textlinedecoder.java

利用mina框架写的一个通信实例。初学者的一个好教程。

/*
 *   @(#) $Id: TextLineDecoder.java 357871 2005-12-20 01:56:40Z trustin $
 *
 *   Copyright 2004 The Apache Software Foundation
 *
 *   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.apache.mina.examples.reverser;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.protocol.ProtocolDecoder;
import org.apache.mina.protocol.ProtocolDecoderOutput;
import org.apache.mina.protocol.ProtocolSession;
import org.apache.mina.protocol.ProtocolViolationException;

/**
 * Decodes a text line into a string.
 * 
 * @author The Apache Directory Project ([e-mail])
 * @version $Rev: 357871 $, $Date: 2005-12-20 10:56:40 +0900 (Tue, 20 Dec 2005) $,
 */
public class TextLineDecoder implements ProtocolDecoder {

	private StringBuffer decodeBuf = new StringBuffer();

	public void decode(ProtocolSession session, ByteBuffer in,
			ProtocolDecoderOutput out) throws ProtocolViolationException {

		System.out.println("--info session:" + session.getCreationTime());

		do {
			byte b = in.get();
			switch (b) {
			case '\r':
				break;
			case '\n':
				String result = decodeBuf.toString();
				decodeBuf.delete(0, decodeBuf.length());
				out.write(result);
				break;
			default:
				decodeBuf.append((char) b);
			}

			// Don't accept too long line
			if (decodeBuf.length() > 256) {
				decodeBuf.delete(0, decodeBuf.length());
				throw new ProtocolViolationException("The line is too long.");
			}
		} while (in.hasRemaining());

		// throw new ProtocolViolationException("zhaohongju");
	}
}