package gnu.dtools.ritopt;
/**
* StreamPrinter.java
*
* Version:
* $Id: StreamPrinter.java 2209 2007-08-01 18:23:38Z coezbek $
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
/**
* Reads data from an input stream and outputs to a print stream. This class
* is used by the OptionMenu class to read from both standard output and
* standard error simultaneously when a shell command is executed. Since the
* StreamPrinter processes streams on a separate thread, deadlock is
* prevented.<p>
*
* <hr>
*
* <pre>
* Copyright (C) Damian Ryan Eads, 2001. All Rights Reserved.
*
* ritopt 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.
* ritopt 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 ritopt; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* </pre>
*
* @author Damian Eads
*/
public class StreamPrinter implements Runnable, Stoppable {
/**
* The input stream to read from.
*/
private InputStream stream;
/**
* The print stream to redirect to.
*/
private PrintStream out;
/**
* The object to stop.
*/
private Stoppable stop;
/**
* Whether this StreamPrinter has stopped processing.
*/
private boolean stopped;
/**
* Whether the buffer should be flushed.
*/
private boolean flush;
/**
* The thread associated with this StreamPrinter.
*/
private Thread thread;
/**
* Constructs a new StreamPrinter.
*
* @param s The stream to read from.
* @param p The stream to output to.
*/
public StreamPrinter( InputStream s, PrintStream p ) {
stream = s;
out = p;
thread = new Thread( this );
}
/**
* Starts the thread associated with this StreamPrinter.
*/
public void start() throws InterruptedException {
thread.start();
}
/**
* Sets the object to stop when this object is finished.
*
* @param tostop The object to stop.
*/
public void setStop( Stoppable tostop ) {
synchronized( this ) {
stop = tostop;
}
}
/**
* Returns whether this StreamPrinter has stopped processing.
*
* @returns A boolean value.
*/
public boolean isStopped() {
return stopped;
}
/**
* Sets whether the output stream should be flushed after each output
* step.
*
* @param b A boolean value.
*/
public void setFlush( boolean flush ) {
synchronized ( this ) {
this.flush = flush;
}
}
/**
* Stops this StreamPrinter's processing.
*/
public void stop() {
synchronized( this ) {
stopped = true;
}
if ( stop != null ) {
synchronized( stop ) {
if ( !stop.isStopped() ) {
stop.stop();
}
}
}
}
/**
* Joins this StreamPrinter's thread with the other threads.
*/
public void join() throws InterruptedException {
thread.join();
}
/**
* Start the StreamPrinter thread. This is done automatically during
* construction.
*/
// This implementation is lousy; buffering is needed.
public void run() {
int buf;
try {
boolean me;
while ( !stopped && ( buf = stream.read() ) != -1 ) {
synchronized( this ) {
me = flush;
}
synchronized( out ) {
out.print( (char)buf );
if ( me ) out.flush();
}
}
}
catch ( IOException e ) {
out.println( "I/O error" );
}
finally {
synchronized( out ) {
out.flush();
}
stop();
}
}
}