Code cleanup and some minor performance fixes.

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

@@ -454,8 +454,8 @@ final class DefaultTypeAdapters {
         if (value == null) {
           valueElement = JsonNull.createJsonNull();
         } else {
-          Type childType = (childGenericType == null) ? 
-              childType = value.getClass() : childGenericType;
+          Type childType = (childGenericType == null)
+              ? value.getClass() : childGenericType;
           valueElement = context.serialize(value, childType);
         }
         map.add(String.valueOf(entry.getKey()), valueElement);

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

@@ -26,7 +26,6 @@ import java.lang.reflect.Type;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.logging.Logger;
 
 /**
  * This is the main class for using Gson. Gson is typically used by first constructing a
@@ -76,6 +75,7 @@ public final class Gson {
   // constructor instead. At the minimum, mark those methods private.
 
   private static final String NULL_STRING = "null";
+
   // Default instances of plug-ins
   static final ModifierBasedExclusionStrategy DEFAULT_MODIFIER_BASED_EXCLUSION_STRATEGY =
       new ModifierBasedExclusionStrategy(true, new int[] { Modifier.TRANSIENT, Modifier.STATIC });
@@ -83,8 +83,6 @@ public final class Gson {
   static final FieldNamingStrategy DEFAULT_NAMING_POLICY =
       new SerializedNameAnnotationInterceptingNamingPolicy(new JavaFieldNamingPolicy());
 
-  static final Logger logger = Logger.getLogger(Gson.class.getName());
-
   private final ExclusionStrategy strategy;
   private final FieldNamingStrategy fieldNamingPolicy;
   private final MappedObjectConstructor objectConstructor;
@@ -402,15 +400,16 @@ public final class Gson {
   
   @Override 
   public String toString() {
-	StringBuilder sb = new StringBuilder("{");
-    sb.append("serializeNulls:").append(serializeNulls);
-	sb.append(",serializers:").append(serializers);
-	sb.append(",deserializers:").append(deserializers);
-	// using the name instanceCreator instead of ObjectConstructor since the users of Gson are 
-	// more familiar with the concept of Instance Creators. Moreover, the objectConstructor is
-	// just a utility class around instance creators, and its toString() only displays them.
-    sb.append(",instanceCreators:").append(objectConstructor);
-	sb.append("}");
-	return sb.toString();
+  	StringBuilder sb = new StringBuilder("{")
+  	    .append("serializeNulls:").append(serializeNulls)
+  	    .append(",serializers:").append(serializers)
+  	    .append(",deserializers:").append(deserializers)
+  	
+      	// using the name instanceCreator instead of ObjectConstructor since the users of Gson are 
+      	// more familiar with the concept of Instance Creators. Moreover, the objectConstructor is
+      	// just a utility class around instance creators, and its toString() only displays them.
+        .append(",instanceCreators:").append(objectConstructor)
+        .append("}");
+  	return sb.toString();
   }
 }

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

@@ -436,8 +436,8 @@ public final class GsonBuilder {
       dateTypeAdapter = new DefaultDateTypeAdapter(dateStyle, timeStyle);
     }
     if (dateTypeAdapter != null
-        && !serializers.hasAnyHandlerFor(Date.class)
-        && !deserializers.hasAnyHandlerFor(Date.class)) {
+        && !serializers.hasSpecificHandlerFor(Date.class)
+        && !deserializers.hasSpecificHandlerFor(Date.class)) {
       serializers.register(Date.class, dateTypeAdapter);
       deserializers.register(Date.class, dateTypeAdapter);
     }

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

@@ -16,6 +16,7 @@
 
 package com.google.gson;
 
+import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.Collections;
@@ -291,7 +292,7 @@ public final class JsonArray extends JsonElement implements Iterable<JsonElement
   }
 
   @Override
-  protected void toString(StringBuilder sb) {
+  protected void toString(Appendable sb) throws IOException {
     sb.append('[');
     boolean first = true;
     for (JsonElement element : elements) {

