Created a generalized key-value store,MetaDataMap, for a map of MetaData.

Moved MetaData to wsdef from wsf.
Added a Gson type adapter for Id type.

wsdef/src/main/java/com/google/gson/webservice/definition/rest/MetaData.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2010 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.webservice.definition.rest;
+
+import java.lang.reflect.Type;
+import java.util.HashMap;
+import java.util.Map;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.reflect.TypeToken;
+
+/**
+ * Metadata associated with a repository for a rest resource
+ *
+ * @author inder
+ *
+ * @param <R> The resource
+ */
+public final class MetaData<R extends RestResource<R>> {
+
+  private final Map<String, String> map;
+
+  public static <RS extends RestResource<RS>> MetaData<RS> create() {
+    return new MetaData<RS>();
+  }
+
+  @SuppressWarnings({"unchecked", "rawtypes"})
+  private static MetaData<?> createTypeUnsafe(Map<String, String> values) {
+    return new MetaData(values);
+  }
+
+  public MetaData() {
+    this(new HashMap<String, String>());
+  }
+
+  private MetaData(Map<String, String> values) {
+    this.map = values;
+  }
+
+  public String getString(String key) {
+    return (String) map.get(key);
+  }
+
+  public void putString(String key, String value) {
+    map.put(key, value);
+  }
+
+  public boolean getBoolean(String key) {
+    String value = map.get(key);
+    return value == null ? false : Boolean.parseBoolean(value);
+  }
+
+  public void putBoolean(String key, boolean value) {
+    map.put(key, String.valueOf(value));
+  }
+
+  public void remove(String key) {
+    map.remove(key);
+  }
+
+  /**
+   * Gson Type adapter for {@link MetaData}. The serialized representation on wire is just a
+   * Map<String, String>
+   */
+  public static final class GsonTypeAdapter implements JsonSerializer<MetaData<?>>,
+    JsonDeserializer<MetaData<?>>{
+
+    private static final Type MAP_TYPE = new TypeToken<Map<String, String>>(){}.getType();
+
+    @Override
+    public MetaData<?> deserialize(JsonElement json, Type typeOfT,
+        JsonDeserializationContext context) throws JsonParseException {
+      Map<String, String> map = context.deserialize(json, MAP_TYPE);
+      return MetaData.createTypeUnsafe(map);
+    }
+
+    @Override
+    public JsonElement serialize(MetaData<?> src, Type typeOfSrc,
+        JsonSerializationContext context) {
+      return context.serialize(src.map, MAP_TYPE);
+    }
+  }
+}

wsdef/src/main/java/com/google/gson/webservice/definition/rest/RestResource.java

@@ -23,5 +23,4 @@ package com.google.gson.webservice.definition.rest;
  * @param <R> the rest resource type
  */
 public interface RestResource<R> extends HasId<R> {
-
 }

wsdef/src/main/java/com/google/gson/webservice/typeadapters/IdTypeAdapter.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2010 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.webservice.typeadapters;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.webservice.definition.rest.Id;
+
+/**
+ * Type adapter for converting an Id to its serialized form
+ *
+ * @author inder
+ *
+ */
+public final class IdTypeAdapter implements JsonSerializer<Id<?>>, JsonDeserializer<Id<?>> {
+
+  @Override
+  public JsonElement serialize(Id<?> src, Type typeOfSrc, JsonSerializationContext context) {
+    return new JsonPrimitive(src.getValue());
+  }
+
+  @Override
+  public Id<?> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+      throws JsonParseException {
+    if (!(typeOfT instanceof ParameterizedType)) {
+      throw new JsonParseException("Id of unknown type: " + typeOfT);
+    }
+    ParameterizedType parameterizedType = (ParameterizedType) typeOfT;
+    // Since Id takes only one TypeVariable, the actual type corresponding to the first
+    // TypeVariable is the Type we are looking for
+    Type typeOfId = parameterizedType.getActualTypeArguments()[0];
+    return Id.get(json.getAsLong(), typeOfId);
+  }
+}

wsdef/src/test/java/com/google/gson/webservice/typeadapters/IdTypeAdapterTest.java

