JGroups实现聊天小程序

package com.lei.jgoups;

import java.io.bufferedreader;

import java.io.datainputstream;

import java.io.dataoutputstream;

import java.io.inputstream;

import java.io.inputstreamreader;

import java.io.outputstream;

import java.util.linkedlist;

import java.util.list;

import org.jgroups.jchannel;

import org.jgroups.message;

import org.jgroups.receiveradapter;

import org.jgroups.view;

import org.jgroups.util.util;

public class simplechat extends receiveradapter{

  jchannel channel;

  string user_name=system.getproperty( "user.name" , "n/a" );

  final list<string> state= new linkedlist<string>();

  public static void main(string[] args) throws exception {

  new simplechat().start();

  }

  private void start() throws exception {

  channel= new jchannel(); // 使用默认的配置, udp.xml【ybxiang:】该文件位于jgroups-x.y.z.final.jar中。

  channel.setreceiver( this ); //注册一个 receiver 来接收消息并查看变化

  channel.connect( "chatcluster" );

  channel.getstate( null , 10000 );

  eventloop();

  channel.close();

  }

  private void eventloop() {

  bufferedreader in = new bufferedreader( new inputstreamreader(system.in));

  while ( true ) {

  try {

  system.out.print( ">" );

  system.out.flush();

  string line=in.readline().tolowercase();

  if (line.startswith( "quit" ) || line.startswith( "exit" ))

   break ;

  line= "[" + user_name + "] " + line;

  message msg= new message( null , line);

  channel.send(msg);

  }

  catch (exception e) {

  }

  }

  }

  //如果有节点加入后会回调此函数

  public void viewaccepted(view new_view) {

  system.out.println( "** view: " + new_view);

  }

  //接收到消息后会调用此函数

  public void receive(message msg) {

  string line=msg.getsrc() + ": " + msg.getobject();

  system.out.println(line);

  synchronized (state) { //同步调用

  state.add(line);

  }

  }

  //getstate回调方法

  public void getstate(outputstream output) throws exception {

  synchronized (state) {

  util.objecttostream(state, new dataoutputstream(output));

  }

  }

  // 从input stream中读取状态，然后做相应的设置：

  public void setstate(inputstream input) throws exception {

  list<string> list;

  list=(list<string>)util.objectfromstream( new datainputstream(input));

  synchronized (state) {

  state.clear();

  state.addall(list);

  }

  system.out.println(list.size() + " messages in chat history):" );

  for (string str: list) {

  system.out.println(str);

  }

  }

}