001/*
002 * Copyright (C) 2012 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.base;
018
019import com.google.common.annotations.GwtCompatible;
020import com.google.gwt.user.client.rpc.SerializationStreamReader;
021import com.google.gwt.user.client.rpc.SerializationStreamWriter;
022
023/**
024 * Custom GWT serializer for {@link Absent}.
025 *
026 * <p>GWT can serialize an absent {@code Optional} on its own, but the resulting object is a
027 * different instance than the singleton {@code Absent.INSTANCE}, which breaks equality. We
028 * implement a custom serializer to maintain the singleton property.
029 *
030 * @author Chris Povirk
031 */
032@GwtCompatible
033public class Absent_CustomFieldSerializer {
034  public static void deserialize(SerializationStreamReader reader, Absent<?> instance) {}
035
036  public static Absent<?> instantiate(SerializationStreamReader reader) {
037    return Absent.INSTANCE;
038  }
039
040  public static void serialize(SerializationStreamWriter writer, Absent<?> instance) {}
041}