OutputHandler.java

/* 
** Author(s): Miguel Calejo
** Contact:   interprolog@declarativa.com, http://www.declarativa.com
** Copyright (C) Declarativa, Portugal, 2000-2002
** Use and distribution, without any warranties, under the terms of the 
** GNU Library General Public License, readable in http://www.fsf.org/copyleft/lgpl.html
*/
package com.declarativa.interprolog.util;
import java.io.*;
import java.util.*;
import com.declarativa.interprolog.*;

public class OutputHandler extends Thread {
        InputStream sourceStream;
        Vector listeners;
        private boolean ignoreStreamEnd;
        
        public OutputHandler(InputStream s){
                if (s instanceof BufferedInputStream) sourceStream = s;
                else sourceStream = new BufferedInputStream(s);
                listeners = new Vector();
                ignoreStreamEnd=false;
        }
        
        public synchronized void addOutputListener(OutputListener ol){
                listeners.addElement(ol);
        }
        public synchronized void removeOutputListener(OutputListener ol){
                listeners.removeElement(ol);
        }
        
        public boolean hasListener(OutputListener ol){
                return listeners.contains(ol);
        }
        
        public void run(){
                byte[] buffer = new byte[1024]; 
                while(true) {
                        try{
                                int nchars = sourceStream.read(buffer,0,buffer.length);
                                if (nchars==-1){
                                        fireStreamEnded();
                                        break;
                                } else fireABs(buffer,nchars);
                        } catch (IOException ex){ throw new IPException("Problem fetching output:"+ex);}
                }
        }
        synchronized void fireStreamEnded(){
                if (ignoreStreamEnd) return;
                for (int L=0; L<listeners.size(); L++)
                        ((OutputListener)(listeners.elementAt(L))).streamEnded();
        }
        synchronized void fireABs(byte[] buffer,int nbytes){
                for (int L=0; L<listeners.size(); L++)
                        ((OutputListener)(listeners.elementAt(L))).analyseBytes(buffer,nbytes);
        }
        
        public void setIgnoreStreamEnd(boolean ignore){
                ignoreStreamEnd=ignore;
        }
}

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