubclass(Object.class));
+            if (!(instance instanceof Converter created)) {
+                throw new IllegalArgumentException("Not a converter: " + className);
+            }
+            return created;
+        } catch (ClassNotFoundException failure) {
+            throw new IllegalArgumentException("No converter " + className, failure);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignConverted(Property<?> controlProperty, Property<?> attribute, Converter converter,
+                                       ViewModel viewModel, String path, boolean towardView, boolean towardModel) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> source = (Property<Object>) attribute;
+        Link link = new Link();
+        pushControl(control, source, converter, viewModel, path, link);
+        if (towardView) {
+            source.addListener((observable, oldValue, newValue) -> {
+                if (!link.applying) {
+                    pushControl(control, source, converter, viewModel, path, link);
+                }
+            });
+        }
+        if (towardModel) {
+            control.addListener((observable, oldValue, newValue) -> {
+                if (!link.applying) {
+                    pushAttribute(control, source, converter, viewModel, path, link);
+                }
+            });
+        }
+    }
+
+    private static void pushControl(Property<Object> control, Property<Object> attribute, Converter converter,
+                                    ViewModel viewModel, String path, Link link) {
+        try {
+            Object shown = converter.toControlValue(attribute.getValue());
+            link.applying = true;
+            try {
+                control.setValue(shown);
+                link.committedControl = shown;
+            } finally {
+                link.applying = false;
+            }
+            viewModel.clearBindingFailure(path);
+        } catch (RuntimeException failure) {
+            viewModel.reportBindingFailure(path, failureText(failure));
+        }
+    }
+
+    private static void pushAttribute(Property<Object> control, Property<Object> attribute, Converter converter,
+                                      ViewModel viewModel, String path, Link link) {
+        try {
+            Object converted = converter.toAttributeValue(control.getValue());
+            link.applying = true;
+            try {
+                attribute.setValue(converted);
+                link.committedControl = control.getValue();
+            } finally {
+                link.applying = false;
+            }
+            viewModel.clearBindingFailure(path);
+        } catch (RuntimeException failure) {
+            link.applying = true;
+            try {
+                control.setValue(link.committedControl);
+            } finally {
+                link.applying = false;
+            }
+            viewModel.reportBindingFailure(path, failureText(failure));
+        }
+    }
+
+    private static String failureText(RuntimeException failure) {
+        String text = failure.getMessage();
+        if (text == null || text.isEmpty()) {
+            return "Conversion failed";
+        }
+        return text;
+    }
+
+    /**
+     * Guards one converted binding against hearing its own writes, and remembers the last
+     * control value that was successfully shown.
+     */
+    private static final class Link {
+        private boolean applying;
+        private Object committedControl;
+    }
+
+    private static Property<?> controlProperty(Object control, String propertyName) {
+        String methodName = propertyName + "Property";
+        try {
+            Method method = control.getClass().getMethod(methodName);
+            Object value = method.invoke(control);
+            if (!(value instanceof Property<?> property)) {
+                throw new IllegalArgumentException(methodName + " did not return a property");
+            }
+            return property;
+        } catch (NoSuchMethodException failure) {
+            throw new IllegalArgumentException(
+                    "No property " + propertyName + " on " + control.getClass().getName(), failure);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not read property " + propertyName, failure);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignBothComplex(Property<?> controlProperty, Property<?> attribute) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> source = (Property<Object>) attribute;
+        control.setValue(modelBehind(source.getValue()));
+        source.addListener((observable, oldValue, newValue) -> {
+            Object model = modelBehind(newValue);
+            if (control.getValue() != model) {
+                control.setValue(model);
+            }
+        });
+        control.addListener((observable, oldValue, newValue) -> {
+            if (modelBehind(source.getValue()) == newValue) {
+                return;
+            }
+            source.setValue(newValue == null ? null : ViewModels.of(newValue));
+        });
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignTowardViewComplex(Property<?> controlProperty, Property<?> attribute) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> source = (Property<Object>) attribute;
+        control.setValue(modelBehind(source.getValue()));
+        source.addListener((observable, oldValue, newValue) -> control.setValue(modelBehind(newValue)));
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignTowardModelComplex(Property<?> controlProperty, Property<?> attribute) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> source = (Property<Object>) attribute;
+        control.setValue(modelBehind(source.getValue()));
+        control.addListener((observable, oldValue, newValue) -> {
+            if (modelBehind(source.getValue()) == newValue) {
+                return;
+            }
+            source.setValue(newValue == null ? null : ViewModels.of(newValue));
+        });
+    }
+
+    private static Object modelBehind(Object value) {
+        if (value instanceof ViewModel viewModel) {
+            return viewModel.model();
+        }
+        return null;
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void assignList(Property<?> controlProperty, ObservableList<?> values) {
+        ((Property<Object>) controlProperty).setValue(values);
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignBoth(Property<?> controlProperty, Property<?> attribute) {
+        ((Property<Object>) controlProperty).bindBidirectional((Property<Object>) attribute);
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignTowardView(Property<?> controlProperty, Property<?> attribute) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> source = (Property<Object>) attribute;
+        control.setValue(source.getValue());
+        source.addListener((observable, oldValue, newValue) -> control.setValue(newValue));
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void alignTowardModel(Property<?> controlProperty, Property<?> attribute) {
+        Property<Object> control = (Property<Object>) controlProperty;
+        Property<Object> target = (Property<Object>) attribute;
+        control.setValue(target.getValue());
+        control.addListener((observable, oldValue, newValue) -> target.setValue(newValue));
+    }
+}

fx/src/main/java/de/neitzel/fx/view/LoadSession.java

@@ -0,0 +1,60 @@
+package de.neitzel.fx.view;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Holds the binding lists instantiated while one View is loading.
+ * <p>
+ * FXML objects declared in {@code fx:define} are not scene-graph children and have no
+ * {@code fx:id} in the accepted document shape, so each {@link BindingList} registers
+ * itself here from its constructor.
+ */
+final class LoadSession {
+
+    private static final ThreadLocal<LoadSession> CURRENT = new ThreadLocal<>();
+
+    private final List<BindingList> bindingLists = new ArrayList<>();
+
+    private LoadSession() {
+    }
+
+    /**
+     * Starts a session on this thread.
+     *
+     * @return the open session
+     */
+    static LoadSession open() {
+        LoadSession session = new LoadSession();
+        CURRENT.set(session);
+        return session;
+    }
+
+    /**
+     * Drops the session for this thread.
+     */
+    static void close() {
+        CURRENT.remove();
+    }
+
+    /**
+     * Registers a binding list created while a session is open.
+     *
+     * @param bindingList the list FXML just constructed
+     */
+    static void register(BindingList bindingList) {
+        LoadSession session = CURRENT.get();
+        if (session != null) {
+            session.bindingLists.add(bindingList);
+        }
+    }
+
+    /**
+     * Returns the lists registered during this session, in document order.
+     *
+     * @return the binding lists
+     */
+    List<BindingList> bindingLists() {
+        return bindingLists;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/LoadedView.java

@@ -0,0 +1,54 @@
+package de.neitzel.fx.view;
+
+import javafx.beans.property.Property;
+import javafx.scene.Parent;
+
+/**
+ * The scene-graph root and ViewModel produced by loading a View for a Model instance.
+ */
+public final class LoadedView {
+
+    private final Parent root;
+    private final ViewModel viewModel;
+
+    /**
+     * Creates the result of one load.
+     *
+     * @param root      the scene-graph root
+     * @param viewModel the ViewModel built for the Model instance
+     */
+    LoadedView(Parent root, ViewModel viewModel) {
+        this.root = root;
+        this.viewModel = viewModel;
+    }
+
+    /**
+     * Returns the scene-graph root.
+     *
+     * @return the root
+     */
+    public Parent getRoot() {
+        return root;
+    }
+
+    /**
+     * Returns the ViewModel the View is bound to.
+     *
+     * @return the ViewModel
+     */
+    public ViewModel getViewModel() {
+        return viewModel;
+    }
+
+    /**
+     * Returns the JavaFX property for an Attribute name.
+     * <p>
+     * The property's class follows the Attribute's declared type.
+     *
+     * @param name the Attribute name
+     * @return the property, or {@code null} when that name is not a read-write Attribute
+     */
+    public Property<?> property(String name) {
+        return viewModel.property(name);
+    }
+}

