network.java

来自「自己写的轮询提问的小程序 新手刚学 多多指教 合乎哈」· Java 代码 · 共 102 行

/*
This is the network class of the PollServer. It handles all the network stuff
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 SharedClasses;

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

public class Network {
    public final static int BUFFER_SIZE = 4096*4;
    private InputStream in;
    private OutputStream out;
    private Socket clntSock;
    public final static byte CLIENT_DISCONNECTED = 10;
    public final static byte CHECK_BYTE = 0;
    public final static byte SERVER_SENDING_QUESTION = 1;
    public final static byte CLIENT_SENDING_ANSWER = 100;
    public final static byte QUESTION_CLOSED = 11;
        
    public Network(Socket c) {
        clntSock = c;
        try {
            in = clntSock.getInputStream();
            out = clntSock.getOutputStream();
        }
        catch (IOException e) { System.out.println("Client disconnected prematurely"); }
    }
    
    public boolean askQuestion(Question q) {
        if (q == null) return false;
        
        byte[] buf = q.getBytes();
        
        try {
            out.write(SERVER_SENDING_QUESTION);
            out.write(buf);
        }
        catch (IOException e) { return false; }
        
        return true;
    }

    public boolean closeQuestion() {
        try {
            out.write(QUESTION_CLOSED);
        }
        catch (IOException e) { return false; }
        
        return true;
    }
    
    public int checkForAnswer() {
        byte[] b = new byte[1];
        
        try {
            if (in.read(b) > 0) return (int) b[0];
        }
        catch (IOException e) { return -1; }
        
        return -1;
    }
    
    public boolean ping() {
        byte[] b = new byte[1];
        b[0] = CHECK_BYTE;
        
        try {
            out.write(b);
            
            if (in.read(b) > 0)
                return true;
        }
        catch (IOException e) { return false; }
        
        return false;        
    }
    
    public void close() {
        try {
            clntSock.close();
        }
        catch (IOException e) { }
    }
    

}