Added serializeDefault and deserializeDefault methods in contexts that only invoke system type adapters on the top-level object.

With this, the RuntimeTypeAdapterTest passes.

extras/src/main/java/com/google/gson/typeadapters/RuntimeTypeAdapter.java

@@ -184,7 +184,7 @@ public final class RuntimeTypeAdapter<T> implements JsonSerializer<T>, JsonDeser
       throw new JsonParseException("cannot serialize " + srcType.getName()
           + "; did you forget to register a subtype?");
     }
-    JsonElement serialized = context.serialize(src, srcType);
+    JsonElement serialized = context.serializeDefault(src, srcType);
     final JsonObject jsonObject = serialized.getAsJsonObject();
     if (jsonObject.has(typeFieldName)) {
       throw new JsonParseException("cannot serialize " + srcType.getName()
@@ -212,7 +212,7 @@ public final class RuntimeTypeAdapter<T> implements JsonSerializer<T>, JsonDeser
           + label + "; did you forget to register a subtype?");
     }
     @SuppressWarnings("unchecked") // registration requires that subtype extends T
-    T result = (T) context.deserialize(json, subtype);
+    T result = (T) context.deserializeDefault(json, subtype);
     return result;
   }
 }

extras/src/test/java/com/google/gson/typeadapters/RuntimeTypeAdapterTest.java

@@ -50,7 +50,7 @@ public final class RuntimeTypeAdapterTest extends TestCase {
     assertEquals("{\"type\":\"BillingInstrument\",\"ownerName\":\"Jesse\"}",
         gson.toJson(original, BillingInstrument.class));
     BillingInstrument deserialized = gson.fromJson(
-        "{type:'CreditCard',ownerName:'Jesse'}", BillingInstrument.class);
+        "{type:'BillingInstrument',ownerName:'Jesse'}", BillingInstrument.class);
     assertEquals("Jesse", deserialized.ownerName);
   }
 

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

@@ -30,7 +30,7 @@ abstract class BaseMapTypeAdapter
 
   protected static final JsonElement serialize(JsonSerializationContext context,
       Object src, Type srcType) {
-    return context.serialize(src, srcType, false);
+    return context.serialize(src, srcType, false, false);
   }
 
   protected static final Map<Object, Object> constructMapType(

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

@@ -677,7 +677,7 @@ final class DefaultTypeAdapters {
         } else {
           Type childType = (childGenericType == null || childGenericType == Object.class)
               ? child.getClass() : childGenericType;
-          JsonElement element = context.serialize(child, childType, false);
+          JsonElement element = context.serialize(child, childType, false, false);
           array.add(element);
         }
       }

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

@@ -55,29 +55,29 @@ public final class JsonDeserializationContext {
 
 
   private <T> T fromJsonArray(Type arrayType, JsonArray jsonArray,
-      JsonDeserializationContext context) throws JsonParseException {
+      JsonDeserializationContext context, boolean systemOnly) throws JsonParseException {
     JsonArrayDeserializationVisitor<T> visitor = new JsonArrayDeserializationVisitor<T>(
         jsonArray, arrayType, objectNavigator, fieldNamingPolicy,
         objectConstructor, deserializers, context);
-    objectNavigator.accept(new ObjectTypePair(null, arrayType, true), visitor);
+    objectNavigator.accept(new ObjectTypePair(null, arrayType, true, systemOnly), visitor);
     return visitor.getTarget();
   }
 
   private <T> T fromJsonObject(Type typeOfT, JsonObject jsonObject,
-      JsonDeserializationContext context) throws JsonParseException {
+      JsonDeserializationContext context, boolean systemOnly) throws JsonParseException {
     JsonObjectDeserializationVisitor<T> visitor = new JsonObjectDeserializationVisitor<T>(
         jsonObject, typeOfT, objectNavigator, fieldNamingPolicy,
         objectConstructor, deserializers, context);
-    objectNavigator.accept(new ObjectTypePair(null, typeOfT, true), visitor);
+    objectNavigator.accept(new ObjectTypePair(null, typeOfT, true, systemOnly), visitor);
     return visitor.getTarget();
   }
 