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

@@ -35,7 +35,7 @@ final class JsonCompactFormatter implements JsonFormatter {
     }
 
     public void visitPrimitive(JsonPrimitive primitive) throws IOException {
-      writer.append(primitive.toString());
+      primitive.toString(writer);
     }
 
     public void visitNull() throws IOException {
@@ -51,7 +51,7 @@ final class JsonCompactFormatter implements JsonFormatter {
       if (!isFirst) {
         writer.append(',');
       }
-      writer.append(member.toString());
+      member.toString(writer);
     }
 
     public void visitArrayMember(JsonArray parent, JsonArray member, 
@@ -90,7 +90,7 @@ final class JsonCompactFormatter implements JsonFormatter {
       writer.append('"');
       writer.append(memberName);
       writer.append("\":");
-      writer.append(member.toString());
+      member.toString(writer);
     }
 
     public void visitObjectMember(JsonObject parent, String memberName, JsonArray member,

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

@@ -17,7 +17,6 @@
 package com.google.gson;
 
 import java.lang.reflect.Type;
-import java.util.logging.Logger;
 
 /**
  * Abstract data value container for the {@link ObjectNavigator.Visitor}
@@ -29,8 +28,6 @@ import java.util.logging.Logger;
  */
 abstract class JsonDeserializationVisitor<T> implements ObjectNavigator.Visitor {
 
-  protected static Logger logger = Logger.getLogger(JsonDeserializationVisitor.class.getName());
-
   protected final ObjectNavigatorFactory factory;
   protected final ObjectConstructor objectConstructor;
   protected final ParameterizedTypeHandlerMap<JsonDeserializer<?>> deserializers;

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

@@ -16,6 +16,7 @@
 
 package com.google.gson;
 
+import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
@@ -311,10 +312,14 @@ public abstract class JsonElement {
    */
   @Override
   public String toString() {
-    StringBuilder sb = new StringBuilder();
-    toString(sb);
-    return sb.toString();
+    try {
+      StringBuilder sb = new StringBuilder();
+      toString(sb);
+      return sb.toString();
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
   }
 
-  protected abstract void toString(StringBuilder sb);
+  protected abstract void toString(Appendable sb) throws IOException;
 }

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

@@ -61,10 +61,7 @@ class JsonEscapingVisitor extends DelegatingJsonElementVisitor {
   private JsonPrimitive escapeJsonPrimitive(JsonPrimitive member) {
     if (member.isString()) {
       String memberValue = member.getAsString();
-      String escapedValue = escaper.escapeJsonString(memberValue);
-      if (!escapedValue.equals(memberValue)) {
-        member.setValue(escapedValue);
-      }
+      member.setValue(escaper.escapeJsonString(memberValue));
     }
     return member;
   }

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

@@ -16,6 +16,8 @@
 
 package com.google.gson;
 
+import java.io.IOException;
+
 /**
  * A class representing a Json {@code null} value.
  *
@@ -34,7 +36,7 @@ public final class JsonNull extends JsonElement {
   }
   
   @Override
-  protected void toString(StringBuilder sb) {
+  protected void toString(Appendable sb) throws IOException {
     sb.append("null");
   }
   

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

@@ -16,6 +16,7 @@
 
 package com.google.gson;
 
+import java.io.IOException;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
@@ -189,7 +190,7 @@ public final class JsonObject extends JsonElement {
   }
 
   @Override
-  protected void toString(StringBuilder sb) {
+  protected void toString(Appendable sb) throws IOException {
     sb.append('{');
     boolean first = true;
     for (Map.Entry<String, JsonElement> entry : members.entrySet()) {

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

@@ -16,6 +16,7 @@
 
 package com.google.gson;
 
+import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
@@ -305,16 +306,13 @@ public final class JsonPrimitive extends JsonElement {
   }
 
   @Override
-  protected void toString(StringBuilder sb) {
-    if (value != null) {
-      if (value instanceof String) {
-        sb.append('"');
-        sb.append(value);
-        sb.append('"');
-
-      } else {
-        sb.append(value);
-      }
+  protected void toString(Appendable sb) throws IOException {
+    if (value instanceof String) {
+      sb.append('"');
+      sb.append((String) value);
+      sb.append('"');
+    } else {
+      sb.append(value.toString());
     }
   }
   

