1/*
2 * Copyright (C) 2012 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.base;
18
19import com.google.common.annotations.GwtCompatible;
20import com.google.gwt.user.client.rpc.SerializationStreamReader;
21import com.google.gwt.user.client.rpc.SerializationStreamWriter;
22
23/**
24 * Custom GWT serializer for {@link Absent}.
25 *
26 * <p>GWT can serialize an absent {@code Optional} on its own, but the resulting object is a
27 * different instance than the singleton {@code Absent.INSTANCE}, which breaks equality. We
28 * implement a custom serializer to maintain the singleton property.
29 *
30 * @author Chris Povirk
31 */
32@GwtCompatible
33public class Absent_CustomFieldSerializer {
34  public static void deserialize(SerializationStreamReader reader, Absent<?> instance) {}
35
36  public static Absent<?> instantiate(SerializationStreamReader reader) {
37    return Absent.INSTANCE;
38  }
39
40  public static void serialize(SerializationStreamWriter writer, Absent<?> instance) {}
41}
42