fx/src/main/java/de/neitzel/fx/view/Message.java

@@ -0,0 +1,74 @@
+package de.neitzel.fx.view;
+
+/**
+ * A notice on a ViewModel with a severity, a text, and a source.
+ */
+public final class Message {
+
+    /**
+     * How serious a notice is.
+     */
+    public enum Severity {
+        /** Informational notice. Not written to the log. */
+        INFO,
+        /** Warning. Not written to the log. */
+        WARN,
+        /** Error. Written to the log. */
+        ERROR,
+        /** Fatal error. Written to the log. */
+        FATAL
+    }
+
+    private final Severity severity;
+    private String text;
+    private final String source;
+
+    /**
+     * Creates a notice.
+     *
+     * @param severity how serious the notice is
+     * @param text     the notice text
+     * @param source   where the notice came from, such as a binding Path
+     */
+    public Message(Severity severity, String text, String source) {
+        this.severity = severity;
+        this.text = text;
+        this.source = source;
+    }
+
+    /**
+     * Returns how serious the notice is.
+     *
+     * @return the severity
+     */
+    public Severity getSeverity() {
+        return severity;
+    }
+
+    /**
+     * Returns the notice text.
+     *
+     * @return the text
+     */
+    public String getText() {
+        return text;
+    }
+
+    /**
+     * Returns where the notice came from.
+     *
+     * @return the source
+     */
+    public String getSource() {
+        return source;
+    }
+
+    /**
+     * Replaces the text of a binding failure that is already in the list.
+     *
+     * @param text the new text
+     */
+    void setText(String text) {
+        this.text = text;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/ViewLoader.java

@@ -0,0 +1,68 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.injection.ApplicationContext;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+
+import java.io.IOException;
+import java.net.URL;
+
+/**
+ * Loads a View for one Model instance.
+ */
+public final class ViewLoader {
+
+    private ViewLoader() {
+    }
+
+    /**
+     * Loads a View for one Model instance.
+     * <p>
+     * Reuses the ViewModel already built for {@code model}, or builds one, then loads {@code fxml}
+     * and applies binding elements declared in {@code fx:define}. A Computed binding writes a
+     * Controller method result to a control and does not write the Model. Direction {@code both}
+     * keeps the control and the Attribute
+     * aligned, so editing the control writes the Attribute immediately. Direction {@code view}
+     * shows the Attribute and follows later property changes without writing the Attribute back.
+     * Direction {@code model} shows the current value, writes the Attribute when the control
+     * changes, and does not push later property changes to the control. A Path of one name is an
+     * Attribute of this View's ViewModel. Further names step into a nested ViewModel, and the
+     * direction applies to the last name. When a Complex attribute along the Path is null, the
+     * control and the Model keep their current values. A collection of simple values is one shared
+     * list: the Direct binding sets the control property to that
+     * {@link javafx.collections.ObservableList}, so an add or remove is visible on both sides.
+     * A path that is not a read-write Attribute fails the load. The context creates a Controller,
+     * and a Converter when a Direct binding names one. A converter that cannot produce a value
+     * keeps the previous value and records one error Message. It does not fail the load.
+     *
+     * @param fxml    the FXML document
+     * @param model   the Model instance
+     * @param context the application context
+     * @return the loaded View
+     * @throws IllegalArgumentException when a Direct binding names a path that is not a read-write Attribute
+     */
+    public static LoadedView load(URL fxml, Object model, ApplicationContext context) {
+        ViewModel viewModel = ViewModels.of(model);
+        LoadSession session = LoadSession.open();
+        try {
+            FXMLLoader loader = new FXMLLoader(fxml);
+            loader.setControllerFactory(type -> controller(context, type));
+            Object loaded = loader.load();
+            if (!(loaded instanceof Parent root)) {
+                throw new IllegalArgumentException("View root must be a parent");
+            }
+            for (BindingList bindingList : session.bindingLists()) {
+                bindingList.apply(loader.getNamespace(), viewModel, loader.getController(), root, context);
+            }
+            return new LoadedView(root, viewModel);
+        } catch (IOException failure) {
+            throw new IllegalStateException("Could not load view " + fxml, failure);
+        } finally {
+            LoadSession.close();
+        }
+    }
+
+    private static Object controller(ApplicationContext context, Class<?> type) {
+        return context.getComponent(type.asSubclass(Object.class));
+    }
+}

