Update GsonBuilder API to accept an enum for the serialize Long as string. This will be useful if/when we implement support to serialize a long type as an array of integers.

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

@@ -186,11 +186,11 @@ final class DefaultTypeAdapters {
   }
 
   static ParameterizedTypeHandlerMap<JsonSerializer<?>> getDefaultSerializers() {
-    return getDefaultSerializers(false, false);
+    return getDefaultSerializers(false, LongSerializationPolicy.DEFAULT);
   }
       
   static ParameterizedTypeHandlerMap<JsonSerializer<?>> getDefaultSerializers(
-      boolean serializeSpecialFloatingPointValues, boolean serializeLongsAsString) {
+      boolean serializeSpecialFloatingPointValues, LongSerializationPolicy longSerializationPolicy) {
     ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers =
         new ParameterizedTypeHandlerMap<JsonSerializer<?>>();
     
@@ -208,7 +208,7 @@ final class DefaultTypeAdapters {
 
     // Long primitive
     DefaultTypeAdapters.LongSerializer longSerializer = 
-        new DefaultTypeAdapters.LongSerializer(serializeLongsAsString);
+        new DefaultTypeAdapters.LongSerializer(longSerializationPolicy);
     serializers.registerIfAbsent(Long.class, longSerializer);
     serializers.registerIfAbsent(long.class, longSerializer);
 
@@ -564,20 +564,14 @@ final class DefaultTypeAdapters {
   }
   
   private static class LongSerializer implements JsonSerializer<Long> {
-    private final boolean serializeAsString;
+    private final LongSerializationPolicy longSerializationPolicy;
     
-    private LongSerializer(boolean serializeAsString) {
+    private LongSerializer(LongSerializationPolicy longSerializationPolicy) {
-      this.serializeAsString = serializeAsString;
+      this.longSerializationPolicy = longSerializationPolicy;
     }
 
     public JsonElement serialize(Long src, Type typeOfSrc, JsonSerializationContext context) {
-      if (src == null) {
+      return longSerializationPolicy.serialize(src);
-        return JsonNull.createJsonNull();
-      } else if (serializeAsString) {
-        return new JsonPrimitive(String.valueOf(src));
-      } else {
-        return new JsonPrimitive(src);
-      }
     }
 
     @Override

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

@@ -16,14 +16,14 @@
 
 package com.google.gson;
 
-import com.google.gson.DefaultTypeAdapters.DefaultDateTypeAdapter;
-
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.util.Date;
 import java.util.LinkedList;
 import java.util.List;
 
+import com.google.gson.DefaultTypeAdapters.DefaultDateTypeAdapter;
+
 /**
  * <p>Use this builder to construct a {@link Gson} instance when you need to set configuration
  * options other than the default. For {@link Gson} with default configuration, it is simpler to
@@ -52,12 +52,12 @@ import java.util.List;
 public final class GsonBuilder {
 
   private double ignoreVersionsAfter;
-  private boolean serializeLongAsString;
   private ModifierBasedExclusionStrategy modifierBasedExclusionStrategy;
   private boolean serializeInnerClasses;
   private final AnonymousAndLocalClassExclusionStrategy anonAndLocalClassExclusionStrategy;
   private final InnerClassExclusionStrategy innerClassExclusionStrategy;
   private boolean excludeFieldsWithoutExposeAnnotation;
+  private LongSerializationPolicy longSerializationPolicy;
   private FieldNamingStrategy fieldNamingPolicy;
   private final ParameterizedTypeHandlerMap<InstanceCreator<?>> instanceCreators;
   private final ParameterizedTypeHandlerMap<JsonSerializer<?>> serializers;
@@ -79,7 +79,6 @@ public final class GsonBuilder {
   public GsonBuilder() {
     // setup default values
     ignoreVersionsAfter = VersionConstants.IGNORE_VERSIONS;
-    serializeLongAsString = false;
     serializeInnerClasses = true;
     prettyPrinting = false;
     escapeHtmlChars = true;
@@ -87,6 +86,7 @@ public final class GsonBuilder {
     innerClassExclusionStrategy = new InnerClassExclusionStrategy();
     modifierBasedExclusionStrategy = Gson.DEFAULT_MODIFIER_BASED_EXCLUSION_STRATEGY;
     excludeFieldsWithoutExposeAnnotation = false;
+    longSerializationPolicy = LongSerializationPolicy.DEFAULT;
     fieldNamingPolicy = Gson.DEFAULT_NAMING_POLICY;
     instanceCreators = new ParameterizedTypeHandlerMap<InstanceCreator<?>>();
     serializers = new ParameterizedTypeHandlerMap<JsonSerializer<?>>();
@@ -149,19 +149,6 @@ public final class GsonBuilder {
     return this;
   }
 
-  /**
-   * Configures Gson to output fields of type {@code long} as {@code String}s instead of a number.
-   *
-   * @param value the boolean value on whether or not {@code Gson} should serialize a {@code long}
-   * field as a {@code String}
-   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
-   * @since 1.3
-   */
-  public GsonBuilder serializeLongFieldsAsString(boolean value) {
-    serializeLongAsString = value;
-    return this;
-  }
-
   /**
    * Configures Gson to exclude inner classes during serialization.
    *
@@ -173,6 +160,19 @@ public final class GsonBuilder {
     return this;
   }
 
