Change field annotations to take precedence over registered type adapters.

gson/src/main/java/com/google/gson/Gson.java

@@ -49,10 +49,8 @@ import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 /**
  * This is the main class for using Gson. Gson is typically used by first constructing a
@@ -115,15 +113,6 @@ public final class Gson {
   private final Map<TypeToken<?>, TypeAdapter<?>> typeTokenCache
       = Collections.synchronizedMap(new HashMap<TypeToken<?>, TypeAdapter<?>>());
 
-  /** Indicates whether Gson is in the phase of constructor invocation. It is used to determine
-   * whether to add a constructor in preconfiguredGeneratedTypeAdapter set or not. */
-  private boolean inConstructorPhase = true;
-  /** List of type adapters that are generated by Gson during its constructor */
-  private Set<TypeAdapter<?>> preconfiguredGeneratedTypeAdapters = new HashSet<TypeAdapter<?>>();
-  /** List of type adapters that are generated by Gson during toJson/fromJson. */
-  private final ThreadLocal<Set<TypeAdapter<?>>> runtimeGeneratedTypeAdapters =
-      new ThreadLocal<Set<TypeAdapter<?>>>();
-
   private final List<TypeAdapterFactory> factories;
   private final ConstructorConstructor constructorConstructor;
 
@@ -254,8 +243,6 @@ public final class Gson {
         constructorConstructor, fieldNamingPolicy, excluder));
 
     this.factories = Collections.unmodifiableList(factories);
-    this.preconfiguredGeneratedTypeAdapters = Collections.unmodifiableSet(preconfiguredGeneratedTypeAdapters);
-    inConstructorPhase = false;
   }
 
   private TypeAdapter<Number> doubleAdapter(boolean serializeSpecialFloatingPointValues) {
@@ -917,26 +904,4 @@ public final class Gson {
         .append("}")
         .toString();
   }
-
-  public static final class $$Internal {
-    public static void addGeneratedTypeAdapter(Gson gson, TypeAdapter<?> typeAdapter) {
-      if (gson.inConstructorPhase) {
-        gson.preconfiguredGeneratedTypeAdapters.add(typeAdapter);
-      } else {
-        Set<TypeAdapter<?>> adapters = getRuntimeGeneratedTypeAdapters(gson);
-        adapters.add(typeAdapter);
-      }
-    }
-    public static boolean isGeneratedTypeAdapter(Gson gson, TypeAdapter<?> typeAdapter) {
-      boolean generated = gson.preconfiguredGeneratedTypeAdapters.contains(typeAdapter);
-      if (!generated) generated = getRuntimeGeneratedTypeAdapters(gson).contains(typeAdapter);
-      return generated;
-    }
-    private static Set<TypeAdapter<?>> getRuntimeGeneratedTypeAdapters(Gson gson) {
-      Set<TypeAdapter<?>> adapters = gson.runtimeGeneratedTypeAdapters.get();
-      if (adapters == null) adapters = new HashSet<TypeAdapter<?>>();
-      gson.runtimeGeneratedTypeAdapters.set(adapters);
-      return adapters;
-    }
-  }
 }

gson/src/main/java/com/google/gson/annotations/JsonAdapter.java

@@ -24,9 +24,8 @@ import java.lang.annotation.Target;
 import com.google.gson.TypeAdapter;
 
 /**
- * An annotation that indicates the Gson {@link TypeAdapter} to use with a class or a field.
+ * An annotation that indicates the Gson {@link TypeAdapter} to use with a class
- * Any type adapters registered in {@link com.google.gson.GsonBuilder} supersede the adapter
+ * or field.
- * specified in this annotation.
  *
  * <p>Here is an example of how this annotation is used:</p>
  * <pre>
@@ -61,9 +60,6 @@ import com.google.gson.TypeAdapter;
  * Since User class specified UserJsonAdapter.class in &#64JsonAdapter annotation, it
  * will automatically be invoked to serialize/deserialize User instances. <br>
  *
- * If the UserJsonAdapter needs a constructor other than a no-args constructor, you must register
- * an {@link com.google.gson.InstanceCreator} for it.
- *
  * <p> Here is an example of how to apply this annotation to a field.
  * <pre>
  * private static final class Gadget {
@@ -74,8 +70,11 @@ import com.google.gson.TypeAdapter;
  *   }
  * }
  * </pre>
- * The above annotation will ensure UserJsonAdapter2 takes precedence over UserJsonAdapter
+ *
- * for the user field of the Gadget class.
+ * It's possible to specify different type adapters on a field, that
+ * field's type, and in the {@link com.google.gson.GsonBuilder}. Field
+ * annotations take precedence over {@code GsonBuilder}-registered type
+ * adapters, which in turn take precedence over annotated types.
  *
  * @since 2.3
  *

gson/src/main/java/com/google/gson/internal/bind/JsonAdapterAnnotationTypeAdapterFactory.java