@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2010 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.webservice.typeadapters;
+
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import junit.framework.TestCase;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.webservice.definition.rest.Id;
+
+/**
+ * Unit tests for {@link IdTypeAdapter}
+ *
+ * @author inder
+ */
+public class IdTypeAdapterTest extends TestCase {
+  private static final Id<Student> STUDENT1_ID = Id.get(5L, Student.class);
+  private static final Id<Student> STUDENT2_ID = Id.get(6L, Student.class);
+  private static final Student STUDENT1 = new Student(STUDENT1_ID, "first");
+  private static final Student STUDENT2 = new Student(STUDENT2_ID, "second");
+  private static final Type TYPE_COURSE_HISTORY =
+    new TypeToken<Course<HistoryCourse>>(){}.getType(); 
+  private static final Id<Course<HistoryCourse>> COURSE_ID = Id.get(10L, TYPE_COURSE_HISTORY);
+
+  private Gson gson;
+  private Course<HistoryCourse> course;
+
+  @Override
+  protected void setUp() {
+    gson = new GsonBuilder()
+        .registerTypeAdapter(Id.class, new IdTypeAdapter())
+        .create();
+    course = new Course<HistoryCourse>(COURSE_ID, 4,
+        new Assignment<HistoryCourse>(null, null), createList(STUDENT1, STUDENT2));
+  }
+
+  public void testSerializeId() {
+    String json = gson.toJson(course, TYPE_COURSE_HISTORY);
+    System.out.println(json);
+    assertTrue(json.contains(String.valueOf(COURSE_ID.getValue())));
+    assertTrue(json.contains(String.valueOf(STUDENT1_ID.getValue())));
+    assertTrue(json.contains(String.valueOf(STUDENT2_ID.getValue())));
+  }
+
+  public void testDeserializeId() {
+    String json = "{courseId:1,students:[{id:1,name:'first'},{id:6,name:'second'}],"
+      + "numAssignments:4,assignment:{}}";
+    Course<HistoryCourse> target = gson.fromJson(json, TYPE_COURSE_HISTORY);
+    assertEquals(1, target.getStudents().get(0).id.getValue());
+    assertEquals(6, target.getStudents().get(1).id.getValue());
+    assertEquals(1, target.getId().getValue());
+  }
+
+  @SuppressWarnings("unused")
+  private static class Student {
+    Id<Student> id;
+    String name;
+
+    private Student() {
+      this(null, null);
+    }
+    public Student(Id<Student> id, String name) {
+      this.id = id;
+      this.name = name;
+    }
+  }
+  @SuppressWarnings("unused")
+  private static class Course<T> {
+    final List<Student> students;
+    private final Id<Course<T>> courseId;
+    private final int numAssignments;
+    private final Assignment<T> assignment;
+
+    private Course() {
+      this(null, 0, null, new ArrayList<Student>());
+    }
+
+    public Course(Id<Course<T>> courseId, int numAssignments,
+        Assignment<T> assignment, List<Student> players) {
+      this.courseId = courseId;
+      this.numAssignments = numAssignments;
+      this.assignment = assignment;
+      this.students = players;
+    }
+    public Id<Course<T>> getId() {
+      return courseId;
+    }
+    List<Student> getStudents() {
+      return students;
+    }
+  }
+
+  @SuppressWarnings("unused")
+  private static class Assignment<T> {
+    private final Id<Assignment<T>> id;
+    private final T data;
+
+    private Assignment() {
+      this(null, null);
+    }
+    public Assignment(Id<Assignment<T>> id, T data) {
+      this.id = id;
+      this.data = data;
+    }
+  }
+
+  @SuppressWarnings("unused")
+  private static class HistoryCourse {
+    int numClasses;
+  }
+
+  private static <T> List<T> createList(T ...items) {
+    return Arrays.asList(items);
+  }
+}

wsf/src/main/java/com/google/gson/wsf/server/rest/MetaDataMap.java

@@ -15,24 +15,33 @@
  */
 package com.google.gson.wsf.server.rest;
 