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

@@ -103,17 +103,13 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
 
   private void addAsArrayElement(Type elementType, Object elementValue) {
     if (elementValue == null) {
-      addNullAsArrayElement();
+      root.getAsJsonArray().add(JsonNull.createJsonNull());
     } else {
       JsonElement childElement = getJsonElementForChild(elementType, elementValue);
       root.getAsJsonArray().add(childElement);
     }
   }
 
-  private void addNullAsArrayElement() {
-    root.getAsJsonArray().add(null);
-  }
-
   private JsonElement getJsonElementForChild(Type fieldType, Object fieldValue) {
     ObjectNavigator on = factory.create(fieldValue, fieldType);
     JsonSerializationVisitor childVisitor =
@@ -160,7 +156,7 @@ final class JsonSerializationVisitor implements ObjectNavigator.Visitor {
   }
 
   private void assignToRoot(JsonElement newRoot) {
-    Preconditions.checkArgument(root == null);
+    Preconditions.checkNotNull(newRoot);
     root = newRoot;
   }
 

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

@@ -34,7 +34,7 @@ final class JsonTreeNavigator {
   }
   
   public void navigate(JsonElement element) throws IOException {
-    if (element == null || element.isJsonNull()) {
+    if (element.isJsonNull()) {
       visitor.visitNull();
     } else if (element.isJsonArray()) {
       JsonArray array = element.getAsJsonArray();
@@ -68,25 +68,23 @@ final class JsonTreeNavigator {
    */
   private boolean visitChild(JsonObject parent, String childName, JsonElement child, 
       boolean isFirst) throws IOException {
-    if (child != null) { 
-      if (child.isJsonNull()) {
-        if (visitNulls) {
-          visitor.visitNullObjectMember(parent, childName, isFirst);
-          navigate(child.getAsJsonNull());
-        } else { // Null value is being skipped.
-          return false;
-        }
-      } else if (child.isJsonArray()) {
-        JsonArray childAsArray = child.getAsJsonArray();
-        visitor.visitObjectMember(parent, childName, childAsArray, isFirst);
-        navigate(childAsArray);
-      } else if (child.isJsonObject()) {
-        JsonObject childAsObject = child.getAsJsonObject();
-        visitor.visitObjectMember(parent, childName, childAsObject, isFirst);
-        navigate(childAsObject);
-      } else { // is a JsonPrimitive
-        visitor.visitObjectMember(parent, childName, child.getAsJsonPrimitive(), isFirst);          
+    if (child.isJsonNull()) {
+      if (visitNulls) {
+        visitor.visitNullObjectMember(parent, childName, isFirst);
+        navigate(child.getAsJsonNull());
+      } else { // Null value is being skipped.
+        return false;
       }
+    } else if (child.isJsonArray()) {
+      JsonArray childAsArray = child.getAsJsonArray();
+      visitor.visitObjectMember(parent, childName, childAsArray, isFirst);
+      navigate(childAsArray);
+    } else if (child.isJsonObject()) {
+      JsonObject childAsObject = child.getAsJsonObject();
+      visitor.visitObjectMember(parent, childName, childAsObject, isFirst);
+      navigate(childAsObject);
+    } else { // is a JsonPrimitive
+      visitor.visitObjectMember(parent, childName, child.getAsJsonPrimitive(), isFirst);          
     }
     return true;
   }
@@ -95,9 +93,9 @@ final class JsonTreeNavigator {
    * Returns true if the child was visited, false if it was skipped.
    */
   private void visitChild(JsonArray parent, JsonElement child, boolean isFirst) throws IOException {
-    if (child == null || child.isJsonNull()) {
+    if (child.isJsonNull()) {
       visitor.visitNullArrayMember(parent, isFirst);
-      navigate(null);
+      navigate(child);
 	} else if (child.isJsonArray()) {
       JsonArray childAsArray = child.getAsJsonArray();
       visitor.visitArrayMember(parent, childAsArray, isFirst);