@@ -38,22 +38,11 @@ public final class JsonAdapterAnnotationTypeAdapterFactory implements TypeAdapte
     this.constructorConstructor = constructorConstructor;
   }
 
-  @SuppressWarnings({ "rawtypes", "unchecked" })
+  @SuppressWarnings({"rawtypes", "unchecked"})
   public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> targetType) {
-    Class<? super T> clazz = targetType.getRawType();
+    JsonAdapter annotation = targetType.getRawType().getAnnotation(JsonAdapter.class);
-    JsonAdapter annotation = clazz.getAnnotation(JsonAdapter.class);
+    return annotation != null
-    if (annotation == null) return null;
+        ? (TypeAdapter<T>) constructorConstructor.get(TypeToken.get(annotation.value())).construct()
-    TypeAdapter adapter = getAnnotationTypeAdapter(gson, constructorConstructor, annotation);
+        : null;
-    return adapter;
-  }
-
-  static TypeAdapter<?> getAnnotationTypeAdapter(Gson gson,
-      ConstructorConstructor constructorConstructor, JsonAdapter annotation) {
-    Class<? extends TypeAdapter<?>> adapterClass = annotation.value();
-    ObjectConstructor<? extends TypeAdapter<?>> constructor =
-        constructorConstructor.get(TypeToken.get(adapterClass));
-    TypeAdapter<?> adapter = constructor.construct();
-    Gson.$$Internal.addGeneratedTypeAdapter(gson, adapter);
-    return adapter;
   }
 }

gson/src/main/java/com/google/gson/internal/bind/ReflectiveTypeAdapterFactory.java

@@ -16,12 +16,6 @@
 
 package com.google.gson.internal.bind;
 
-import java.io.IOException;
-import java.lang.reflect.Field;
-import java.lang.reflect.Type;
-import java.util.LinkedHashMap;
-import java.util.Map;
-
 import com.google.gson.FieldNamingStrategy;
 import com.google.gson.Gson;
 import com.google.gson.JsonSyntaxException;
@@ -38,6 +32,11 @@ import com.google.gson.reflect.TypeToken;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonToken;
 import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.lang.reflect.Type;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 /**
  * Type adapter that reflects over the fields and methods of a class.
@@ -71,9 +70,7 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
     }
 
     ObjectConstructor<T> constructor = constructorConstructor.get(type);
-    Adapter<T> adapter = new Adapter<T>(constructor, getBoundFields(gson, type, raw));
+    return new Adapter<T>(constructor, getBoundFields(gson, type, raw));
-    Gson.$$Internal.addGeneratedTypeAdapter(gson, adapter);
-    return adapter;
   }
 
   private ReflectiveTypeAdapterFactory.BoundField createBoundField(
@@ -102,14 +99,10 @@ public final class ReflectiveTypeAdapterFactory implements TypeAdapterFactory {
   }
 
   private TypeAdapter<?> getFieldAdapter(Gson gson, Field field, TypeToken<?> fieldType) {
-    TypeAdapter<?> adapter = gson.getAdapter(fieldType);
+    JsonAdapter annotation = field.getAnnotation(JsonAdapter.class);
-    boolean generatedAdapter = Gson.$$Internal.isGeneratedTypeAdapter(gson, adapter);
+    return (annotation != null)
-    if (generatedAdapter && field.isAnnotationPresent(JsonAdapter.class)) {
+        ? constructorConstructor.get(TypeToken.get(annotation.value())).construct()
-      JsonAdapter annotation = field.getAnnotation(JsonAdapter.class);
+        : gson.getAdapter(fieldType);
-      return JsonAdapterAnnotationTypeAdapterFactory.getAnnotationTypeAdapter(
-          gson, constructorConstructor, annotation);
-    }
-    return adapter;
   }
 
   private Map<String, BoundField> getBoundFields(Gson context, TypeToken<?> type, Class<?> raw) {

gson/src/test/java/com/google/gson/functional/JsonAdapterAnnotationOnFieldsTest.java