fx/src/main/java/de/neitzel/fx/view/ViewModel.java

@@ -0,0 +1,419 @@
+package de.neitzel.fx.view;
+
+import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.DoubleProperty;
+import javafx.beans.property.FloatProperty;
+import javafx.beans.property.IntegerProperty;
+import javafx.beans.property.LongProperty;
+import javafx.beans.property.Property;
+import javafx.beans.property.SimpleBooleanProperty;
+import javafx.beans.property.SimpleDoubleProperty;
+import javafx.beans.property.SimpleFloatProperty;
+import javafx.beans.property.SimpleIntegerProperty;
+import javafx.beans.property.SimpleLongProperty;
+import javafx.beans.property.SimpleObjectProperty;
+import javafx.beans.property.SimpleStringProperty;
+import javafx.beans.value.ChangeListener;
+import javafx.collections.FXCollections;
+import javafx.collections.ObservableList;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.beans.BeanInfo;
+import java.beans.IntrospectionException;
+import java.beans.Introspector;
+import java.beans.PropertyDescriptor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.lang.reflect.WildcardType;
+import java.time.temporal.TemporalAccessor;
+import java.time.temporal.TemporalAmount;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * The object a View binds to, built at runtime for one Model instance.
+ * <p>
+ * Each read-write Attribute that is not declared on {@link Object} is stored as a JavaFX
+ * property under the Attribute name. The property class follows the Attribute's declared type,
+ * including when the current value is null. String, integer, long, float, double, and boolean
+ * attributes use the matching JavaFX property. Any other declared type is an object property.
+ * A Complex attribute, a read-write Attribute whose declared type itself has a read-write
+ * Attribute, stores the ViewModel for the nested Model instance, or null when the Attribute
+ * is null. Strings, numbers, booleans, enums, {@link Date}, {@link Calendar}, and {@code java.time}
+ * values stay simple even when that type has setters. A collection of Model instances is not a
+ * Complex attribute. A list, set, or collection of simple values is an object property whose
+ * value is an {@link ObservableList} of those values. When that attribute's current value is a
+ * list, the observable list is backed by it and stored on the entity when the setter accepts it,
+ * so both sides hold one list. A cycle, or another Attribute that reaches the same instance,
+ * reuses that ViewModel.
+ * The property is set from the Attribute when the ViewModel is created. A null number or
+ * boolean leaves the primitive property at its default. After that, a change of the property
+ * writes the Attribute. A Complex attribute writes the Model instance behind the ViewModel.
+ * A call to the entity's setter does not update the property.
+ * <p>
+ * Beside those attributes, the ViewModel keeps a list of {@link Message}s and the latest one.
+ * The developer can add a message of any severity. Error and fatal messages are written to the log.
+ * Info and warn are not.
+ */
+public class ViewModel {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ViewModel.class);
+
+    private final Object model;
+    private final Map<String, Property<?>> properties = new HashMap<>();
+    private final Set<String> complexAttributes = new HashSet<>();
+    private final List<Message> messages = new ArrayList<>();
+    private final Map<String, Message> bindingFailures = new HashMap<>();
+    private Message latestMessage;
+
+    /**
+     * Builds a ViewModel for one Model instance.
+     *
+     * @param model the Model instance
+     */
+    ViewModel(Object model) {
+        this.model = model;
+        ViewModels.register(model, this);
+        for (PropertyDescriptor descriptor : descriptors(model.getClass())) {
+            Method getter = descriptor.getReadMethod();
+            Method setter = descriptor.getWriteMethod();
+            if (getter == null || setter == null || descriptor.getPropertyType() == null) {
+                continue;
+            }
+            String name = descriptor.getName();
+            Class<?> type = descriptor.getPropertyType();
+            Object current = read(getter, name);
+            if (isComplex(type)) {
+                Property<?> property = new SimpleObjectProperty<>(
+                        current == null ? null : ViewModels.of(current));
+                watchComplex(property, setter, name);
+                properties.put(name, property);
+                complexAttributes.add(name);
+            } else {
+                if (isSimpleValueCollection(getter)) {
+                    current = shareSimpleList(setter, name, current);
+                }
+                Property<?> property = createProperty(type, current);
+                watch(property, setter, name);
+                properties.put(name, property);
+            }
+        }
+    }
+
+    /**
+     * Returns the JavaFX property for an Attribute name.
+     *
+     * @param name the Attribute name
+     * @return the property, or {@code null} when that name is not a read-write Attribute
+     */
+    public Property<?> property(String name) {
+        return properties.get(name);
+    }
+
+    /**
+     * Returns the Model instance this ViewModel was built for.
+     *
+     * @return the Model instance
+     */
+    Object model() {
+        return model;
+    }
+
+    /**
+     * Reports whether an Attribute is complex.
+     *
+     * @param name the Attribute name
+     * @return {@code true} when that Attribute holds a nested ViewModel
+     */
+    boolean isComplex(String name) {
+        return complexAttributes.contains(name);
+    }
+
+    /**
+     * Calls {@code listener} when any Attribute property changes.
+     *
+     * @param listener the listener
+     */
+    @SuppressWarnings("unchecked")
+    void addAttributeListener(ChangeListener<Object> listener) {
+        for (Property<?> property : properties.values()) {
+            ((Property<Object>) property).addListener(listener);
+        }
+    }
+
+    private static List<PropertyDescriptor> descriptors(Class<?> type) {
+        try {
+            BeanInfo info = Introspector.getBeanInfo(type, Object.class);
+            return List.of(info.getPropertyDescriptors());
+        } catch (IntrospectionException failure) {
+            throw new IllegalStateException("Could not introspect " + type.getName(), failure);
+        }
+    }
+
+    private static boolean isComplex(Class<?> type) {
+        if (simpleValue(type)) {
+            return false;
+        }
+        for (PropertyDescriptor descriptor : descriptors(type)) {
+            if (descriptor.getReadMethod() != null
+                    && descriptor.getWriteMethod() != null
+                    && descriptor.getPropertyType() != null) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static boolean simpleValue(Class<?> type) {
+        if (type.isPrimitive() || type.isEnum() || type.isArray()
+                || type == String.class || type == Boolean.class) {
+            return true;
+        }
+        if (Collection.class.isAssignableFrom(type) || Map.class.isAssignableFrom(type)) {
+            return true;
+        }
+        if (Number.class.isAssignableFrom(type)) {
+            return true;
+        }
+        if (Date.class.isAssignableFrom(type) || Calendar.class.isAssignableFrom(type)) {
+            return true;
+        }
+        Package packaged = type.getPackage();
+        return packaged != null && packaged.getName().startsWith("java.time");
+    }
+
+    private static Property<?> createProperty(Class<?> type, Object value) {
+        if (type == String.class) {
+            return new SimpleStringProperty((String) value);
+        }
+        if (type == Integer.class || type == int.class) {
+            return integerProperty(value);
+        }
+        if (type == Long.class || type == long.class) {
+            return longProperty(value);
+        }
+        if (type == Float.class || type == float.class) {
+            return floatProperty(value);
+        }
+        if (type == Double.class || type == double.class) {
+            return doubleProperty(value);
+        }
+        if (type == Boolean.class || type == boolean.class) {
+            return booleanProperty(value);
+        }
+        return new SimpleObjectProperty<>(value);
+    }
+
+    private static IntegerProperty integerProperty(Object value) {
+        SimpleIntegerProperty property = new SimpleIntegerProperty();
+        if (value != null) {
+            property.setValue((Integer) value);
+        }
+        return property;
+    }
+
+    private static LongProperty longProperty(Object value) {
+        SimpleLongProperty property = new SimpleLongProperty();
+        if (value != null) {
+            property.setValue((Long) value);
+        }
+        return property;
+    }
+
+    private static FloatProperty floatProperty(Object value) {
+        SimpleFloatProperty property = new SimpleFloatProperty();
+        if (value != null) {
+            property.setValue((Float) value);
+        }
+        return property;
+    }
+
+    private static DoubleProperty doubleProperty(Object value) {
+        SimpleDoubleProperty property = new SimpleDoubleProperty();
+        if (value != null) {
+            property.setValue((Double) value);
+        }
+        return property;
+    }
+
+    private static BooleanProperty booleanProperty(Object value) {
+        SimpleBooleanProperty property = new SimpleBooleanProperty();
+        if (value != null) {
+            property.setValue((Boolean) value);
+        }
+        return property;
+    }
+
+    private Object read(Method getter, String name) {
+        try {
+            return getter.invoke(model);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not read attribute " + name, failure);
+        }
+    }
+
+    private void watch(Property<?> property, Method setter, String name) {
+        property.addListener((observable, oldValue, newValue) -> write(setter, name, newValue));
+    }
+
+    private void watchComplex(Property<?> property, Method setter, String name) {
+        property.addListener((observable, oldValue, newValue) -> {
+            Object written = newValue instanceof ViewModel viewModel ? viewModel.model() : newValue;
+            write(setter, name, written);
+        });
+    }
+
+    private void write(Method setter, String name, Object value) {
+        try {
+            setter.invoke(model, value);
+        } catch (IllegalAccessException | InvocationTargetException failure) {
+            throw new IllegalStateException("Could not write attribute " + name, failure);
+        }
+    }
+
+    /**
+     * Returns the notices on this ViewModel, beside the Model attributes.
+     *
+     * @return the messages, oldest first
+     */
+    public List<Message> getMessages() {
+        return Collections.unmodifiableList(messages);
+    }
+
+    /**
+     * Returns the notice most recently added.
+     * <p>
+     * An in-place update of a binding failure does not change which notice is latest.
+     *
+     * @return the latest notice, or {@code null} when there is none
+     */
+    public Message getLatestMessage() {
+        return latestMessage;
+    }
+
+    /**
+     * Adds a notice of any severity.
+     *
+     * @param message the notice
+     */
+    public void addMessage(Message message) {
+        messages.add(message);
+        latestMessage = message;
+        logSevere(message);
+    }
+
+    /**
+     * Records one error for a binding Path. A further failure of that Path replaces the text.
+     *
+     * @param path the binding Path
+     * @param text the error text
+     */
+    void reportBindingFailure(String path, String text) {
+        Message existing = bindingFailures.get(path);
+        if (existing != null) {
+            existing.setText(text);
+            logSevere(existing);
+            return;
+        }
+        Message message = new Message(Message.Severity.ERROR, text, path);
+        bindingFailures.put(path, message);
+        addMessage(message);
+    }
+
+    /**
+     * Drops the error recorded for a binding Path after a later conversion succeeds.
+     *
+     * @param path the binding Path
+     */
+    void clearBindingFailure(String path) {
+        Message existing = bindingFailures.remove(path);
+        if (existing == null) {
+            return;
+        }
+        messages.remove(existing);
+        if (latestMessage == existing) {
+            latestMessage = messages.isEmpty() ? null : messages.get(messages.size() - 1);
+        }
+    }
+
+    /**
+     * Writes an error or fatal notice to the log. Info and warn are left out.
+     *
+     * @param message the notice
+     */
+    private static void logSevere(Message message) {
+        Message.Severity severity = message.getSeverity();
+        if (severity == Message.Severity.ERROR || severity == Message.Severity.FATAL) {
+            LOGGER.error(message.getText());
+        }
+    }
+
+    private static boolean isSimpleValueCollection(Method getter) {
+        if (!Collection.class.isAssignableFrom(getter.getReturnType())) {
+            return false;
+        }
+        Class<?> element = elementType(getter.getGenericReturnType());
+        return element != null && isSimpleValue(element);
+    }
+
+    private static Class<?> elementType(Type type) {
+        if (!(type instanceof ParameterizedType parameterized) || parameterized.getActualTypeArguments().length != 1) {
+            return null;
+        }
+        return classOf(parameterized.getActualTypeArguments()[0]);
+    }
+
+    private static Class<?> classOf(Type type) {
+        if (type instanceof Class<?> raw) {
+            return raw;
+        }
+        if (type instanceof ParameterizedType parameterized && parameterized.getRawType() instanceof Class<?> raw) {
+            return raw;
+        }
+        if (type instanceof WildcardType wildcard && wildcard.getUpperBounds().length == 1) {
+            return classOf(wildcard.getUpperBounds()[0]);
+        }
+        return null;
+    }
+
+    private static boolean isSimpleValue(Class<?> type) {
+        if (type == String.class || type == Boolean.class || type == boolean.class || type.isEnum()) {
+            return true;
+        }
+        if (type.isPrimitive()) {
+            return type != char.class && type != void.class;
+        }
+        if (Number.class.isAssignableFrom(type)) {
+            return true;
+        }
+        if (Date.class.isAssignableFrom(type) || Calendar.class.isAssignableFrom(type)) {
+            return true;
+        }
+        return TemporalAccessor.class.isAssignableFrom(type) || TemporalAmount.class.isAssignableFrom(type);
+    }
+
+    @SuppressWarnings("unchecked")
+    private Object shareSimpleList(Method setter, String name, Object current) {
+        if (!(current instanceof Collection<?> collection)) {
+            return current;
+        }
+        ObservableList<Object> observable = current instanceof List<?> list
+                ? FXCollections.observableList((List<Object>) list)
+                : FXCollections.observableArrayList((Collection<Object>) collection);
+        if (setter.getParameterTypes()[0].isAssignableFrom(observable.getClass())) {
+            write(setter, name, observable);
+        }
+        return observable;
+    }
+}

