/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
/**
* Project : MapleFetion2
* Package : net.solosky.net.maplefetion.net.tcp
* File : TcpTransfer.java
* Author : solosky < solosky772@qq.com >
* Created : 2010-1-6
* License : Apache License 2.0
*/
package net.solosky.maplefetion.net.tcp;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import net.solosky.maplefetion.net.AbstractTransfer;
import net.solosky.maplefetion.net.Port;
import net.solosky.maplefetion.net.TransferException;
import org.apache.log4j.Logger;
/**
*
* TCP方式消息传输
*
* @author solosky <solosky772@qq.com>
*/
public class TcpTransfer extends AbstractTransfer
{
/**
* 内部线程，用于读取数据
*/
private Thread readThread;
/**
* SOCKET
*/
private Socket socket;
/**
* 读取对象
*/
private InputStream reader;
/**
* 发送对象
*/
private OutputStream writer;
/**
* 日志记录
*/
private static Logger logger = Logger.getLogger(TcpTransfer.class);
/**
* 关闭标志
*/
private volatile boolean userCloseFlag;
/**
* 构造函数
*
*/
public TcpTransfer(Port port) throws TransferException
{
try {
socket = new Socket();
logger.debug("Connecting to "+port.toString()+"....");
socket.connect(new InetSocketAddress(port.getAddress(), port.getPort()));
logger.debug("Connected to "+port.toString()+".");
reader = socket.getInputStream();
writer = socket.getOutputStream();
} catch (IOException e) {
logger.warn("Cannot connect to "+port.toString()+"!!!!");
throw new TransferException(e);
}
userCloseFlag = false;
}
@Override
public void startTransfer() throws TransferException
{
Runnable readRunner = new Runnable()
{
public void run()
{
try {
logger.debug("Socket ready for read.. "+ socket);
logger.debug("Local port:"+socket.getLocalSocketAddress().toString());
//初始化缓冲区和一些变量
byte[] buff = new byte[1024];
int len = 0;
//循环读取数据，直到遇到流的末尾，或者用户主动关闭连接
//注意这里不能在stopTransfer里只改变关闭标志而不关闭流，否则会在reader.read()方法阻塞掉，即是中断线程也没用
//线程在阻塞读取数据时是不能中断的，只能强制关闭流，阻塞的reader.read()方法就会立即抛出IO异常，就可以结束读线程
while(true) {
len = reader.read(buff, 0, buff.length);
//这里还需要判断是否读取到流的末尾，否则会进入死循环，通常返回-1表示流的结尾
//如果读取到结尾，表明是服务器主动关闭了连接，抛出这个异常，通知上层做资源清理工作
if(len==-1) {
logger.debug("Connection closed by server.."+socket);
raiseException(new TransferException("Connection closed by server. "+socket));
break;
}else {
bytesRecived(buff, 0, len);
}
}
} catch (IOException e) {
//当发生IO异常时可能是网络出现问题，也可能是用户关闭了连接，这里需要判断下
if(!userCloseFlag) {
logger.warn("Connection error.. "+socket);
raiseException(new TransferException(e));
}else {
logger.debug("Connection closed by user.."+socket);
}
}
//程序执行到这里，表明流已经读取完毕，可能是服务器主动关闭了连接，或者用户关闭了连接
//如果是服务器关闭了连接，这里就需要关闭流，如果是用户关闭了流，就什么也不做，因为在stopTranfer方法中就已经关闭了
if(!userCloseFlag) {
userCloseFlag = true;
try {
writer.close();
reader.close();
} catch (IOException e) {
logger.warn("Close socket stream failed.. "+socket, e);
}
}
}
};
readThread = new Thread(readRunner);
readThread.setName(getTransferName());
readThread.start();
}
@Override
public void stopTransfer() throws TransferException
{
//这里设置一个关闭标志，并关闭流，读线程就会抛出IO异常，然后判断关闭标志结束线程
if(!this.userCloseFlag) {
this.userCloseFlag = true;
try {
this.writer.close();
this.reader.close();
} catch (IOException e) {
logger.warn("Close socket stream failed.."+socket , e);
}
}
}
@Override
public String getTransferName()
{
return "TCPTransfer-" + socket;
}
/**
* @return the socket
*/
public Socket getSocket()
{
return socket;
}
/* (non-Javadoc)
* @see net.solosky.maplefetion.net.AbstractTransfer#sendBytes(byte[], int, int)
*/
@Override
protected void sendBytes(byte[] buff, int offset, int len)
throws TransferException
{
try {
this.writer.write(buff, offset, len);
this.writer.flush();
} catch (IOException e) {
throw new TransferException(e);
}
}
}