@@ -16,56 +16,64 @@
 
 package com.google.gson.functional;
 
-import java.io.IOException;
-
-import junit.framework.TestCase;
-
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.TypeAdapter;
 import com.google.gson.annotations.JsonAdapter;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import junit.framework.TestCase;
 
 /**
  * Functional tests for the {@link com.google.gson.annotations.JsonAdapter} annotation on fields.
  */
 public final class JsonAdapterAnnotationOnFieldsTest extends TestCase {
-
+  public void testClassAnnotationAdapterTakesPrecedenceOverDefault() {
-  public void testJsonAdapterInvoked() {
     Gson gson = new Gson();
     String json = gson.toJson(new Computer(new User("Inderjeet Singh")));
-    assertEquals("{\"user\":{\"firstName\":\"Inderjeet\",\"lastName\":\"Singh\"}}", json);
+    assertEquals("{\"user\":\"UserClassAnnotationAdapter\"}", json);
-    Computer computer = gson.fromJson("{'user':{'firstName':'Jesse','lastName':'Wilson'}}", Computer.class);
+    Computer computer = gson.fromJson("{'user':'Inderjeet Singh'}", Computer.class);
-    assertEquals("Jesse Wilson", computer.user.name);
+    assertEquals("UserClassAnnotationAdapter", computer.user.name);
   }
 
-  public void testRegisteredTypeAdapterOverridesFieldAnnotation() {
+  public void testRegisteredTypeAdapterTakesPrecedenceOverClassAnnotationAdapter() {
+    Gson gson = new GsonBuilder()
+        .registerTypeAdapter(User.class, new RegisteredUserAdapter())
+        .create();
+    String json = gson.toJson(new Computer(new User("Inderjeet Singh")));
+    assertEquals("{\"user\":\"RegisteredUserAdapter\"}", json);
+    Computer computer = gson.fromJson("{'user':'Inderjeet Singh'}", Computer.class);
+    assertEquals("RegisteredUserAdapter", computer.user.name);
+  }
+
+  public void testFieldAnnotationTakesPrecedenceOverRegisteredTypeAdapter() {
     Gson gson = new GsonBuilder()
       .registerTypeAdapter(Part.class, new TypeAdapter<Part>() {
         @Override public void write(JsonWriter out, Part part) throws IOException {
-          out.value("registeredAdapter");
+          throw new AssertionError();
         }
+
         @Override public Part read(JsonReader in) throws IOException {
-          return new Part(in.nextString());
+          throw new AssertionError();
         }
       }).create();
     String json = gson.toJson(new Gadget(new Part("screen")));
-    assertEquals("{\"part\":\"registeredAdapter\"}", json);
+    assertEquals("{\"part\":\"PartJsonFieldAnnotationAdapter\"}", json);
-    Gadget gadget = gson.fromJson("{'part':'registeredAdapterValue'}", Gadget.class);
+    Gadget gadget = gson.fromJson("{'part':'screen'}", Gadget.class);
-    assertEquals("registeredAdapterValue", gadget.part.name);
+    assertEquals("PartJsonFieldAnnotationAdapter", gadget.part.name);
   }
 
-  public void testFieldAnnotationSupersedesClassAnnotation() {
+  public void testFieldAnnotationTakesPrecedenceOverClassAnnotation() {
     Gson gson = new Gson();
     String json = gson.toJson(new Computer2(new User("Inderjeet Singh")));
-    assertEquals("{\"user\":\"userJsonAdapter2\"}", json);
+    assertEquals("{\"user\":\"UserFieldAnnotationAdapter\"}", json);
-    Computer2 target = gson.fromJson("{'user':'userJsonAdapter2Value'}", Computer2.class);
+    Computer2 target = gson.fromJson("{'user':'Interjeet Singh'}", Computer2.class);
-    assertEquals("userJsonAdapter2Value", target.user.name);
+    assertEquals("UserFieldAnnotationAdapter", target.user.name);
   }
 
   private static final class Gadget {
-    @JsonAdapter(PartJsonAdapter.class)
+    @JsonAdapter(PartJsonFieldAnnotationAdapter.class)
     final Part part;
     Gadget(Part part) {
       this.part = part;
@@ -79,13 +87,13 @@ public final class JsonAdapterAnnotationOnFieldsTest extends TestCase {
     }
   }
 