fx/src/main/java/de/neitzel/fx/view/ViewModels.java

@@ -0,0 +1,41 @@
+package de.neitzel.fx.view;
+
+import java.util.IdentityHashMap;
+import java.util.Map;
+
+/**
+ * The ViewModels already built, one for each Model instance.
+ * <p>
+ * Instances are compared by identity, so two Models that are equal still get two ViewModels.
+ */
+final class ViewModels {
+
+    private static final Map<Object, ViewModel> BY_INSTANCE = new IdentityHashMap<>();
+
+    private ViewModels() {
+    }
+
+    /**
+     * Returns the ViewModel for a Model instance, building it when none exists yet.
+     *
+     * @param model the Model instance
+     * @return the ViewModel for that instance
+     */
+    static ViewModel of(Object model) {
+        ViewModel existing = BY_INSTANCE.get(model);
+        if (existing != null) {
+            return existing;
+        }
+        return new ViewModel(model);
+    }
+
+    /**
+     * Records a ViewModel before its Attributes are walked, so a cycle reuses it.
+     *
+     * @param model     the Model instance
+     * @param viewModel the ViewModel under construction
+     */
+    static void register(Object model, ViewModel viewModel) {
+        BY_INSTANCE.put(model, viewModel);
+    }
+}

fx/src/test/java/de/neitzel/fx/view/ComputeAValueTest.java

@@ -0,0 +1,135 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.fx.view.fixture.Person;
+import de.neitzel.injection.ApplicationContext;
+import javafx.application.Platform;
+import javafx.beans.property.Property;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.net.URL;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class ComputeAValueTest {
+
+    @BeforeAll
+    static void startJavaFx() throws InterruptedException {
+        CountDownLatch started = new CountDownLatch(1);
+        try {
+            Platform.startup(started::countDown);
+        } catch (IllegalStateException alreadyStarted) {
+            started.countDown();
+        }
+        if (!started.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX toolkit did not start");
+        }
+    }
+
+    @Test
+    void computedBindingShowsTheMethodResultAndLeavesTheModelUnchanged() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(36);
+            URL fxml = ComputeAValueTest.class.getResource("working-age.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.computed");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            Label workingAgeLabel = (Label) loaded.getRoot().lookup("#workingAgeLabel");
+            assertEquals("initial-age", workingAgeLabel.getText());
+            assertEquals("Ada", person.getName());
+            assertEquals(36, person.getAge());
+        });
+    }
+
+    @Test
+    void typingInAnotherTextFieldUpdatesTheComputedLabel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ComputeAValueTest.class.getResource("working-age.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.computed");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField nameField = (TextField) loaded.getRoot().lookup("#nameField");
+            Label workingAgeLabel = (Label) loaded.getRoot().lookup("#workingAgeLabel");
+            nameField.setText("Grace");
+            assertEquals("typed-age", workingAgeLabel.getText());
+            assertEquals("Grace", person.getName());
+        });
+    }
+
+    @Test
+    void settingAViewModelPropertyUpdatesTheComputedLabel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ComputeAValueTest.class.getResource("working-age.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.computed");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            Label workingAgeLabel = (Label) loaded.getRoot().lookup("#workingAgeLabel");
+            @SuppressWarnings("unchecked")
+            Property<String> name = (Property<String>) loaded.property("name");
+            name.setValue("Edsger");
+            assertEquals("model-age", workingAgeLabel.getText());
+            assertEquals("Edsger", person.getName());
+        });
+    }
+
+    @Test
+    void changingTheComputedLabelDoesNotRunTheMethodAgain() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ComputeAValueTest.class.getResource("working-age.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.computed");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            Label workingAgeLabel = (Label) loaded.getRoot().lookup("#workingAgeLabel");
+            assertEquals("initial-age", workingAgeLabel.getText());
+            workingAgeLabel.setText("sentinel");
+            assertEquals("sentinel", workingAgeLabel.getText());
+        });
+    }
+
+    private static void onFx(FxAction action) throws Exception {
+        if (Platform.isFxApplicationThread()) {
+            action.run();
+            return;
+        }
+        AtomicReference<Throwable> thrown = new AtomicReference<>();
+        CountDownLatch done = new CountDownLatch(1);
+        Platform.runLater(() -> {
+            try {
+                action.run();
+            } catch (Throwable failure) {
+                thrown.set(failure);
+            } finally {
+                done.countDown();
+            }
+        });
+        if (!done.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX thread did not finish");
+        }
+        Throwable failure = thrown.get();
+        if (failure instanceof Exception exception) {
+            throw exception;
+        }
+        if (failure instanceof Error error) {
+            throw error;
+        }
+        if (failure != null) {
+            throw new AssertionError(failure);
+        }
+    }
+
+    @FunctionalInterface
+    private interface FxAction {
+        void run() throws Exception;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/ConvertAndRecordFailureTest.java

