Added Type Adapter for Instant in new Module gson.

2025-04-04 08:32:05 +02:00
parent 9f2463b94c
commit f37d943cba
3 changed files with 102 additions and 0 deletions
@@ -0,0 +1,52 @@
+package de.neitzel.gson.adapter;
+
+import com.google.gson.*;
+
+import java.lang.reflect.Type;
+import java.time.Instant;
+import java.time.format.DateTimeParseException;
+
+/**
+ * A custom Gson type adapter for serializing and deserializing {@link Instant} objects. This adapter handles conversion between
+ * {@code Instant} and its ISO-8601 formatted string representation.
+ * <p>
+ * Implementation details: - Serialization: Converts {@link Instant} to its ISO-8601 string representation. - Deserialization: Parses a
+ * valid ISO-8601 string to an {@link Instant} instance.
+ * <p>
+ * The adapter ensures compliance with the ISO-8601 standard for interoperability. A {@link JsonParseException} is thrown if the provided
+ * JSON element during deserialization does not conform to the supported {@code Instant} format.
+ */
+public class InstantTypeAdapter implements JsonSerializer<Instant>, JsonDeserializer<Instant> {
+
+  /**
+   * Serializes an {@link Instant} object into its ISO-8601 string representation as a {@link JsonElement}.
+   *
+   * @param src       the {@link Instant} object to be serialized
+   * @param typeOfSrc the specific genericized type of {@code src} (typically ignored in this implementation)
+   * @param context   the context of the serialization process to provide custom serialization logic
+   * @return a {@link JsonPrimitive} containing the ISO-8601 formatted string representation of the {@link Instant}
+   */
+  @Override
+  public JsonElement serialize(Instant src, Type typeOfSrc, JsonSerializationContext context) {
+    return new JsonPrimitive(src.toString()); // ISO-8601: "2025-04-02T10:15:30Z"
+  }
+
+  /**
+   * Deserializes a JSON element into an {@link Instant} object.
+   *
+   * @param json    the JSON data being deserialized
+   * @param typeOfT the specific genericized type of the object to deserialize
+   * @param context the deserialization context
+   * @return the deserialized {@link Instant} object
+   * @throws JsonParseException if the JSON element does not represent a valid ISO-8601 instant format
+   */
+  @Override
+  public Instant deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+      throws JsonParseException {
+    try {
+      return Instant.parse(json.getAsString());
+    } catch (DateTimeParseException e) {
+      throw new JsonParseException("Invalid Instant format", e);
+    }
+  }
+}