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

@@ -35,15 +35,15 @@ import java.util.logging.Logger;
  * @author Joel Leitch
  */
 final class MappedObjectConstructor implements ObjectConstructor {
-  private final Logger log = Logger.getLogger(getClass().getName());
+  private static final Logger log = Logger.getLogger(MappedObjectConstructor.class.getName());
 
   private final ParameterizedTypeHandlerMap<InstanceCreator<?>> instanceCreatorMap =
-    new ParameterizedTypeHandlerMap<InstanceCreator<?>>();
+      new ParameterizedTypeHandlerMap<InstanceCreator<?>>();
 
   @SuppressWarnings("unchecked")
   public <T> T construct(Type typeOfT) {
-    if (instanceCreatorMap.hasAnyHandlerFor(typeOfT)) {
-      InstanceCreator<T> creator = (InstanceCreator<T>) instanceCreatorMap.getHandlerFor(typeOfT);
+    InstanceCreator<T> creator = (InstanceCreator<T>) instanceCreatorMap.getHandlerFor(typeOfT);
+    if (creator != null) {
       return creator.createInstance(typeOfT);
     }
     return (T) constructWithNoArgConstructor(typeOfT);

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

@@ -16,40 +16,46 @@
 
 package com.google.gson;
 
-import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /**
- * A map that provides ability to associate handlers for a specific type or all of its sub-types
- *
+ * A map that provides ability to associate handlers for a specific type or all
+ * of its sub-types
+ * 
  * @author Inderjeet Singh
  * @author Joel Leitch
- *
- * @param <T> The handler that will be looked up by type
+ * 
+ * @param <T>
+ *          The handler that will be looked up by type
  */
 final class ParameterizedTypeHandlerMap<T> {
-
+  private static final Logger logger =
+      Logger.getLogger(ParameterizedTypeHandlerMap.class.getName());
   private final Map<Type, T> map = new HashMap<Type, T>();
   private boolean modifiable = true;
 
   public synchronized void register(Type typeOfT, T value) {
     if (!modifiable) {
-      throw new IllegalStateException("Attempted to modify an unmodifiable map.");
+      throw new IllegalStateException(
+          "Attempted to modify an unmodifiable map.");
     }
     if (hasSpecificHandlerFor(typeOfT)) {
-      Gson.logger.log(Level.WARNING, "Overriding the existing type handler for " + typeOfT);
+      logger.log(Level.WARNING,
+          "Overriding the existing type handler for " + typeOfT);
     }
     map.put(typeOfT, value);
   }
 
   public synchronized void registerIfAbsent(ParameterizedTypeHandlerMap<T> other) {
     if (!modifiable) {
-      throw new IllegalStateException("Attempted to modify an unmodifiable map.");
+      throw new IllegalStateException(
+          "Attempted to modify an unmodifiable map.");
     }
     for (Map.Entry<Type, T> entry : other.entrySet()) {
       if (!map.containsKey(entry.getKey())) {
@@ -60,7 +66,8 @@ final class ParameterizedTypeHandlerMap<T> {
 
   public synchronized void registerIfAbsent(Type typeOfT, T value) {
     if (!modifiable) {
-      throw new IllegalStateException("Attempted to modify an unmodifiable map.");
+      throw new IllegalStateException(
+          "Attempted to modify an unmodifiable map.");
     }
     if (!map.containsKey(typeOfT)) {
       register(typeOfT, value);
@@ -72,18 +79,15 @@ final class ParameterizedTypeHandlerMap<T> {
   }
 