+  /**
+   * Configures Gson to apply a specific serialization policy for {@code Long} and {@code long}
+   * objects.
+   *
+   * @param serializationPolicy the particular policy to use for serializing longs.
+   * @return a reference to this {@code GsonBuilder} object to fulfill the "Builder" pattern
+   * @since 1.3
+   */
+  public GsonBuilder setLongSerializationPolicy(LongSerializationPolicy serializationPolicy) {
+    this.longSerializationPolicy = serializationPolicy;
+    return this;
+  }
+
   /**
    * Configures Gson to apply a specific naming policy to an object's field during serialization
    * and deserialization.
@@ -409,7 +409,7 @@ public final class GsonBuilder {
         customDeserializers);
 
     customSerializers.registerIfAbsent(DefaultTypeAdapters.getDefaultSerializers(
-        serializeSpecialFloatingPointValues, serializeLongAsString));
+        serializeSpecialFloatingPointValues, longSerializationPolicy));
 
     customDeserializers.registerIfAbsent(DefaultTypeAdapters.getDefaultDeserializers());
 

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

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2009 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;
+
+/**
+ * Defines the expected format for a {@code long} or {@code Long} type when its serialized.
+ *
+ * @since 1.3
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public enum LongSerializationPolicy {
+  /**
+   * This is the "default" serialization policy that will output a {@code long} object as a JSON
+   * number.  For example, assume an object has a long field named "f" then the serialized output
+   * would be:
+   * {@code {"f":123}}.
+   */
+  DEFAULT(new DefaultStrategy()),
+  
+  /**
+   * Serializes a long value as a quoted string.  For example, assume an object has a long field 
+   * named "f" then the serialized output would be:
+   * {@code {"f":"123"}}.
+   */
+  STRING(new StringStrategy());
+  
+  private final Strategy strategy;
+  
+  private LongSerializationPolicy(Strategy strategy) {
+    this.strategy = strategy;
+  }
+
+  /**
+   * Serialize this {@code value} using this serialization policy.
+   *
+   * @param value the long value to be serialized into a {@link JsonElement}
+   * @return the serialized version of {@code value}
+   */
+  public JsonElement serialize(Long value) {
+    return strategy.serialize(value);
+  }
+  
+  private interface Strategy {
+    JsonElement serialize(Long value);
+  }
+  
+  private static class DefaultStrategy implements Strategy {
+    public JsonElement serialize(Long value) {
+      return new JsonPrimitive(value);
+    }
+  }
+  
+  private static class StringStrategy implements Strategy {
+    public JsonElement serialize(Long value) {
+      return new JsonPrimitive(String.valueOf(value));
+    }
+  }
+}

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

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2009 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;
+
+import junit.framework.TestCase;
+
+/**
+ * Unit test for the {@link LongSerializationPolicy} class.
+ *
+ * @author Inderjeet Singh
+ * @author Joel Leitch
+ */
+public class LongSerializationPolicyTest extends TestCase {
+
+  public void testDefaultLongSerialization() throws Exception {
+    JsonElement element = LongSerializationPolicy.DEFAULT.serialize(1556L);
+    assertTrue(element.isJsonPrimitive());
+    
+    JsonPrimitive jsonPrimitive = element.getAsJsonPrimitive();
+    assertFalse(jsonPrimitive.isString());
+    assertTrue(jsonPrimitive.isNumber());
+    assertEquals(1556L, element.getAsLong());
+  }
+  
+  public void testStringLongSerialization() throws Exception {
+    JsonElement element = LongSerializationPolicy.STRING.serialize(1556L);
+    assertTrue(element.isJsonPrimitive());
+    
+    JsonPrimitive jsonPrimitive = element.getAsJsonPrimitive();
+    assertFalse(jsonPrimitive.isNumber());
+    assertTrue(jsonPrimitive.isString());
+    assertEquals("1556", element.getAsString());
+  }
+}

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

@@ -24,6 +24,7 @@ import junit.framework.TestCase;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
+import com.google.gson.LongSerializationPolicy;
 import com.google.gson.common.TestTypes.CrazyLongTypeAdapter;
 
 /**
@@ -530,7 +531,7 @@ public class PrimitiveTest extends TestCase {
   }  
   
   public void testLongAsStringSerialization() throws Exception {
-    gson = new GsonBuilder().serializeLongFieldsAsString(true).create();
+    gson = new GsonBuilder().setLongSerializationPolicy(LongSerializationPolicy.STRING).create();
     String result = gson.toJson(15L);
     assertEquals("\"15\"", result);
     
@@ -543,7 +544,7 @@ public class PrimitiveTest extends TestCase {
     long value = gson.fromJson("\"15\"", long.class);
     assertEquals(15, value);
 
-    gson = new GsonBuilder().serializeLongFieldsAsString(true).create();
+    gson = new GsonBuilder().setLongSerializationPolicy(LongSerializationPolicy.STRING).create();
     value = gson.fromJson("\"25\"", long.class);
     assertEquals(25, value);
   }