80 lines
2.8 KiB
Java
80 lines
2.8 KiB
Java
/*
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* Copyright 2011 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.bytes;
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import io.netty.buffer.ChannelBuffer;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelPipeline;
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import io.netty.channel.MessageEvent;
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import io.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
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import io.netty.handler.codec.frame.LengthFieldPrepender;
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import io.netty.handler.codec.oneone.OneToOneDecoder;
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/**
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* Decodes a received {@link ChannelBuffer} into an array of bytes.
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* A typical setup for TCP/IP would be:
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* <pre>
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* {@link ChannelPipeline} pipeline = ...;
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*
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* // Decoders
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* pipeline.addLast("frameDecoder",
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* new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4));
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* pipeline.addLast("bytesDecoder",
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* new {@link ByteArrayDecoder}());
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*
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* // Encoder
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* pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4));
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* pipeline.addLast("bytesEncoder", new {@link ByteArrayEncoder}());
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* </pre>
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* and then you can use an array of bytes instead of a {@link ChannelBuffer}
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* as a message:
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* <pre>
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* void messageReceived({@link ChannelHandlerContext} ctx, {@link MessageEvent} e) {
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* byte[] bytes = (byte[]) e.getMessage();
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* ...
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* }
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* </pre>
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*/
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public class ByteArrayDecoder extends OneToOneDecoder {
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@Override
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protected Object decode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
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if (!(msg instanceof ChannelBuffer)) {
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return msg;
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}
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ChannelBuffer buf = (ChannelBuffer) msg;
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byte[] array;
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if (buf.hasArray()) {
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if (buf.arrayOffset() == 0 && buf.readableBytes() == buf.capacity()) {
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// we have no offset and the length is the same as the capacity. Its safe to reuse the array without copy it first
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array = buf.array();
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} else {
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// copy the ChannelBuffer to a byte array
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array = new byte[buf.readableBytes()];
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buf.getBytes(0, array);
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}
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} else {
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// copy the ChannelBuffer to a byte array
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array = new byte[buf.readableBytes()];
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buf.getBytes(0, array);
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}
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return array;
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}
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}
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