// StatusThreads - displays the Threads status of the Java virtual machine
//
// Partly based on the ThreadLister example fro "Java in a Nutshell".
// See http://www.ora.com/www/catalog/books/javanut/examples/
//
// Copyright (C) 1996 by Jef Poskanzer <jef@mail.acme.com>.  All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.

import java.applet.*;
import java.awt.*;
import java.io.*;

public class StatusThreads extends Applet implements Runnable
    {

    // Applet info.
    public String getAppletInfo()
	{
	return getClass().getName() +
" - Copyright (C) 1996 by Jef Poskanzer <jef@mail.acme.com>.  All rights reserved.";
	}

    TextArea textArea;

    // Called when the applet is first created.
    public void init()
	{
	Acme.GuiUtils.handleBgcolor( this );

//	// Figure out how big the TextArea should be, by trial&error.
//	// A binary search would be faster though.
//	int rows = 1;
//	int cols = 1;
//	Dimension pd;
//	do
//	    {
//	    textArea = new TextArea( rows + 1, cols );
//	    pd = textArea.preferredSize();
//	    }
//	while ( pd.width <= d.width );
//	do
//	    {
//	    textArea = new TextArea( rows, cols + 1 );
//	    pd = textArea.preferredSize();
//	    }
//	while ( pd.height <= d.height );
//	textArea = new TextArea( rows, cols );

	setLayout( new BorderLayout() );
	textArea = new TextArea();
	textArea.setEditable( false );
	add( "Center", textArea );
	validate();
	}

    Thread thread = null;
    Runtime runtime = Runtime.getRuntime();

    // Called when the applet should start itself.
    public void start()
	{
        if ( thread == null )
            {
            // Start the thread.
            thread = new Thread(this);
            thread.start();
            }
	}

    // Called when the applet should stop itself.
    public void stop()
	{
        if ( thread != null )
            {
	    // Stop the thread.
            thread.stop();
            thread = null;
            }
	}

    // This is the part of Runnable that we implement - the routine that
    // gets called when the thread is started.
    public void run()
	{
        Thread me = Thread.currentThread();
        me.setPriority( Thread.MIN_PRIORITY );
	while ( thread == me )
	    {
	    Acme.TextcompOutputStream t =
		new Acme.TextcompOutputStream( textArea );
	    Acme.APrintStream p = new Acme.APrintStream( t );
	    listAll( p );
	    repaint();
	    try
		{
		Thread.sleep( 10000 );	// ten seconds
		}
	    catch ( InterruptedException e ) {}
	    }
	}

    static void listThread( PrintStream out, Thread t, String indent )
	{
        if ( t == null )
	    return;
        out.println(
	    indent + "Thread: " + t.getName() +
	    "  Priority: " + t.getPriority() +
	    ( t.isDaemon() ? " Daemon" : "" ) +
	    ( t.isAlive() ? "" : " Inactive" ) );
	}

    static void listGroup( PrintStream out, ThreadGroup g, String indent )
	{
        if ( g == null )
	    return;

        out.println(
	    indent + "Thread Group: " + g.getName() +
	    "  Max Priority: " + g.getMaxPriority() +
	    ( g.isDaemon() ? " Daemon" : "" ) );

	String extraIndent = "    ";

        int numThreadsEst = g.activeCount();
        Thread[] threads = new Thread[numThreadsEst * 2];
        int numThreads = g.enumerate( threads, false );
        for ( int i = 0; i < numThreads; ++i )
            listThread( out, threads[i], extraIndent + indent );

        int numGroupsEst = g.activeGroupCount();
        ThreadGroup[] groups = new ThreadGroup[numGroupsEst * 2];
        int numGroups = g.enumerate( groups, false );
        for ( int i = 0; i < numGroups; ++i )
            listGroup( out, groups[i], extraIndent + indent );
	}

    static void listAll( PrintStream out )
	{
        ThreadGroup currentThreadGroup;
        ThreadGroup rootThreadGroup;
        ThreadGroup parent;

        // Start with the current thread group.
        currentThreadGroup = Thread.currentThread().getThreadGroup();

        // Now follow the tree to the root thread group.
        rootThreadGroup = currentThreadGroup;
        parent = rootThreadGroup.getParent();
        while ( parent != null )
	    {
            rootThreadGroup = parent;
            parent = parent.getParent();
	    }

        // And list it, recursively.
        listGroup( out, rootThreadGroup, "" );
	}

    // Main program, so we can run as an application too.
    public static void main( String[] args )
	{
	new Acme.MainFrame( new StatusThreads(), args, 400, 500 );
	}

    }