TextAreaOutputStream.java

/*	
	Copyright 2012 Jan Ove Saltvedt
	
	This file is part of KBot.

    KBot 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 3 of the License, or
    (at your option) any later version.

    KBot 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 KBot.  If not, see <http://www.gnu.org/licenses/>.
	
*/

package com.kbotpro.various;

import java.io.*;
import java.util.*;
import javax.swing.*;

public class TextAreaOutputStream
extends OutputStream
{

// *****************************************************************************
// INSTANCE PROPERTIES
// *****************************************************************************

private JTextArea                       textArea;                               // target text area
private int                             maxLines;                               // maximum lines allowed in text area
private LinkedList                      lineLengths;                            // length of lines within text area
private int                             curLength;                              // length of current line
private byte[]                          oneByte;                                // array for write(int val);

// *****************************************************************************
// INSTANCE CONSTRUCTORS/INIT/CLOSE/FINALIZE
// *****************************************************************************

public TextAreaOutputStream(JTextArea ta) {
    this(ta,1000);
    }

public TextAreaOutputStream(JTextArea ta, int ml) {
    if(ml<1) { throw new IllegalArgumentException("Maximum lines of "+ml+" in TextAreaOutputStream constructor is not permitted"); }
    textArea=ta;
    maxLines=ml;
    lineLengths=new LinkedList();
    curLength=0;
    oneByte=new byte[1];
    }

// *****************************************************************************
// INSTANCE METHODS - ACCESSORS
// *****************************************************************************

public synchronized void clear() {
    lineLengths=new LinkedList();
    curLength=0;
    textArea.setText("");
    }

/** Get the number of lines this TextArea will hold. */
public synchronized int getMaximumLines() { return maxLines; }

/** Set the number of lines this TextArea will hold. */
public synchronized void setMaximumLines(int val) { maxLines=val; }

// *****************************************************************************
// INSTANCE METHODS
// *****************************************************************************

public void close() {
    if(textArea!=null) {
        textArea=null;
        lineLengths=null;
        oneByte=null;
        }
    }

public void flush() {
    }

public void write(int val) {
    oneByte[0]=(byte)val;
    write(oneByte,0,1);
    }

public void write(byte[] ba) {
    write(ba,0,ba.length);
    }

public synchronized void write(byte[] ba,int str,int len) {
    try {
        curLength+=len;
        if(bytesEndWith(ba,str,len,LINE_SEP)) {
            lineLengths.addLast(new Integer(curLength));
            curLength=0;
            if(lineLengths.size()>maxLines) {
                textArea.replaceRange(null,0,((Integer)lineLengths.removeFirst()).intValue());
                }
            }
        for(int xa=0; xa<10; xa++) {
            try { textArea.append(new String(ba,str,len)); break; }
            catch(Throwable thr) {                                                 // sometimes throws a java.lang.Error: Interrupted attempt to aquire write lock
                if(xa==9) { thr.printStackTrace(); }
                else      { Thread.sleep(200);    }
                }
            }
        }
    catch(Throwable thr) {
        CharArrayWriter caw=new CharArrayWriter();
        thr.printStackTrace(new PrintWriter(caw,true));
        textArea.append(System.getProperty("line.separator","\n"));
        textArea.append(caw.toString());
        }
    }

private boolean bytesEndWith(byte[] ba, int str, int len, byte[] ew) {
    if(len<LINE_SEP.length) { return false; }
    for(int xa=0,xb=(str+len-LINE_SEP.length); xa<LINE_SEP.length; xa++,xb++) {
        if(LINE_SEP[xa]!=ba[xb]) { return false; }
        }
    return true;
    }

// *****************************************************************************
// STATIC PROPERTIES
// *****************************************************************************

static private byte[]                   LINE_SEP=System.getProperty("line.separator","\n").getBytes();

} /* END PUBLIC CLASS */