org.rzo.netty.ahessian.serialization.HessianDecoder.java Source code

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Here is the source code for org.rzo.netty.ahessian.serialization.HessianDecoder.java

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/*******************************************************************************
 * Copyright  2015 rzorzorzo@users.sf.net
 *
 * 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 org.rzo.netty.ahessian.serialization;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;

import java.io.IOException;
import java.io.InputStream;

import org.rzo.netty.ahessian.Constants;
import org.rzo.netty.ahessian.io.InputStreamConsumer;
import org.rzo.netty.ahessian.io.PullInputStreamConsumer;

import com.caucho.hessian4.io.HessianInput;

/**
 * Decodes a {@link ChannelBuffer} into a {@link java.lang.Object}. A typical
 * setup for a serialization protocol in a TCP/IP socket would be:
 * 
 * <pre>
 * {@link ChannelPipeline} pipeline = ...;
 * 
 * // Encoder
 * pipeline.addLast("outputStream", new {@link io.OutputStream}());
 * pipeline.addLast("hessianEncoder", new {@link HessianEncoder}());
 * 
 * // Decoder
 * pipeline.addLast("inputStream", new {@link io.InputStream}());
 * pipeline.addLast("hessianDecoder", new {@link HessianDecoder}());
 * pipeline.addLast("handler", new MyHandler());
 * </pre>
 * 
 * and then, within the handler you can use a {@link java.lang.Object} instead
 * of a {@link ChannelBuffer} as a message:
 * 
 * <pre>
 * void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
 * {
 *    // get the message
 *    Object msg = e.getMessage();
 *    // return the current time
 *    ch.write(new Date());
 * }
 * </pre>
 */

public class HessianDecoder extends PullInputStreamConsumer {

    public HessianDecoder() {
        super(new InputStreamConsumer() {
            InputStream _in;

            @Override
            public void consume(ChannelHandlerContext ctx, InputStream in) {
                _in = in;
                try {
                    HessianInput hin = new HessianInput(_in);
                    while (true) {
                        Object obj = hin.readObject(null);
                        if (obj != null)
                            ctx.fireChannelRead(obj);
                    }
                } catch (Exception ex) {
                    if (ex.getMessage().startsWith("H expected got 0x0 ("))
                        Constants.ahessianLogger.info("Ping received");
                    else
                        Constants.ahessianLogger.debug("", ex);
                }
            }

            @Override
            public boolean isBufferEmpty() {
                if (_in == null)
                    return true;
                try {
                    return _in.available() == 0;
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return true;
            }

            @Override
            public void setContext(ChannelHandlerContext ctx) {
                // TODO Auto-generated method stub

            }

        });
        // TODO Auto-generated constructor stub
    }

}