@@ -0,0 +1,292 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.fx.view.fixture.Person;
+import de.neitzel.injection.ApplicationContext;
+import javafx.application.Platform;
+import javafx.beans.property.IntegerProperty;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class ConvertAndRecordFailureTest {
+
+    @BeforeAll
+    static void startJavaFx() throws InterruptedException {
+        CountDownLatch started = new CountDownLatch(1);
+        try {
+            Platform.startup(started::countDown);
+        } catch (IllegalStateException alreadyStarted) {
+            started.countDown();
+        }
+        if (!started.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX toolkit did not start");
+        }
+    }
+
+    @Test
+    void injectedConverterPrefixesTheAgeText() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            assertEquals("years:42", ageField.getText());
+        });
+    }
+
+    @Test
+    void typingAPrefixedAgeUpdatesTheModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ageField.setText("years:11");
+            assertEquals(11, person.getAge());
+        });
+    }
+
+    @Test
+    void towardViewLoadsWhenTheReverseMethodIsAbsent() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-view-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            Label ageLabel = (Label) loaded.getRoot().lookup("#ageLabel");
+            assertEquals("shown 42", ageLabel.getText());
+            ageLabel.setText("shown 99");
+            assertEquals(42, person.getAge());
+        });
+    }
+
+    @Test
+    void towardViewConverterFollowsALaterAge() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-and-view-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            Label ageLabel = (Label) loaded.getRoot().lookup("#ageLabel");
+            assertEquals("shown 42", ageLabel.getText());
+            ageField.setText("years:11");
+            assertEquals(11, person.getAge());
+            assertEquals("shown 11", ageLabel.getText());
+        });
+    }
+
+    @Test
+    void towardModelConvertsTypedTextWithoutFollowingTheAttribute() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-model-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            assertEquals("years:42", ageField.getText());
+            ((IntegerProperty) loaded.property("age")).set(7);
+            assertEquals("years:42", ageField.getText());
+            assertEquals(Integer.valueOf(7), person.getAge());
+            ageField.setText("years:8");
+            assertEquals(Integer.valueOf(8), person.getAge());
+            assertEquals("years:8", ageField.getText());
+        });
+    }
+
+    @Test
+    void badAgeTextKeepsThePreviousIntAndOneErrorMessage() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ageField.setText("nope");
+            assertEquals(Integer.valueOf(42), person.getAge());
+            assertEquals("years:42", ageField.getText());
+            ViewModel viewModel = loaded.getViewModel();
+            assertEquals(1, viewModel.getMessages().size());
+            Message message = viewModel.getMessages().get(0);
+            assertEquals(Message.Severity.ERROR, message.getSeverity());
+            assertEquals("age", message.getSource());
+            assertEquals("not a whole number: nope", message.getText());
+            assertSame(message, viewModel.getLatestMessage());
+        });
+    }
+
+    @Test
+    void anotherBadAgeUpdatesTheSameMessage() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ageField.setText("nope");
+            ViewModel viewModel = loaded.getViewModel();
+            Message first = viewModel.getMessages().get(0);
+            ageField.setText("still-bad");
+            assertEquals(1, viewModel.getMessages().size());
+            assertSame(first, viewModel.getMessages().get(0));
+            assertEquals("not a whole number: still-bad", first.getText());
+            assertEquals(Integer.valueOf(42), person.getAge());
+            assertEquals("years:42", ageField.getText());
+        });
+    }
+
+    @Test
+    void aValidAgeRemovesTheFailureMessage() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ageField.setText("nope");
+            ageField.setText("years:11");
+            assertEquals(Integer.valueOf(11), person.getAge());
+            assertEquals("years:11", ageField.getText());
+            assertEquals(0, loaded.getViewModel().getMessages().size());
+            assertNull(loaded.getViewModel().getLatestMessage());
+        });
+    }
+
+    @Test
+    void developerInfoStaysLatestAndIsNotLogged() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ViewModel viewModel = loaded.getViewModel();
+            ageField.setText("nope");
+            String log = captureErr(() -> viewModel.addMessage(
+                    new Message(Message.Severity.INFO, "developer-info-notice", "form")));
+            assertEquals(2, viewModel.getMessages().size());
+            assertEquals("developer-info-notice", viewModel.getLatestMessage().getText());
+            assertEquals(Message.Severity.INFO, viewModel.getLatestMessage().getSeverity());
+            assertFalse(log.contains("developer-info-notice"));
+            ageField.setText("still-bad");
+            assertEquals(2, viewModel.getMessages().size());
+            assertEquals("not a whole number: still-bad", viewModel.getMessages().get(0).getText());
+            assertEquals("developer-info-notice", viewModel.getLatestMessage().getText());
+        });
+    }
+
+    @Test
+    void errorAndFatalMessagesAreWrittenToTheLog() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAge(42);
+            URL fxml = ConvertAndRecordFailureTest.class.getResource("age-both-converted.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField ageField = (TextField) loaded.getRoot().lookup("#ageField");
+            ViewModel viewModel = loaded.getViewModel();
+            String log = captureErr(() -> {
+                viewModel.addMessage(new Message(Message.Severity.WARN, "developer-warn-notice", "form"));
+                viewModel.addMessage(new Message(Message.Severity.ERROR, "developer-error-notice", "form"));
+                viewModel.addMessage(new Message(Message.Severity.FATAL, "developer-fatal-notice", "form"));
+                ageField.setText("nope");
+                ageField.setText("still-bad");
+            });
+            assertFalse(log.contains("developer-warn-notice"));
+            assertTrue(log.contains("developer-error-notice"));
+            assertTrue(log.contains("developer-fatal-notice"));
+            assertTrue(log.contains("not a whole number: nope"));
+            assertTrue(log.contains("not a whole number: still-bad"));
+            assertEquals("not a whole number: still-bad", viewModel.getLatestMessage().getText());
+            assertEquals(4, viewModel.getMessages().size());
+        });
+    }
+
+    private static void onFx(FxAction action) throws Exception {
+        if (Platform.isFxApplicationThread()) {
+            action.run();
+            return;
+        }
+        AtomicReference<Throwable> thrown = new AtomicReference<>();
+        CountDownLatch done = new CountDownLatch(1);
+        Platform.runLater(() -> {
+            try {
+                action.run();
+            } catch (Throwable failure) {
+                thrown.set(failure);
+            } finally {
+                done.countDown();
+            }
+        });
+        if (!done.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX thread did not finish");
+        }
+        Throwable failure = thrown.get();
+        if (failure instanceof Exception exception) {
+            throw exception;
+        }
+        if (failure instanceof Error error) {
+            throw error;
+        }
+        if (failure != null) {
+            throw new AssertionError(failure);
+        }
+    }
+
+    private static String captureErr(FxAction action) throws Exception {
+        PrintStream previous = System.err;
+        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+        PrintStream captured = new PrintStream(buffer, true, StandardCharsets.UTF_8);
+        System.setErr(captured);
+        try {
+            action.run();
+            captured.flush();
+            return buffer.toString(StandardCharsets.UTF_8);
+        } finally {
+            System.setErr(previous);
+        }
+    }
+
+    @FunctionalInterface
+    private interface FxAction {
+        void run() throws Exception;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/ReachNestedAttributeTest.java

