talkthread.java

自己写的轮询提问的小程序 新手刚学 多多指教 合乎哈

/*
TalkThread is the thread class that talks to the clients (asks questions, etc).
Copyright (C) 2005-2006  Igor Partola, Michael J. Krikonis, Clark University

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

package PollServer;

import java.net.*;
import java.io.*;
import SharedClasses.*;

class TalkThread  implements Runnable {
        private Network myNet;
        private Thread t;
        private PollServerThread parent;
        private Question currentQuestion = null;
        private boolean endOfLife = false;
        private int status = 0;
        private static final int QUESTION_CLOSED = -2;
        
        private final static int BUFFER_SIZE = 4*4096;
       
        TalkThread(Socket c, PollServerThread p) {
            myNet = new Network(c);
            parent = p;
            parent.getParent().addTalkThread(this);
            
        }

        public void start() {
            t = new Thread(this);
            t.start();
        }
        
        private void waitForQuestion() {
            int pingCount = 0;
            try {
                while (true) {
                    t.sleep (50);
                    if (currentQuestion != null) {
                        myNet.askQuestion(currentQuestion);
                        currentQuestion = null;
                        return;
                    }
                    pingCount++;
                    if (pingCount > 15) {
                        if (!myNet.ping()) {
                            endOfLife = true;
                            return;
                        }
                        pingCount = 0;
                    }
                }
            }
            catch (InterruptedException e) {endOfLife = true;}
        }
        
        private int waitForAnswer(){
            int answer = -1;
            int tmp_answer = -1;
            int pingCount = 0;
            
            try {
                while (status != QUESTION_CLOSED) {
                        t.sleep (50);
                        tmp_answer = myNet.checkForAnswer();
                        if (tmp_answer >= 0) answer = tmp_answer;

                        pingCount++;
                        if (pingCount > 15) {
                            if (!myNet.ping()) {
                                endOfLife = true;
                                return answer;
                            }
                            pingCount = 0;
                        }                        
                }
            }
            catch (InterruptedException e) {endOfLife = true;}
            
            return answer;                
        }
        
        public void run() {
            int answer;

            
            while (true) {
                if (endOfLife) break;
                status = 0;
                currentQuestion = null;
                
                waitForQuestion();
                
                if (endOfLife) break;
                
                answer = waitForAnswer();
                
                if (!endOfLife) {
                    myNet.closeQuestion();
                    if (answer >= 0) parent.getParent().updateVotes(answer);
                    answer = -1;
                }
                else {
                    if (answer >= 0) parent.getParent().updateVotes(answer);
                    answer = -1;
                    break;
                }
            }
            
            stop();
        }
        
        public void setQuestion(Question q) {
            currentQuestion = q;
        }
         
        public void stop() {
            myNet.close();
            endOfLife = true;
            parent.getParent().removeTalkThread(this);
            t = null;
        }
        
        public void closeQuestion() {
            status = QUESTION_CLOSED;
        }
}