   @SuppressWarnings("unchecked")
   private <T> T fromJsonPrimitive(Type typeOfT, JsonPrimitive json,
-      JsonDeserializationContext context) throws JsonParseException {
+      JsonDeserializationContext context, boolean systemOnly) throws JsonParseException {
     JsonObjectDeserializationVisitor<T> visitor = new JsonObjectDeserializationVisitor<T>(
         json, typeOfT, objectNavigator, fieldNamingPolicy, objectConstructor, deserializers, context);
-    objectNavigator.accept(new ObjectTypePair(json.getAsObject(), typeOfT, true), visitor);
+    objectNavigator.accept(new ObjectTypePair(json.getAsObject(), typeOfT, true, systemOnly), visitor);
     Object target = visitor.getTarget();
     return (T) target;
   }
@@ -99,13 +99,31 @@ public final class JsonDeserializationContext {
     if (json == null || json.isJsonNull()) {
       return null;
     } else if (json.isJsonArray()) {
-      Object array = fromJsonArray(typeOfT, json.getAsJsonArray(), this);
+      Object array = fromJsonArray(typeOfT, json.getAsJsonArray(), this, false);
       return (T) array;
     } else if (json.isJsonObject()) {
-      Object object = fromJsonObject(typeOfT, json.getAsJsonObject(), this);
+      Object object = fromJsonObject(typeOfT, json.getAsJsonObject(), this, false);
       return (T) object;
     } else if (json.isJsonPrimitive()) {
-      Object primitive = fromJsonPrimitive(typeOfT, json.getAsJsonPrimitive(), this);
+      Object primitive = fromJsonPrimitive(typeOfT, json.getAsJsonPrimitive(), this, false);
+      return (T) primitive;
+    } else {
+      throw new JsonParseException("Failed parsing JSON source: " + json + " to Json");
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  public <T> T deserializeDefault(JsonElement json, Type typeOfT) throws JsonParseException {
+    if (json == null || json.isJsonNull()) {
+      return null;
+    } else if (json.isJsonArray()) {
+      Object array = fromJsonArray(typeOfT, json.getAsJsonArray(), this, true);
+      return (T) array;
+    } else if (json.isJsonObject()) {
+      Object object = fromJsonObject(typeOfT, json.getAsJsonObject(), this, true);
+      return (T) object;
+    } else if (json.isJsonPrimitive()) {
+      Object primitive = fromJsonPrimitive(typeOfT, json.getAsJsonPrimitive(), this, true);
       return (T) primitive;
     } else {
       throw new JsonParseException("Failed parsing JSON source: " + json + " to Json");

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

@@ -107,7 +107,7 @@ abstract class JsonDeserializationVisitor<T> implements ObjectNavigator.Visitor
   }
 
   private Object visitChild(Type type, JsonDeserializationVisitor<?> childVisitor) {
-    objectNavigator.accept(new ObjectTypePair(null, type, false), childVisitor);
+    objectNavigator.accept(new ObjectTypePair(null, type, false, false), childVisitor);
     // the underlying object may have changed during the construction phase
     // This happens primarily because of custom deserializers
     return childVisitor.getTarget();

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

@@ -109,7 +109,7 @@ final class JsonObjectDeserializationVisitor<T> extends JsonDeserializationVisit
         }
         return true;
       }
-      ObjectTypePair objTypePair = new ObjectTypePair(null, declaredTypeOfField, false);
+      ObjectTypePair objTypePair = new ObjectTypePair(null, declaredTypeOfField, false, false);
       Pair<JsonDeserializer<?>, ObjectTypePair> pair = objTypePair.getMatchingHandler(deserializers);
       if (pair == null) {
         return false;

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

@@ -53,7 +53,7 @@ public final class JsonSerializationContext {
     if (src == null) {
       return JsonNull.INSTANCE;
     }
-    return serialize(src, src.getClass(), false);
+    return serialize(src, src.getClass(), false, false);
   }
 
   /**
@@ -67,16 +67,20 @@ public final class JsonSerializationContext {
    * @return a tree of {@link JsonElement}s corresponding to the serialized form of {@code src}.
    */
   public JsonElement serialize(Object src, Type typeOfSrc) {
-    return serialize(src, typeOfSrc, true);
+    return serialize(src, typeOfSrc, true, false);
   }
 
-  JsonElement serialize(Object src, Type typeOfSrc, boolean preserveType) {
+  public JsonElement serializeDefault(Object src, Type typeOfSrc) {
+    return serialize(src, typeOfSrc, true, true);
+  }
+
+  JsonElement serialize(Object src, Type typeOfSrc, boolean preserveType, boolean defaultOnly) {
     if (src == null) {
       return JsonNull.INSTANCE;
     }
     JsonSerializationVisitor visitor = new JsonSerializationVisitor(
         objectNavigator, fieldNamingPolicy, serializeNulls, serializers, this, ancestors);
-    ObjectTypePair objTypePair = new ObjectTypePair(src, typeOfSrc, preserveType);
+    ObjectTypePair objTypePair = new ObjectTypePair(src, typeOfSrc, preserveType, defaultOnly);
     objectNavigator.accept(objTypePair, visitor);
     return visitor.getJsonElement();
   }