   public synchronized T getHandlerFor(Type type) {
-    T handler = getRawHandlerFor(type);
-    Type rawType = type;
-    if (handler == null && type instanceof ParameterizedType) {
-      // a handler for a non-generic version may be registered, so use that
-      rawType = ((ParameterizedType)type).getRawType();
-      handler = map.get(rawType);
-    }
-
-    // Check for map or collection 
+    T handler = map.get(type);
     if (handler == null) {
-      if (rawType instanceof Class) {
-        Class<?> rawClass = (Class<?>) rawType;
+      Class<?> rawClass = TypeUtils.toRawClass(type);
+      if (rawClass != type) {
+        handler = getHandlerFor(rawClass);
+      }
+
+      // Check for map or collection
+      if (handler == null) {
         if (Map.class.isAssignableFrom(rawClass)) {
           handler = map.get(Map.class);
         } else if (Collection.class.isAssignableFrom(rawClass)) {
@@ -95,27 +99,6 @@ final class ParameterizedTypeHandlerMap<T> {
     }
     return handler;
   }
-  
-  private synchronized T getRawHandlerFor(Type type) {
-    if (type instanceof Map) {
-      return map.get(Map.class);
-    } else if (type instanceof Collection) {
-      return map.get(Collection.class);
-    } else {
-      T handler = map.get(type);
-      if (handler == null) {
-        Class<?> rawClass = TypeUtils.toRawClass(type);
-        if (rawClass != type) {
-          handler = getHandlerFor(rawClass);
-        }
-      }
-      return handler;
-    }
-  }
-
-  public synchronized boolean hasAnyHandlerFor(Type type) {
-    return getHandlerFor(type) != null;
-  }
 
   public synchronized boolean hasSpecificHandlerFor(Type type) {
     return map.containsKey(type);
@@ -132,7 +115,7 @@ final class ParameterizedTypeHandlerMap<T> {
   public synchronized Set<Map.Entry<Type, T>> entrySet() {
     return map.entrySet();
   }
-  
+
   @Override
   public String toString() {
     StringBuilder sb = new StringBuilder("{");
@@ -148,7 +131,7 @@ final class ParameterizedTypeHandlerMap<T> {
     }
     return sb.toString();
   }
-  
+
   private String typeToString(Type type) {
     return TypeUtils.toRawClass(type).getSimpleName();
   }

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

@@ -39,7 +39,7 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
   public void testNullMap() throws Exception {
     assertFalse(paramMap.hasSpecificHandlerFor(String.class));
-    assertFalse(paramMap.hasAnyHandlerFor(String.class));
+    assertNull(paramMap.getHandlerFor(String.class));
     assertNull(paramMap.getHandlerFor(String.class));
   }
 
@@ -50,8 +50,8 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
     assertFalse(paramMap.hasSpecificHandlerFor(specificType));
     assertTrue(paramMap.hasSpecificHandlerFor(List.class));
-    assertTrue(paramMap.hasAnyHandlerFor(specificType));
-    assertTrue(paramMap.hasAnyHandlerFor(List.class));
+    assertNotNull(paramMap.getHandlerFor(specificType));
+    assertNotNull(paramMap.getHandlerFor(List.class));
     assertEquals(handler, paramMap.getHandlerFor(specificType));
   }
 
@@ -62,8 +62,8 @@ public class ParameterizedTypeHandlerMapTest extends TestCase {
 
     assertTrue(paramMap.hasSpecificHandlerFor(specificType));
     assertFalse(paramMap.hasSpecificHandlerFor(List.class));
-    assertTrue(paramMap.hasAnyHandlerFor(specificType));
-    assertFalse(paramMap.hasAnyHandlerFor(List.class));
+    assertNotNull(paramMap.getHandlerFor(specificType));
+    assertNull(paramMap.getHandlerFor(List.class));
     assertEquals(handler, paramMap.getHandlerFor(specificType));
   }
 

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

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package com.google.gson.functional;
 
 import com.google.gson.Gson;
@@ -82,6 +83,14 @@ public class ArrayTest extends TestCase {
       assertEquals(expected[i], target[i]);
     }
   }
+  
+  public void testNullsInArrayWithSerializeNullPropertySetSerialization() {
+    gson = new GsonBuilder().serializeNulls().create();
+    String[] array = {"foo", null, "bar"};
+    String expected = "[\"foo\",null,\"bar\"]";
+    String json = gson.toJson(array);
+    assertEquals(expected, json);
+  }
 
   public void testArrayOfStringsSerialization() {
     String[] target = {"Hello", "World"};