import java.awt.*;
import java.awt.event.*;
/** (C) 2000 Charles Consulting, LLC <br>
Button which repeats action if held down. Note that
this class will start a daemon Thread when pressed. The 
thread is normally waiting. It will terminate up to
'detachCheck' milliseconds after Button is removed from its 
parent. <br>
The ActionEvent sent will contain, as a string, the number
of cycles the button has been held down for. */

public class HolddownButton extends Button {

	/** millisecond delay between processing */
	public static final int buttonDelay = 500;

	/** how to to wait between checks to see if button was detached */
	public static final int detachCheck = 600000; //ten minutes

	/** current state of button */
	private boolean isDown;

	/** thread to process multiple events if button held down */
	private TimerThread thread;

	/** constructor */
	public HolddownButton( )
	{
		super( );
		addMouseListener( new MouseAdapter( ) {
			public void mousePressed(MouseEvent e)
			{ setDown(true); }

			public void mouseReleased(MouseEvent e)
			{ setDown(false); } 

			public void mouseExited(MouseEvent e)
			{ setDown(false); } 
		});
	}

	private final synchronized void setDown(boolean d)
	{
		isDown = d;
		if (isDown)
			{
			if (thread == null)
				{
				thread = new TimerThread();
				thread.setDaemon(true);
				thread.start( );
				}
			else
				notify( );
			}
	}

	/** allow inner class to access protected method */
	private final void forwardEvent(AWTEvent e)
	{
		super.processEvent(e);
	}

	private class TimerThread extends Thread {
	
		/** threaded function. Sends event while button
		held down; exits when button removed from parent */
		public void run( )
		{
			while (getParent( ) != null)
				{
				try {
					sleep(buttonDelay);
					}
				catch (InterruptedException e) { continue;}
				synchronized(HolddownButton.this) {
					while (!isDown && getParent( ) != null)
						try {
							HolddownButton.this.wait(detachCheck);
							}
						catch (InterruptedException e) 
							{ continue; }
					}
				ActionEvent ev = 
					new ActionEvent(HolddownButton.this,
						ActionEvent.ACTION_PERFORMED,"");
				forwardEvent(ev);
				}
			thread = null;
		}
		
	}
}