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

@@ -54,7 +54,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   }
 
   public void start(ObjectTypePair node) {
-    if (node == null) {
+    if (node == null || node.isSystemOnly()) {
       return;
     }
     if (ancestors.contains(node)) {
@@ -64,7 +64,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   }
 
   public void end(ObjectTypePair node) {
-    if (node != null) {
+    if (node != null && !node.isSystemOnly()) {
       ancestors.pop();
     }
   }
@@ -81,7 +81,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
       Object child = Array.get(array, i);
       // we should not get more specific component type yet since it is possible
       // that a custom serializer is registered for the componentType
-      addAsArrayElement(new ObjectTypePair(child, componentType, false));
+      addAsArrayElement(new ObjectTypePair(child, componentType, false, false));
     }
   }
 
@@ -93,7 +93,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         }
       } else {
         Object array = getFieldValue(f, obj);
-        addAsChildOfObject(f, new ObjectTypePair(array, typeOfF, false));
+        addAsChildOfObject(f, new ObjectTypePair(array, typeOfF, false, false));
       }
     } catch (CircularReferenceException e) {
       throw e.createDetailedException(f);
@@ -111,7 +111,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         // we should not get more specific component type yet since it is
         // possible that a custom
         // serializer is registered for the componentType
-        addAsChildOfObject(f, new ObjectTypePair(fieldValue, typeOfF, false));
+        addAsChildOfObject(f, new ObjectTypePair(fieldValue, typeOfF, false, false));
       }
     } catch (CircularReferenceException e) {
       throw e.createDetailedException(f);
@@ -200,7 +200,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
         }
         return true;
       }
-      ObjectTypePair objTypePair = new ObjectTypePair(obj, declaredTypeOfField, false);
+      ObjectTypePair objTypePair = new ObjectTypePair(obj, declaredTypeOfField, false, false);
       JsonElement child = findAndInvokeCustomSerializer(objTypePair);
       if (child != null) {
         addChildAsElement(f, child);

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

@@ -45,7 +45,7 @@ final class MappedObjectConstructor implements ObjectConstructor {
 
   @SuppressWarnings("unchecked")
   public <T> T construct(Type typeOfT) {
-    InstanceCreator<T> creator = (InstanceCreator<T>) instanceCreatorMap.getHandlerFor(typeOfT);
+    InstanceCreator<T> creator = (InstanceCreator<T>) instanceCreatorMap.getHandlerFor(typeOfT, false);
     if (creator != null) {
       return creator.createInstance(typeOfT);
     }

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

@@ -27,11 +27,13 @@ final class ObjectTypePair {
   private Object obj;
   final Type type;
   private final boolean preserveType;
+  private final boolean systemOnly;
 
-  ObjectTypePair(Object obj, Type type, boolean preserveType) {
+  ObjectTypePair(Object obj, Type type, boolean preserveType, boolean systemOnly) {
     this.obj = obj;
     this.type = type;
     this.preserveType = preserveType;
+    this.systemOnly = systemOnly;
   }
 
   Object getObject() {
@@ -57,13 +59,13 @@ final class ObjectTypePair {
     if (!preserveType && obj != null) {
       // First try looking up the handler for the actual type
       ObjectTypePair moreSpecificType = toMoreSpecificType();
-      handler = handlers.getHandlerFor(moreSpecificType.type);
+      handler = handlers.getHandlerFor(moreSpecificType.type, systemOnly);
       if (handler != null) {
         return new Pair<HANDLER, ObjectTypePair>(handler, moreSpecificType);
       }
     }
     // Try the specified type
-    handler = handlers.getHandlerFor(type);
+    handler = handlers.getHandlerFor(type, systemOnly);
     return handler == null ? null : new Pair<HANDLER, ObjectTypePair>(handler, this);
   }
 
@@ -75,7 +77,7 @@ final class ObjectTypePair {
     if (actualType == type) {
       return this;
     }
-    return new ObjectTypePair(obj, actualType, true);
+    return new ObjectTypePair(obj, actualType, true, systemOnly);
   }
 
   Type getMoreSpecificType() {
@@ -135,10 +137,14 @@ final class ObjectTypePair {
     } else if (!type.equals(other.type)) {
       return false;
     }
-    return preserveType == other.preserveType;
+    return preserveType == other.preserveType && systemOnly == other.systemOnly;
   }
 
   public boolean isPreserveType() {
     return preserveType;
   }
+
+  public boolean isSystemOnly() {
+    return systemOnly;
+  }
 }

