Add reviewed FXML View generation in both hosts

designer-intellij/src/main/java/de/neitzel/fxdesigner/intellij/IntellijDocuments.java

@@ -104,6 +104,15 @@ public final class IntellijDocuments implements HostServices.Documents, AutoClos
     return future;
   }
 
+  public CompletionStage<DocumentSession> create(URI uri, String text) {
+    return edt(() -> {
+          Files.writeString(
+              Path.of(uri), text, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
+          return uri;
+        })
+        .thenCompose(this::open);
+  }
+
   public CompletionStage<DocumentSession> open(URI uri) {
     return edt(
         () -> {

designer-intellij/src/test/java/de/neitzel/fxdesigner/intellij/IntellijDocumentsTest.java

@@ -6,6 +6,31 @@ import java.nio.file.*;
 import java.util.*;
 
 public final class IntellijDocumentsTest extends BasePlatformTestCase {
+  public void testCreateNeverOverwritesAndSupportsNativeHistory() throws Exception {
+    Path folder = Files.createTempDirectory("designer-create-");
+    com.intellij.openapi.vfs.newvfs.impl.VfsRootAccess.allowRootAccess(
+        getTestRootDisposable(), folder.toRealPath().toString(), folder.toString());
+    var uri = folder.resolve("New.fxml").toUri();
+    try (var docs = new IntellijDocuments(getProject());
+        var d = docs.create(uri, "before").toCompletableFuture().get()) {
+      try {
+        docs.create(uri, "overwrite").toCompletableFuture().get();
+        fail("Existing file overwritten");
+      } catch (java.util.concurrent.ExecutionException expected) {
+        assertInstanceOf(expected.getCause(), FileAlreadyExistsException.class);
+      }
+      d.apply(new EditBatch(0, "edit", List.of(new EditBatch.Replacement(0, 6, "after"))))
+          .toCompletableFuture()
+          .get();
+      assertEquals("before", d.undo().toCompletableFuture().get().text());
+      assertEquals("after", d.redo().toCompletableFuture().get().text());
+      assertEquals("before", Files.readString(Path.of(uri)));
+    } finally {
+      Files.deleteIfExists(Path.of(uri));
+      Files.deleteIfExists(folder);
+    }
+  }
+
   /** Keeps real VFS writes queued until its per-file flush executes them. */
   public void testSaveWaitsForQueuedVfsWrites() throws Exception {
     var fs = com.intellij.openapi.vfs.LocalFileSystem.getInstance();