MonitorInputStream.java

/*
 * IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
 *
 * http://izpack.org/
 * http://izpack.codehaus.org/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.izforge.izpack.util;

import java.io.*;

/**
 * This is a grabber for stdout and stderr. It will be launched once at command execution end
 * terminates if the apropriate stream runs out of data.
 *
 * @author Olexij Tkatchenko <ot@parcs.de>
 */
public class MonitorInputStream implements Runnable
{

    private BufferedReader reader;

    private BufferedWriter writer;

    private boolean shouldStop = false;

    /**
     * Construct a new monitor.
     *
     * @param in  The input to read.
     * @param out The writer to write to.
     */
    public MonitorInputStream(Reader in, Writer out)
    {
        this.reader = new BufferedReader(in);
        this.writer = new BufferedWriter(out);
    }

    /**
     * Request stopping this thread.
     */
    public void doStop()
    {
        this.shouldStop = true;
    }

    /**
     * {@inheritDoc}
     */
    public void run()
    {
        try
        {
            String line;
            while ((line = this.reader.readLine()) != null)
            {
                this.writer.write(line);
                this.writer.newLine();
                this.writer.flush();
                if (this.shouldStop)
                {
                    return;
                }
            }
        }
        catch (IOException ioe)
        {
            ioe.printStackTrace(System.out);
        }
    }
}