Added support for serialization of raw maps.

Also, refactored tests for maps in MapTest class.

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

@@ -18,6 +18,7 @@ package com.google.gson;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -327,10 +328,16 @@ final class DefaultTypeAdapters {
       InstanceCreator<Map> {
     public JsonElement serialize(Map src, Type typeOfSrc, JsonSerializationContext context) {
       JsonObject map = new JsonObject();
-      Type childType = new TypeInfoMap(typeOfSrc).getValueType();
+      Type childGenericType = null;
+      if (typeOfSrc instanceof ParameterizedType) {
+        childGenericType = new TypeInfoMap(typeOfSrc).getValueType();        
+      }
       for (Iterator iterator = src.entrySet().iterator(); iterator.hasNext(); ) {
         Map.Entry entry = (Map.Entry) iterator.next();
-        JsonElement valueElement = context.serialize(entry.getValue(), childType);
+        Object value = entry.getValue();
+        Type childType = (childGenericType == null) ? 
+            childType = value.getClass() : childGenericType;
+        JsonElement valueElement = context.serialize(value, childType);
         map.add(entry.getKey().toString(), valueElement);
       }
       return map;

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

@@ -43,10 +43,10 @@ public class DefaultMapJsonSerializerTest extends TestCase {
 
   public void testEmptyMapNoTypeSerialization() {
     Map<String, String> emptyMap = new HashMap<String, String>();
-    try {
+    JsonElement element = mapSerializer.serialize(emptyMap, emptyMap.getClass(), null);
-      mapSerializer.serialize(emptyMap, emptyMap.getClass(), null);
+    assertTrue(element instanceof JsonObject);
-      fail("Parameterized types need to have a ParameterizedType passed in, not a Class.");
+    JsonObject emptyMapJsonObject = (JsonObject) element;
-    } catch (IllegalArgumentException expected) { }
+    assertTrue(emptyMapJsonObject.entrySet().isEmpty());
   }
 
   public void testEmptyMapSerialization() {

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

@@ -15,14 +15,6 @@
  */
 package com.google.gson.functional;
 
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
-import com.google.gson.JsonParseException;
-import com.google.gson.reflect.TypeToken;
-
-import junit.framework.TestCase;
-
-import java.lang.reflect.Type;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.net.URI;
@@ -31,14 +23,18 @@ import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.HashSet;
-import java.util.LinkedHashMap;
 import java.util.Locale;
-import java.util.Map;
 import java.util.Set;
 
+import junit.framework.TestCase;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonParseException;
+
 /**
  * Functional test for Json serialization and deserialization for common classes for which default
- * support is provided in Gson.
+ * support is provided in Gson. The tests for Map types are available in {@link MapTest}.
  *
  * @author Inderjeet Singh
  * @author Joel Leitch
@@ -114,31 +110,6 @@ public class DefaultTypeAdaptersTest extends TestCase {
     assertEquals("EURO", locale.getVariant());
   }
 
-  public void testMapSerialization() {
-    Map<String, Integer> map = new LinkedHashMap<String, Integer>();
-    map.put("a", 1);
-    map.put("b", 2);
-    Type typeOfMap = new TypeToken<Map<String, Integer>>() {}.getType();
-    String json = gson.toJson(map, typeOfMap);
-    assertTrue(json.contains("\"a\":1"));
-    assertTrue(json.contains("\"b\":2"));
-  }
-
-  public void testMapDeserialization() {
-    String json = "{\"a\":1,\"b\":2}";
-    Type typeOfMap = new TypeToken<Map<String,Integer>>(){}.getType();
-    Map<String, Integer> target = gson.fromJson(json, typeOfMap);
-    assertEquals(1, target.get("a").intValue());
-    assertEquals(2, target.get("b").intValue());
-  }
-
-  public void testMapSerializationEmpty() {
-    Map<String, Integer> map = new LinkedHashMap<String, Integer>();
-    Type typeOfMap = new TypeToken<Map<String, Integer>>() {}.getType();
-    String json = gson.toJson(map, typeOfMap);
-    assertEquals("{}", json);
-  }
-
   public void testBigDecimalFieldSerialization() {
     ClassWithBigDecimal target = new ClassWithBigDecimal("-122.01e-21");
     String json = gson.toJson(target);

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

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2008 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 java.util.LinkedHashMap;
+import java.util.Map;
+
+import junit.framework.TestCase;
+
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+
+/**
+ * Functional test for Json serialization and deserialization for Maps
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public class MapTest extends TestCase {
+  private Gson gson;
+
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    gson = new Gson();
+  }
+
+  public void testMapSerialization() {
+    Map<String, Integer> map = new LinkedHashMap<String, Integer>();
+    map.put("a", 1);
+    map.put("b", 2);
+    Type typeOfMap = new TypeToken<Map<String, Integer>>() {}.getType();
+    String json = gson.toJson(map, typeOfMap);
+    assertTrue(json.contains("\"a\":1"));
+    assertTrue(json.contains("\"b\":2"));
+  }
+
+  public void testMapDeserialization() {
+    String json = "{\"a\":1,\"b\":2}";
+    Type typeOfMap = new TypeToken<Map<String,Integer>>(){}.getType();
+    Map<String, Integer> target = gson.fromJson(json, typeOfMap);
+    assertEquals(1, target.get("a").intValue());
+    assertEquals(2, target.get("b").intValue());
+  }
+
+  @SuppressWarnings("unchecked")
+  public void testRawMapSerialization() {
+    Map map = new LinkedHashMap();
+    map.put("a", 1);
+    map.put("b", "string");
+    String json = gson.toJson(map);
+    assertTrue(json.contains("\"a\":1"));
+    assertTrue(json.contains("\"b\":\"string\""));    
+  }
+  
+  public void testMapSerializationEmpty() {
+    Map<String, Integer> map = new LinkedHashMap<String, Integer>();
+    Type typeOfMap = new TypeToken<Map<String, Integer>>() {}.getType();
+    String json = gson.toJson(map, typeOfMap);
+    assertEquals("{}", json);
+  }
+}