cassandra-trunk/src/java/org/apache/cassandra/net/NoPayload.java
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.cassandra.net;

import org.apache.cassandra.io.IVersionedSerializer;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;

/**
 * Empty message payload - primarily used for responses.
 *
 * Prefer this singleton to writing one-off specialised classes.
 */
public class NoPayload
{
    public static final NoPayload noPayload = new NoPayload();

    private NoPayload() {}

    public static final IVersionedSerializer<NoPayload> serializer = new IVersionedSerializer<NoPayload>()
    {
        public void serialize(NoPayload noPayload, DataOutputPlus out, int version)
        {
            if (noPayload != NoPayload.noPayload)
                throw new IllegalArgumentException();
        }

        public NoPayload deserialize(DataInputPlus in, int version)
        {
            return noPayload;
        }

        public long serializedSize(NoPayload noPayload, int version)
        {
            return 0;
        }
    };
}