@@ -0,0 +1,337 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.fx.view.fixture.Address;
+import de.neitzel.fx.view.fixture.ObjectHolder;
+import de.neitzel.fx.view.fixture.Person;
+import de.neitzel.fx.view.fixture.Role;
+import de.neitzel.injection.ApplicationContext;
+import javafx.application.Platform;
+import javafx.collections.ObservableList;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.net.URL;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class ReachNestedAttributeTest {
+
+    @BeforeAll
+    static void startJavaFx() throws InterruptedException {
+        CountDownLatch started = new CountDownLatch(1);
+        try {
+            Platform.startup(started::countDown);
+        } catch (IllegalStateException alreadyStarted) {
+            started.countDown();
+        }
+        if (!started.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX toolkit did not start");
+        }
+    }
+
+    @Test
+    void complexAttributeHoldsTheViewModelForTheNestedAddress() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setAddress(new Address("Main"));
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            Object addressValue = loaded.property("address").getValue();
+            assertInstanceOf(ViewModel.class, addressValue);
+            assertEquals("Main", ((ViewModel) addressValue).property("street").getValue());
+        });
+    }
+
+    @Test
+    void bothWaysTextFieldReadsAndWritesTheNestedStreet() throws Exception {
+        onFx(() -> {
+            Address address = new Address("Main");
+            Person person = new Person("Ada");
+            person.setAddress(address);
+            URL fxml = ReachNestedAttributeTest.class.getResource("address-street-both.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField streetField = (TextField) loaded.getRoot().lookup("#streetField");
+            assertEquals("Main", streetField.getText());
+            streetField.setText("Oak");
+            assertEquals("Oak", address.getStreet());
+        });
+    }
+
+    @Test
+    void towardViewLabelFollowsTheNestedStreetAndDoesNotWrite() throws Exception {
+        onFx(() -> {
+            Address address = new Address("Main");
+            Person person = new Person("Ada");
+            person.setAddress(address);
+            URL fxml = ReachNestedAttributeTest.class.getResource("address-street-both-and-view.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField streetField = (TextField) loaded.getRoot().lookup("#streetField");
+            Label streetLabel = (Label) loaded.getRoot().lookup("#streetLabel");
+            assertEquals("Main", streetLabel.getText());
+            streetField.setText("Oak");
+            assertEquals("Oak", streetLabel.getText());
+            assertEquals("Oak", address.getStreet());
+            streetLabel.setText("Side");
+            assertEquals("Oak", address.getStreet());
+        });
+    }
+
+    @Test
+    void bothWaysBindingOnAComplexPathYieldsTheModelInstance() throws Exception {
+        onFx(() -> {
+            Address address = new Address("Main");
+            Person person = new Person("Ada");
+            person.setAddress(address);
+            URL fxml = ReachNestedAttributeTest.class.getResource("address-object.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            ObjectHolder addressHolder = (ObjectHolder) loaded.getRoot().lookup("#addressHolder");
+            assertSame(address, addressHolder.getValue());
+            Address moved = new Address("Oak");
+            addressHolder.setValue(moved);
+            assertSame(moved, person.getAddress());
+        });
+    }
+
+    @Test
+    void fillingAMissingAddressStoresTheViewModelAndWritesTheModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ReachNestedAttributeTest.class.getResource("address-object.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            ObjectHolder addressHolder = (ObjectHolder) loaded.getRoot().lookup("#addressHolder");
+            assertNull(addressHolder.getValue());
+            assertNull(person.getAddress());
+            Address address = new Address("Main");
+            addressHolder.setValue(address);
+            assertSame(address, person.getAddress());
+            Object addressValue = loaded.property("address").getValue();
+            assertInstanceOf(ViewModel.class, addressValue);
+            assertEquals("Main", ((ViewModel) addressValue).property("street").getValue());
+        });
+    }
+
+    @Test
+    void missingAddressLeavesTheControlAndTheModelUnchanged() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ReachNestedAttributeTest.class.getResource("address-street-kept.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField streetField = (TextField) loaded.getRoot().lookup("#streetField");
+            assertEquals("kept", streetField.getText());
+            assertNull(person.getAddress());
+        });
+    }
+
+    @Test
+    void nullComplexAttributeHoldsNull() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertNull(loaded.property("address").getValue());
+        });
+    }
+
+    @Test
+    void attributesThatReachTheSameAddressShareItsViewModel() throws Exception {
+        onFx(() -> {
+            Address shared = new Address("Main");
+            Person person = new Person("Ada");
+            person.setHome(shared);
+            person.setWork(shared);
+            URL fxml = ReachNestedAttributeTest.class.getResource("home-work-street.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertSame(loaded.property("home").getValue(), loaded.property("work").getValue());
+            TextField homeField = (TextField) loaded.getRoot().lookup("#homeField");
+            TextField workField = (TextField) loaded.getRoot().lookup("#workField");
+            homeField.setText("Oak");
+            assertEquals("Oak", workField.getText());
+            assertEquals("Oak", shared.getStreet());
+        });
+    }
+
+    @Test
+    void equalAddressesKeepSeparateViewModels() throws Exception {
+        onFx(() -> {
+            Address home = new Address("Main");
+            Address work = new Address("Main");
+            assertEquals(home, work);
+            Person person = new Person("Ada");
+            person.setHome(home);
+            person.setWork(work);
+            URL fxml = ReachNestedAttributeTest.class.getResource("home-work-street.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertNotSame(loaded.property("home").getValue(), loaded.property("work").getValue());
+            TextField homeField = (TextField) loaded.getRoot().lookup("#homeField");
+            TextField workField = (TextField) loaded.getRoot().lookup("#workField");
+            homeField.setText("Oak");
+            assertEquals("Oak", home.getStreet());
+            assertEquals("Main", work.getStreet());
+            assertEquals("Main", workField.getText());
+        });
+    }
+
+    @Test
+    void aPersonWhoIsTheirOwnFriendReusesTheSameViewModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setFriend(person);
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertSame(loaded.getViewModel(), loaded.property("friend").getValue());
+        });
+    }
+
+    @Test
+    void twoPeopleWhoPointAtEachOtherReuseTheViewModelsAlreadyBuilt() throws Exception {
+        onFx(() -> {
+            Person ada = new Person("Ada");
+            Person grace = new Person("Grace");
+            ada.setFriend(grace);
+            grace.setFriend(ada);
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, ada, context);
+            ViewModel graceModel = (ViewModel) loaded.property("friend").getValue();
+            assertEquals("Grace", graceModel.property("name").getValue());
+            assertSame(loaded.getViewModel(), graceModel.property("friend").getValue());
+        });
+    }
+
+    @Test
+    void enumsBooleansAndDateValuesStaySimpleValues() throws Exception {
+        onFx(() -> {
+            Date updated = new Date(0L);
+            Calendar hired = new GregorianCalendar(2020, Calendar.JANUARY, 2);
+            LocalDate born = LocalDate.of(1815, 12, 10);
+            Person person = new Person("Ada");
+            person.setActive(true);
+            person.setRole(Role.ADMIN);
+            person.setBorn(born);
+            person.setUpdated(updated);
+            person.setHired(hired);
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertEquals(true, loaded.property("active").getValue());
+            assertSame(Role.ADMIN, loaded.property("role").getValue());
+            assertEquals(born, loaded.property("born").getValue());
+            assertSame(updated, loaded.property("updated").getValue());
+            assertSame(hired, loaded.property("hired").getValue());
+        });
+    }
+
+    @Test
+    void aCollectionStaysTheCollectionRatherThanAViewModel() throws Exception {
+        onFx(() -> {
+            List<String> tags = new ArrayList<>();
+            tags.add("friend");
+            Person person = new Person("Ada");
+            person.setTags(tags);
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertInstanceOf(ObservableList.class, loaded.property("tags").getValue());
+            @SuppressWarnings("unchecked")
+            ObservableList<String> shown = (ObservableList<String>) loaded.property("tags").getValue();
+            assertEquals(List.of("friend"), shown);
+            assertSame(person.getTags(), shown);
+            shown.add("kin");
+            assertEquals(List.of("friend", "kin"), tags);
+        });
+    }
+
+    @Test
+    void twoLoadsOfTheSamePersonShareTheViewModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ReachNestedAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView first = ViewLoader.load(fxml, person, context);
+            LoadedView second = ViewLoader.load(fxml, person, context);
+            assertSame(first.getViewModel(), second.getViewModel());
+            TextField firstName = (TextField) first.getRoot().lookup("#nameField");
+            TextField secondName = (TextField) second.getRoot().lookup("#nameField");
+            firstName.setText("Grace");
+            assertEquals("Grace", secondName.getText());
+            assertEquals("Grace", person.getName());
+        });
+    }
+
+    private static void onFx(FxAction action) throws Exception {
+        if (Platform.isFxApplicationThread()) {
+            action.run();
+            return;
+        }
+        AtomicReference<Throwable> thrown = new AtomicReference<>();
+        CountDownLatch done = new CountDownLatch(1);
+        Platform.runLater(() -> {
+            try {
+                action.run();
+            } catch (Throwable failure) {
+                thrown.set(failure);
+            } finally {
+                done.countDown();
+            }
+        });
+        if (!done.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX thread did not finish");
+        }
+        Throwable failure = thrown.get();
+        if (failure instanceof Exception exception) {
+            throw exception;
+        }
+        if (failure instanceof Error error) {
+            throw error;
+        }
+        if (failure != null) {
+            throw new AssertionError(failure);
+        }
+    }
+
+    @FunctionalInterface
+    private interface FxAction {
+        void run() throws Exception;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/ShowAListOfSimpleValuesTest.java

@@ -0,0 +1,99 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.fx.view.fixture.Person;
+import de.neitzel.injection.ApplicationContext;
+import javafx.application.Platform;
+import javafx.scene.control.ListView;
+import javafx.scene.layout.VBox;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class ShowAListOfSimpleValuesTest {
+
+    @BeforeAll
+    static void startJavaFx() throws InterruptedException {
+        CountDownLatch started = new CountDownLatch(1);
+        try {
+            Platform.startup(started::countDown);
+        } catch (IllegalStateException alreadyStarted) {
+            started.countDown();
+        }
+        if (!started.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX toolkit did not start");
+        }
+    }
+
+    @Test
+    void listViewAndPersonShareTheTagList() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            person.setTags(new ArrayList<>(List.of("red", "blue")));
+            URL fxml = ShowAListOfSimpleValuesTest.class.getResource("tags-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            VBox root = (VBox) loaded.getRoot();
+            assertEquals(1, root.getChildren().size());
+            @SuppressWarnings("unchecked")
+            ListView<String> tags = (ListView<String>) root.lookup("#tags");
+            assertEquals(List.of("red", "blue"), List.copyOf(tags.getItems()));
+            assertEquals("red", tags.getItems().get(0));
+            assertEquals("blue", tags.getItems().get(1));
+            assertSame(person.getTags(), tags.getItems());
+            tags.getItems().add("green");
+            assertEquals(List.of("red", "blue", "green"), List.copyOf(person.getTags()));
+            person.getTags().add("gold");
+            assertEquals(List.of("red", "blue", "green", "gold"), List.copyOf(tags.getItems()));
+            tags.getItems().remove("blue");
+            assertEquals(List.of("red", "green", "gold"), List.copyOf(person.getTags()));
+        });
+    }
+
+    private static void onFx(FxAction action) throws Exception {
+        if (Platform.isFxApplicationThread()) {
+            action.run();
+            return;
+        }
+        AtomicReference<Throwable> thrown = new AtomicReference<>();
+        CountDownLatch done = new CountDownLatch(1);
+        Platform.runLater(() -> {
+            try {
+                action.run();
+            } catch (Throwable failure) {
+                thrown.set(failure);
+            } finally {
+                done.countDown();
+            }
+        });
+        if (!done.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX thread did not finish");
+        }
+        Throwable failure = thrown.get();
+        if (failure instanceof Exception exception) {
+            throw exception;
+        }
+        if (failure instanceof Error error) {
+            throw error;
+        }
+        if (failure != null) {
+            throw new AssertionError(failure);
+        }
+    }
+
+    @FunctionalInterface
+    private interface FxAction {
+        void run() throws Exception;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/ShowAndEditOneAttributeTest.java