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

@@ -164,10 +164,13 @@ final class ParameterizedTypeHandlerMap<T> {
     modifiable = false;
   }
 
-  public synchronized T getHandlerFor(Type type) {
+  public synchronized T getHandlerFor(Type type, boolean systemOnly) {
-    T handler = userMap.get(type);
+    T handler;
-    if (handler != null) {
+    if (!systemOnly) {
-      return handler;
+      handler = userMap.get(type);
+      if (handler != null) {
+        return handler;
+      }
     }
     handler = systemMap.get(type);
     if (handler != null) {
@@ -175,20 +178,22 @@ final class ParameterizedTypeHandlerMap<T> {
     }
     Class<?> rawClass = $Gson$Types.getRawType(type);
     if (rawClass != type) {
-      handler = getHandlerFor(rawClass);
+      handler = getHandlerFor(rawClass, systemOnly);
       if (handler != null) {
         return handler;
       }
     }
     // check if something registered for type hierarchy
-    handler = getHandlerForTypeHierarchy(rawClass);
+    handler = getHandlerForTypeHierarchy(rawClass, systemOnly);
     return handler;
   }
 
-  private T getHandlerForTypeHierarchy(Class<?> type) {
+  private T getHandlerForTypeHierarchy(Class<?> type, boolean systemOnly) {
-    for (Pair<Class<?>, T> entry : userTypeHierarchyList) {
+    if (!systemOnly) {
-      if (entry.first.isAssignableFrom(type)) {
+      for (Pair<Class<?>, T> entry : userTypeHierarchyList) {
-        return entry.second;
+        if (entry.first.isAssignableFrom(type)) {
+          return entry.second;
+        }
       }
     }
     for (Pair<Class<?>, T> entry : systemTypeHierarchyList) {

gson/src/test/java/com/google/gson/MemoryRefStackTest.java

@@ -42,7 +42,7 @@ public class MemoryRefStackTest extends TestCase {
   }
 
   public void testPushPeekAndPop() throws Exception {
-    ObjectTypePair obj = new ObjectTypePair(this, getClass(), true);
+    ObjectTypePair obj = new ObjectTypePair(this, getClass(), true, false);
 
     assertEquals(obj, stack.push(obj));
     assertEquals(obj, stack.peek());
@@ -50,7 +50,7 @@ public class MemoryRefStackTest extends TestCase {
   }
 
   public void testPopTooMany() throws Exception {
-    ObjectTypePair obj = new ObjectTypePair(this, getClass(), true);
+    ObjectTypePair obj = new ObjectTypePair(this, getClass(), true, false);
     stack.push(obj);
     assertEquals(obj, stack.pop());
 
@@ -63,9 +63,9 @@ public class MemoryRefStackTest extends TestCase {
     MockObject objA = new MockObject();
     MockObject objB = new MockObject();
     assertEquals(objA, objB);
-    stack.push(new ObjectTypePair(objA, MockObject.class, true));
+    stack.push(new ObjectTypePair(objA, MockObject.class, true, false));
-    assertTrue(stack.contains(new ObjectTypePair(objA, MockObject.class, true)));
+    assertTrue(stack.contains(new ObjectTypePair(objA, MockObject.class, true, false)));
-    assertFalse(stack.contains(new ObjectTypePair(objB, MockObject.class, true)));
+    assertFalse(stack.contains(new ObjectTypePair(objB, MockObject.class, true, false)));
   }
 
   private static class MockObject {

gson/src/test/java/com/google/gson/ParameterizedTypeHandlerMapTest.java

@@ -41,8 +41,8 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
   public void testNullMap() throws Exception {
     assertFalse(paramMap.hasSpecificHandlerFor(String.class));
-    assertNull(paramMap.getHandlerFor(String.class));
+    assertNull(paramMap.getHandlerFor(String.class, false));
-    assertNull(paramMap.getHandlerFor(String.class));
+    assertNull(paramMap.getHandlerFor(String.class, false));
   }
 
   public void testHasGenericButNotSpecific() throws Exception {
@@ -52,9 +52,9 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
     assertFalse(paramMap.hasSpecificHandlerFor(specificType));
     assertTrue(paramMap.hasSpecificHandlerFor(List.class));
-    assertNotNull(paramMap.getHandlerFor(specificType));
+    assertNotNull(paramMap.getHandlerFor(specificType, false));
-    assertNotNull(paramMap.getHandlerFor(List.class));
+    assertNotNull(paramMap.getHandlerFor(List.class, false));
-    assertEquals(handler, paramMap.getHandlerFor(specificType));
+    assertEquals(handler, paramMap.getHandlerFor(specificType, false));
   }
 
