Package org.jboss.netty.example.factorial

Source Code of org.jboss.netty.example.factorial.BigIntegerDecoder

/*
* Copyright 2009 Red Hat, Inc.
*
* Red Hat 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.jboss.netty.example.factorial;

import java.math.BigInteger;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.CorruptedFrameException;
import org.jboss.netty.handler.codec.frame.FrameDecoder;

/**
* Decodes the binary representation of a {@link BigInteger} prepended
* with a magic number ('F' or 0x46) and a 32-bit integer length prefix into a
* {@link BigInteger} instance.  For example, { 'F', 0, 0, 0, 1, 42 } will be
* decoded into new BigInteger("42").
*
* @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
*
* @version $Rev: 2125 $, $Date: 2010-02-02 12:13:15 +0900 (Tue, 02 Feb 2010) $
*/
public class BigIntegerDecoder extends FrameDecoder {

    @Override
    protected Object decode(
            ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
        // Wait until the length prefix is available.
        if (buffer.readableBytes() < 5) {
            return null;
        }

        buffer.markReaderIndex();

        // Check the magic number.
        int magicNumber = buffer.readUnsignedByte();
        if (magicNumber != 'F') {
            buffer.resetReaderIndex();
            throw new CorruptedFrameException(
                    "Invalid magic number: " + magicNumber);
        }

        // Wait until the whole data is available.
        int dataLength = buffer.readInt();
        if (buffer.readableBytes() < dataLength) {
            buffer.resetReaderIndex();
            return null;
        }

        // Convert the received data into a new BigInteger.
        byte[] decoded = new byte[dataLength];
        buffer.readBytes(decoded);

        return new BigInteger(decoded);
    }
}
TOP

Related Classes of org.jboss.netty.example.factorial.BigIntegerDecoder

TOP
Copyright © 2018 www.massapi.com. All rights reserved.
All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.