/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.marshalling;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;

import org.jboss.marshalling.Marshaller;

MessageToByteEncoder implementation which uses JBoss Marshalling to marshal an Object. Be aware that this encoder is not compatible with an other client that just use JBoss Marshalling as it includes the size of every Object that gets serialized in front of the Object itself. Use this with MarshallingDecoder See JBoss Marshalling website
for more information
/**
 * {@link MessageToByteEncoder} implementation which uses JBoss Marshalling to marshal
 * an Object. Be aware that this encoder is not compatible with an other client that just use
 * JBoss Marshalling as it includes the size of every {@link Object} that gets serialized in
 * front of the {@link Object} itself.
 *
 * Use this with {@link MarshallingDecoder}
 *
 * See <a href="http://www.jboss.org/jbossmarshalling">JBoss Marshalling website</a>
 * for more information
 *
 */
@Sharable
public class MarshallingEncoder extends MessageToByteEncoder<Object> {

    private static final byte[] LENGTH_PLACEHOLDER = new byte[4];
    private final MarshallerProvider provider;

    
Creates a new encoder.
Params:
provider – the MarshallerProvider to use/**
     * Creates a new encoder.
     *
     * @param provider the {@link MarshallerProvider} to use
     */
    public MarshallingEncoder(MarshallerProvider provider) {
        this.provider = provider;
    }

    @Override
    protected void encode(ChannelHandlerContext ctx, Object msg, ByteBuf out) throws Exception {
        Marshaller marshaller = provider.getMarshaller(ctx);
        int lengthPos = out.writerIndex();
        out.writeBytes(LENGTH_PLACEHOLDER);
        ChannelBufferByteOutput output = new ChannelBufferByteOutput(out);
        marshaller.start(output);
        marshaller.writeObject(msg);
        marshaller.finish();
        marshaller.close();

        out.setInt(lengthPos, out.writerIndex() - lengthPos - 4);
    }
}