   public void testHasSpecificType() throws Exception {
@@ -64,9 +64,9 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
     assertTrue(paramMap.hasSpecificHandlerFor(specificType));
     assertFalse(paramMap.hasSpecificHandlerFor(List.class));
-    assertNotNull(paramMap.getHandlerFor(specificType));
+    assertNotNull(paramMap.getHandlerFor(specificType, false));
-    assertNull(paramMap.getHandlerFor(List.class));
+    assertNull(paramMap.getHandlerFor(List.class, false));
-    assertEquals(handler, paramMap.getHandlerFor(specificType));
+    assertEquals(handler, paramMap.getHandlerFor(specificType, false));
   }
 
   public void testTypeOverridding() throws Exception {
@@ -76,7 +76,7 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
     paramMap.register(String.class, handler2, false);
 
     assertTrue(paramMap.hasSpecificHandlerFor(String.class));
-    assertEquals(handler2, paramMap.getHandlerFor(String.class));
+    assertEquals(handler2, paramMap.getHandlerFor(String.class, false));
   }
 
   public void testMakeUnmodifiable() throws Exception {
@@ -89,14 +89,14 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
   public void testTypeHierarchy() {
     paramMap.registerForTypeHierarchy(Base.class, "baseHandler", false);
-    String handler = paramMap.getHandlerFor(Sub.class);
+    String handler = paramMap.getHandlerFor(Sub.class, false);
     assertEquals("baseHandler", handler);
   }
 
   public void testTypeHierarchyMultipleHandlers() {
     paramMap.registerForTypeHierarchy(Base.class, "baseHandler", false);
     paramMap.registerForTypeHierarchy(Sub.class, "subHandler", false);
-    String handler = paramMap.getHandlerFor(SubOfSub.class);
+    String handler = paramMap.getHandlerFor(SubOfSub.class, false);
     assertEquals("subHandler", handler);
   }
 
@@ -105,14 +105,14 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
     ParameterizedTypeHandlerMap<String> otherMap = new ParameterizedTypeHandlerMap<String>();
     otherMap.registerForTypeHierarchy(Base.class, "baseHandler2", false);
     paramMap.registerIfAbsent(otherMap);
-    String handler = paramMap.getHandlerFor(Base.class);
+    String handler = paramMap.getHandlerFor(Base.class, false);
     assertEquals("baseHandler", handler);
   }
 
   public void testReplaceExistingTypeHierarchyHandler() {
     paramMap.registerForTypeHierarchy(Base.class, "baseHandler", false);
     paramMap.registerForTypeHierarchy(Base.class, "base2Handler", false);
-    String handler = paramMap.getHandlerFor(Base.class);
+    String handler = paramMap.getHandlerFor(Base.class, false);
     assertEquals("base2Handler", handler);
   }
 

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

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.gson.functional;
+
+import java.lang.reflect.Type;
+
+import junit.framework.TestCase;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+
+/**
+ * Functional tests for serialize default behavior where a custom type adapter is allowed to invoke
+ * context.serialize on self.
+ *
+ * @author Inderjeet Singh
+ */
+public class SystemOnlyTypeAdaptersTest extends TestCase {
+
+  private Gson gson;
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    this.gson = new GsonBuilder().registerTypeAdapter(Foo.class, new FooTypeAdapter()).create();
+  }
+
+  public void testSerializeDefault() {
+    String json = gson.toJson(new Foo());
+    assertEquals("{\"a\":10,\"secret-key\":\"abracadabra\"}", json);
+  }
+
+  public void testDeserializeDefault() {
+    String json = "{a:5,'secret-key':'abracadabra'}";
+    Foo foo = gson.fromJson(json, Foo.class);
+    assertEquals(5, foo.a);
+  }
+
+  private static class Foo {
+    int a = 10;
+  }
+
+  private static class FooTypeAdapter implements JsonSerializer<Foo>, JsonDeserializer<Foo> {
+    public JsonElement serialize(Foo src, Type typeOfSrc, JsonSerializationContext context) {
+      JsonObject json = context.serializeDefault(src, typeOfSrc).getAsJsonObject();
+      json.addProperty("secret-key", "abracadabra");
+      return json;
+    }
+
+    public Foo deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+        throws JsonParseException {
+      if (!"abracadabra".equals(json.getAsJsonObject().get("secret-key").getAsString())) {
+        throw new IllegalArgumentException("invalid key");
+      }
+      return context.deserializeDefault(json, typeOfT);
+    }
+  }
+}