@@ -0,0 +1,160 @@
+package de.neitzel.fx.view;
+
+import de.neitzel.fx.view.fixture.Person;
+import de.neitzel.injection.ApplicationContext;
+import javafx.application.Platform;
+import javafx.beans.property.IntegerProperty;
+import javafx.scene.control.Label;
+import javafx.scene.control.TextField;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.net.URL;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class ShowAndEditOneAttributeTest {
+
+    @BeforeAll
+    static void startJavaFx() throws InterruptedException {
+        CountDownLatch started = new CountDownLatch(1);
+        try {
+            Platform.startup(started::countDown);
+        } catch (IllegalStateException alreadyStarted) {
+            started.countDown();
+        }
+        if (!started.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX toolkit did not start");
+        }
+    }
+
+    @Test
+    void bothWaysTextFieldShowsTheNameAndTypingUpdatesTheModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField nameField = (TextField) loaded.getRoot().lookup("#nameField");
+            assertEquals("Ada", nameField.getText());
+            nameField.setText("Grace");
+            assertEquals("Grace", person.getName());
+        });
+    }
+
+    @Test
+    void towardViewLabelShowsTheNameFollowsTheFieldAndDoesNotWriteTheModel() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("name-both-and-view.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            TextField nameField = (TextField) loaded.getRoot().lookup("#nameField");
+            Label nameLabel = (Label) loaded.getRoot().lookup("#nameLabel");
+            assertEquals("Ada", nameLabel.getText());
+            nameField.setText("Grace");
+            assertEquals("Grace", nameLabel.getText());
+            assertEquals("Grace", person.getName());
+            nameLabel.setText("Hopper");
+            assertEquals("Grace", person.getName());
+        });
+    }
+
+    @Test
+    void entitySetterAfterLoadLeavesTheTextControlUnchanged() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            person.setName("Grace");
+            TextField nameField = (TextField) loaded.getRoot().lookup("#nameField");
+            assertEquals("Ada", nameField.getText());
+        });
+    }
+
+    @Test
+    void bindingAReadOnlyGetterFailsTheLoad() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("read-only-title.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            IllegalArgumentException failure = assertThrows(IllegalArgumentException.class,
+                    () -> ViewLoader.load(fxml, person, context));
+            assertTrue(failure.getMessage().contains("title"));
+        });
+    }
+
+    @Test
+    void bindingAMethodDeclaredOnObjectFailsTheLoad() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("object-class.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            IllegalArgumentException failure = assertThrows(IllegalArgumentException.class,
+                    () -> ViewLoader.load(fxml, person, context));
+            assertTrue(failure.getMessage().contains("class"));
+        });
+    }
+
+    @Test
+    void nullIntegerAttributeUsesAnIntegerProperty() throws Exception {
+        onFx(() -> {
+            Person person = new Person("Ada");
+            URL fxml = ShowAndEditOneAttributeTest.class.getResource("name-both-ways.fxml");
+            assertNotNull(fxml);
+            ApplicationContext context = new ApplicationContext("de.neitzel.fx.view.fixture");
+            LoadedView loaded = ViewLoader.load(fxml, person, context);
+            assertInstanceOf(IntegerProperty.class, loaded.property("age"));
+        });
+    }
+
+    private static void onFx(FxAction action) throws Exception {
+        if (Platform.isFxApplicationThread()) {
+            action.run();
+            return;
+        }
+        AtomicReference<Throwable> thrown = new AtomicReference<>();
+        CountDownLatch done = new CountDownLatch(1);
+        Platform.runLater(() -> {
+            try {
+                action.run();
+            } catch (Throwable failure) {
+                thrown.set(failure);
+            } finally {
+                done.countDown();
+            }
+        });
+        if (!done.await(10, TimeUnit.SECONDS)) {
+            fail("JavaFX thread did not finish");
+        }
+        Throwable failure = thrown.get();
+        if (failure instanceof Exception exception) {
+            throw exception;
+        }
+        if (failure instanceof Error error) {
+            throw error;
+        }
+        if (failure != null) {
+            throw new AssertionError(failure);
+        }
+    }
+
+    @FunctionalInterface
+    private interface FxAction {
+        void run() throws Exception;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/computed/WorkingAgeController.java

@@ -0,0 +1,30 @@
+package de.neitzel.fx.view.computed;
+
+import jakarta.inject.Singleton;
+import javafx.fxml.FXML;
+import javafx.scene.control.TextField;
+
+/**
+ * Controller that derives a label from the name field and does not write the Model.
+ */
+@Singleton
+public class WorkingAgeController {
+
+    @FXML
+    private TextField nameField;
+
+    /**
+     * Returns a literal chosen from the current name field.
+     *
+     * @return the value written to the label
+     */
+    public String workingAge() {
+        if ("Ada".equals(nameField.getText())) {
+            return "initial-age";
+        }
+        if ("Grace".equals(nameField.getText())) {
+            return "typed-age";
+        }
+        return "model-age";
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/Address.java

@@ -0,0 +1,54 @@
+package de.neitzel.fx.view.fixture;
+
+import java.util.Objects;
+
+/**
+ * Ordinary nested model used by view-loading tests.
+ * <p>
+ * Equality follows the street, so two addresses with the same street are equal while remaining
+ * different instances.
+ */
+public class Address {
+
+    private String street;
+
+    /**
+     * Creates an address with the given street.
+     *
+     * @param street the current street
+     */
+    public Address(String street) {
+        this.street = street;
+    }
+
+    /**
+     * Returns the street.
+     *
+     * @return the street
+     */
+    public String getStreet() {
+        return street;
+    }
+
+    /**
+     * Sets the street.
+     *
+     * @param street the street
+     */
+    public void setStreet(String street) {
+        this.street = street;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other instanceof Address address) {
+            return Objects.equals(street, address.street);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(street);
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/AgeUnit.java

@@ -0,0 +1,19 @@
+package de.neitzel.fx.view.fixture;
+
+import jakarta.inject.Singleton;
+
+/**
+ * Service whose text a converter must show, so a test can see that injection ran.
+ */
+@Singleton
+public class AgeUnit {
+
+    /**
+     * Returns the prefix written in front of an age.
+     *
+     * @return the prefix
+     */
+    public String prefix() {
+        return "years:";
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/ObjectHolder.java

@@ -0,0 +1,40 @@
+package de.neitzel.fx.view.fixture;
+
+import javafx.beans.property.ObjectProperty;
+import javafx.beans.property.SimpleObjectProperty;
+import javafx.scene.layout.Pane;
+
+/**
+ * A small control whose value is an object, used to bind a Complex attribute.
+ */
+public class ObjectHolder extends Pane {
+
+    private final ObjectProperty<Object> value = new SimpleObjectProperty<>(this, "value");
+
+    /**
+     * Returns the value property.
+     *
+     * @return the value property
+     */
+    public ObjectProperty<Object> valueProperty() {
+        return value;
+    }
+
+    /**
+     * Returns the current value.
+     *
+     * @return the value
+     */
+    public Object getValue() {
+        return value.get();
+    }
+
+    /**
+     * Sets the value.
+     *
+     * @param value the value
+     */
+    public void setValue(Object value) {
+        this.value.set(value);
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/Person.java