-  private static class PartJsonAdapter extends TypeAdapter<Part> {
+  private static class PartJsonFieldAnnotationAdapter extends TypeAdapter<Part> {
     @Override public void write(JsonWriter out, Part part) throws IOException {
-      out.value(part.name);
+      out.value("PartJsonFieldAnnotationAdapter");
     }
     @Override public Part read(JsonReader in) throws IOException {
       in.nextString();
-      return new Part("partJsonAdapter");
+      return new Part("PartJsonFieldAnnotationAdapter");
     }
   }
 
@@ -96,7 +104,7 @@ public final class JsonAdapterAnnotationOnFieldsTest extends TestCase {
     }
   }
 
-  @JsonAdapter(UserJsonAdapter.class)
+  @JsonAdapter(UserClassAnnotationAdapter.class)
   private static class User {
     public final String name;
     private User(String name) {
@@ -104,43 +112,42 @@ public final class JsonAdapterAnnotationOnFieldsTest extends TestCase {
     }
   }
 
-  private static class UserJsonAdapter extends TypeAdapter<User> {
+  private static class UserClassAnnotationAdapter extends TypeAdapter<User> {
     @Override public void write(JsonWriter out, User user) throws IOException {
-      // implement write: combine firstName and lastName into name
+      out.value("UserClassAnnotationAdapter");
-      out.beginObject();
-      String[] parts = user.name.split(" ");
-      out.name("firstName");
-      out.value(parts[0]);
-      out.name("lastName");
-      out.value(parts[1]);
-      out.endObject();
     }
     @Override public User read(JsonReader in) throws IOException {
-      // implement read: split name into firstName and lastName
+      in.nextString();
-      in.beginObject();
+      return new User("UserClassAnnotationAdapter");
-      in.nextName();
-      String firstName = in.nextString();
-      in.nextName();
-      String lastName = in.nextString();
-      in.endObject();
-      return new User(firstName + " " + lastName);
     }
   }
 
   private static final class Computer2 {
     // overrides the JsonAdapter annotation of User with this
-    @JsonAdapter(UserJsonAdapter2.class)
+    @JsonAdapter(UserFieldAnnotationAdapter.class)
     final User user;
     Computer2(User user) {
       this.user = user;
     }
   }
-  private static final class UserJsonAdapter2 extends TypeAdapter<User> {
+
+  private static final class UserFieldAnnotationAdapter extends TypeAdapter<User> {
     @Override public void write(JsonWriter out, User user) throws IOException {
-      out.value("userJsonAdapter2");
+      out.value("UserFieldAnnotationAdapter");
     }
     @Override public User read(JsonReader in) throws IOException {
-      return new User(in.nextString());
+      in.nextString();
+      return new User("UserFieldAnnotationAdapter");
+    }
+  }
+
+  private static final class RegisteredUserAdapter extends TypeAdapter<User> {
+    @Override public void write(JsonWriter out, User user) throws IOException {
+      out.value("RegisteredUserAdapter");
+    }
+    @Override public User read(JsonReader in) throws IOException {
+      in.nextString();
+      return new User("RegisteredUserAdapter");
     }
   }
 
@@ -148,12 +155,12 @@ public final class JsonAdapterAnnotationOnFieldsTest extends TestCase {
     Gson gson = new Gson();
     String json = "{'part1':'name','part2':{'name':'name2'}}";
     GadgetWithTwoParts gadget = gson.fromJson(json, GadgetWithTwoParts.class);
-    assertEquals("partJsonAdapter", gadget.part1.name);
+    assertEquals("PartJsonFieldAnnotationAdapter", gadget.part1.name);
     assertEquals("name2", gadget.part2.name);
   }
 
   private static final class GadgetWithTwoParts {
-    @JsonAdapter(PartJsonAdapter.class) final Part part1;
+    @JsonAdapter(PartJsonFieldAnnotationAdapter.class) final Part part1;
     final Part part2; // Doesn't have the JsonAdapter annotation
     @SuppressWarnings("unused") GadgetWithTwoParts(Part part1, Part part2) {
       this.part1 = part1;