+import java.util.HashMap;
+import java.util.Map;
+
+import com.google.gson.webservice.definition.rest.Id;
+import com.google.gson.webservice.definition.rest.MetaData;
 import com.google.gson.webservice.definition.rest.RestResource;
 
 /**
- * Metadata associated with a repository for a rest resource
+ * A map of resources to their MetaData
  *
  * @author inder
  *
- * @param <R> The resource
+ * @param <R> the rest resource for whic the metadata is being stored
  */
-public final class MetaData<R extends RestResource<R>> {
+public class MetaDataMap<R extends RestResource<R>> {
+  private final Map<Id<R>, MetaData<R>> map;
 
-  final boolean freshlyAssignedId;
-
-  public MetaData(boolean freshlyAssignedId) {
-    this.freshlyAssignedId = freshlyAssignedId;
+  public MetaDataMap() {
+    this.map = new HashMap<Id<R>, MetaData<R>>();
   }
 
-  public boolean isFreshlyAssignedId() {
-    return freshlyAssignedId;
+  public MetaData<R> get(Id<R> resourceId) {
+    MetaData<R> metaData = map.get(resourceId);
+    if (metaData == null) {
+      metaData = MetaData.create();
+      map.put(resourceId, metaData);
+    }
+    return metaData;
   }
-}
+}

wsf/src/main/java/com/google/gson/wsf/server/rest/RepositoryInMemory.java

@@ -18,6 +18,7 @@ package com.google.gson.wsf.server.rest;
 import java.util.Map;
 
 import com.google.gson.webservice.definition.rest.Id;
+import com.google.gson.webservice.definition.rest.MetaData;
 import com.google.gson.webservice.definition.rest.RestResource;
 import com.google.inject.internal.Maps;
 import com.google.inject.internal.Preconditions;
@@ -30,12 +31,14 @@ import com.google.inject.internal.Preconditions;
  * @param <R> Type variable for the resource
  */
 public class RepositoryInMemory<R extends RestResource<R>> implements Repository<R> {
+  private static final String METADATA_KEY_IS_FRESHLY_ASSIGNED_ID = "isFreshlyAssignedId";
+
   private final IdMap<R> resources;
-  private final Map<Id<R>, MetaData<R>> metaDataMap;
+  private final MetaDataMap<R> metaDataMap;
 
   public RepositoryInMemory(Class<? super R> classOfResource) {
     this.resources = IdMap.create(classOfResource);
-    this.metaDataMap = Maps.newHashMap();
+    this.metaDataMap = new MetaDataMap<R>();
   }
 
   @Override
@@ -48,7 +51,7 @@ public class RepositoryInMemory<R extends RestResource<R>> implements Repository
     if (metaData == null) {
       return false;
     }
-    return metaData.isFreshlyAssignedId();
+    return metaData.getBoolean(METADATA_KEY_IS_FRESHLY_ASSIGNED_ID);
   }
 
   @Override
@@ -64,7 +67,7 @@ public class RepositoryInMemory<R extends RestResource<R>> implements Repository
       }
     }
     resource = resources.put(resource);
-    metaDataMap.remove(resource.getId());
+    metaDataMap.get(resource.getId()).remove(METADATA_KEY_IS_FRESHLY_ASSIGNED_ID);
     return resource;
   }
 
@@ -88,7 +91,7 @@ public class RepositoryInMemory<R extends RestResource<R>> implements Repository
     if (resource.getId() == null) {
       Id<R> id = resources.getNextId();
       resource.setId(id);
-      metaDataMap.put(id, new MetaData<R>(true));
+      metaDataMap.get(id).putBoolean(METADATA_KEY_IS_FRESHLY_ASSIGNED_ID, true);
     }
     return resource.getId();
   }