@@ -0,0 +1,259 @@
+package de.neitzel.fx.view.fixture;
+
+import java.time.LocalDate;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * Ordinary model used by view-loading tests.
+ */
+public class Person {
+
+    private String name;
+    private Integer age;
+    private boolean active;
+    private Address address;
+    private Address home;
+    private Address work;
+    private Person friend;
+    private Role role;
+    private LocalDate born;
+    private Date updated;
+    private Calendar hired;
+    private List<String> tags;
+
+    /**
+     * Creates a person with the given name.
+     *
+     * @param name the current name
+     */
+    public Person(String name) {
+        this.name = name;
+    }
+
+    /**
+     * Returns the name.
+     *
+     * @return the name
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Sets the name.
+     *
+     * @param name the name
+     */
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    /**
+     * Returns a title that cannot be written.
+     *
+     * @return the title
+     */
+    public String getTitle() {
+        return "Doctor";
+    }
+
+    /**
+     * Returns the age. The value may be null.
+     *
+     * @return the age
+     */
+    public Integer getAge() {
+        return age;
+    }
+
+    /**
+     * Sets the age.
+     *
+     * @param age the age
+     */
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+    /**
+     * Returns the address.
+     *
+     * @return the address, or {@code null} when the person has none
+     */
+    public Address getAddress() {
+        return address;
+    }
+
+    /**
+     * Sets the address.
+     *
+     * @param address the address
+     */
+    public void setAddress(Address address) {
+        this.address = address;
+    }
+
+    /**
+     * Returns the home address.
+     *
+     * @return the home address
+     */
+    public Address getHome() {
+        return home;
+    }
+
+    /**
+     * Sets the home address.
+     *
+     * @param home the home address
+     */
+    public void setHome(Address home) {
+        this.home = home;
+    }
+
+    /**
+     * Returns the work address.
+     *
+     * @return the work address
+     */
+    public Address getWork() {
+        return work;
+    }
+
+    /**
+     * Sets the work address.
+     *
+     * @param work the work address
+     */
+    public void setWork(Address work) {
+        this.work = work;
+    }
+
+    /**
+     * Returns the friend.
+     *
+     * @return the friend
+     */
+    public Person getFriend() {
+        return friend;
+    }
+
+    /**
+     * Sets the friend.
+     *
+     * @param friend the friend
+     */
+    public void setFriend(Person friend) {
+        this.friend = friend;
+    }
+
+    /**
+     * Returns whether the person is active.
+     *
+     * @return {@code true} when the person is active
+     */
+    public boolean isActive() {
+        return active;
+    }
+
+    /**
+     * Sets whether the person is active.
+     *
+     * @param active {@code true} when the person is active
+     */
+    public void setActive(boolean active) {
+        this.active = active;
+    }
+
+    /**
+     * Returns the role.
+     *
+     * @return the role
+     */
+    public Role getRole() {
+        return role;
+    }
+
+    /**
+     * Sets the role.
+     *
+     * @param role the role
+     */
+    public void setRole(Role role) {
+        this.role = role;
+    }
+
+    /**
+     * Returns the birth date.
+     *
+     * @return the birth date
+     */
+    public LocalDate getBorn() {
+        return born;
+    }
+
+    /**
+     * Sets the birth date.
+     *
+     * @param born the birth date
+     */
+    public void setBorn(LocalDate born) {
+        this.born = born;
+    }
+
+    /**
+     * Returns the last update.
+     *
+     * @return the last update
+     */
+    public Date getUpdated() {
+        return updated;
+    }
+
+    /**
+     * Sets the last update.
+     *
+     * @param updated the last update
+     */
+    public void setUpdated(Date updated) {
+        this.updated = updated;
+    }
+
+    /**
+     * Returns the hire date.
+     *
+     * @return the hire date
+     */
+    public Calendar getHired() {
+        return hired;
+    }
+
+    /**
+     * Sets the hire date.
+     *
+     * @param hired the hire date
+     */
+    public void setHired(Calendar hired) {
+        this.hired = hired;
+    }
+
+    /**
+     * Returns the tags. The value may be null.
+     *
+     * @return the tags
+     */
+    public List<String> getTags() {
+        return tags;
+    }
+
+    /**
+     * Sets the tags.
+     *
+     * @param tags the tags
+     */
+    public void setTags(List<String> tags) {
+        this.tags = tags;
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/PrefixedAgeConverter.java

@@ -0,0 +1,55 @@
+package de.neitzel.fx.view.fixture;
+
+import de.neitzel.fx.view.Converter;
+import jakarta.inject.Inject;
+import jakarta.inject.Singleton;
+
+/**
+ * Converts an age using the prefix from {@link AgeUnit}.
+ */
+@Singleton
+public class PrefixedAgeConverter implements Converter {
+
+    private final AgeUnit ageUnit;
+
+    /**
+     * Creates a converter that reads its prefix from the injected service.
+     *
+     * @param ageUnit the service that supplies the prefix
+     */
+    @Inject
+    public PrefixedAgeConverter(AgeUnit ageUnit) {
+        this.ageUnit = ageUnit;
+    }
+
+    /**
+     * Writes the injected prefix in front of the age.
+     *
+     * @param attributeValue the age
+     * @return the control text
+     */
+    @Override
+    public Object toControlValue(Object attributeValue) {
+        return ageUnit.prefix() + attributeValue;
+    }
+
+    /**
+     * Reads an age that starts with the injected prefix.
+     *
+     * @param controlValue the control text
+     * @return the age
+     */
+    @Override
+    public Object toAttributeValue(Object controlValue) {
+        String text = controlValue == null ? "" : controlValue.toString();
+        String prefix = ageUnit.prefix();
+        if (!text.startsWith(prefix)) {
+            throw new IllegalArgumentException("not a whole number: " + text);
+        }
+        try {
+            return Integer.valueOf(text.substring(prefix.length()));
+        } catch (NumberFormatException failure) {
+            throw new IllegalArgumentException("not a whole number: " + text);
+        }
+    }
+}

fx/src/test/java/de/neitzel/fx/view/fixture/Role.java

@@ -0,0 +1,9 @@
+package de.neitzel.fx.view.fixture;
+
+/**
+ * A simple enum Attribute used by view-loading tests.
+ */
+public enum Role {
+    MEMBER,
+    ADMIN
+}

fx/src/test/java/de/neitzel/fx/view/fixture/ShownAgeConverter.java

@@ -0,0 +1,22 @@
+package de.neitzel.fx.view.fixture;
+
+import de.neitzel.fx.view.Converter;
+import jakarta.inject.Singleton;
+
+/**
+ * Shows an age and has no reverse conversion.
+ */
+@Singleton
+public class ShownAgeConverter implements Converter {
+
+    /**
+     * Turns the age into label text.
+     *
+     * @param attributeValue the age
+     * @return the label text
+     */
+    @Override
+    public Object toControlValue(Object attributeValue) {
+        return "shown " + attributeValue;
+    }
+}

fx/src/test/resources/de/neitzel/fx/view/address-object.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+<?import de.neitzel.fx.view.fixture.ObjectHolder?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="addressHolder" property="value" path="address" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <ObjectHolder fx:id="addressHolder" id="addressHolder"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/address-street-both-and-view.fxml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="streetField" property="text" path="address.street" direction="both"/>
+            <DirectBinding control="streetLabel" property="text" path="address.street" direction="view"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="streetField" id="streetField"/>
+    <Label fx:id="streetLabel" id="streetLabel"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/address-street-both.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="streetField" property="text" path="address.street" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="streetField" id="streetField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/address-street-kept.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="streetField" property="text" path="address.street" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="streetField" id="streetField" text="kept"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/age-both-and-view-converted.fxml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="ageField" property="text" path="age" direction="both"
+                           converter="de.neitzel.fx.view.fixture.PrefixedAgeConverter"/>
+            <DirectBinding control="ageLabel" property="text" path="age" direction="view"
+                           converter="de.neitzel.fx.view.fixture.ShownAgeConverter"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="ageField" id="ageField"/>
+    <Label fx:id="ageLabel" id="ageLabel"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/age-both-converted.fxml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="ageField" property="text" path="age" direction="both"
+                           converter="de.neitzel.fx.view.fixture.PrefixedAgeConverter"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="ageField" id="ageField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/age-model-converted.fxml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="ageField" property="text" path="age" direction="model"
+                           converter="de.neitzel.fx.view.fixture.PrefixedAgeConverter"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="ageField" id="ageField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/age-view-converted.fxml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="ageLabel" property="text" path="age" direction="view"
+                           converter="de.neitzel.fx.view.fixture.ShownAgeConverter"/>
+        </BindingList>
+    </fx:define>
+    <Label fx:id="ageLabel" id="ageLabel"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/home-work-street.fxml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="homeField" property="text" path="home.street" direction="both"/>
+            <DirectBinding control="workField" property="text" path="work.street" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="homeField" id="homeField"/>
+    <TextField fx:id="workField" id="workField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/name-both-and-view.fxml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="nameField" property="text" path="name" direction="both"/>
+            <DirectBinding control="nameLabel" property="text" path="name" direction="view"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="nameField" id="nameField"/>
+    <Label fx:id="nameLabel" id="nameLabel"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/name-both-ways.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="nameField" property="text" path="name" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="nameField" id="nameField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/object-class.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="classField" property="text" path="class" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="classField" id="classField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/read-only-title.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="titleField" property="text" path="title" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="titleField" id="titleField"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/tags-both-ways.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.ListView?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="tags" property="items" path="tags" direction="both"/>
+        </BindingList>
+    </fx:define>
+    <ListView fx:id="tags" id="tags"/>
+</VBox>

fx/src/test/resources/de/neitzel/fx/view/working-age.fxml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.layout.VBox?>
+<?import de.neitzel.fx.view.BindingList?>
+<?import de.neitzel.fx.view.ComputedBinding?>
+<?import de.neitzel.fx.view.DirectBinding?>
+
+<VBox xmlns="http://javafx.com/javafx" xmlns:fx="http://javafx.com/fxml"
+      fx:controller="de.neitzel.fx.view.computed.WorkingAgeController">
+    <fx:define>
+        <BindingList>
+            <DirectBinding control="nameField" property="text" path="name" direction="both"/>
+            <ComputedBinding control="workingAgeLabel" property="text" method="#workingAge"/>
+        </BindingList>
+    </fx:define>
+    <TextField fx:id="nameField" id="nameField"/>
+    <Label fx:id="workingAgeLabel" id="workingAgeLabel"/>
+</VBox>