busybox.java

java高级使用教程 全书一共分六章

// BusyBox - a busy-box
//
// Copyright (C)1996,1998 by Jef Poskanzer <[e-mail]>. 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.
//
// Visit the ACME Labs Java page for up-to-date versions of this and other
// fine Java utilities: http://www.acme.com/java/

package Acme.Widgets;

import java.awt.*;

/// A busy-box.
// <P>
// Puts up a dialog with a specified message.  All user input is locked
// out.  When the program is done with its task, it can unlock things by
// calling the done() method.
// <P>
// Sample usage:
// <IMG ALIGN=RIGHT WIDTH=151 HEIGHT=32 SRC="BusyBox.png">
// <BLOCKQUOTE><PRE><CODE>
// BusyBox b = new BusyBox( this, "Sample BusyBox" );
// b.show();
// [your task here]
// b.done();
// </CODE></PRE></BLOCKQUOTE>
// <P>
// NOTE: do not use this inside an event handler call!  With some browsers
// this will cause a deadlock.  Instead, have your event handler start a new
// thread to run the busy box and task.
// <P>
// <A HREF="/resources/classes/Acme/Widgets/BusyBox.java">Fetch the software.</A><BR>
// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>

public class BusyBox extends Dialog implements Runnable
    {

    /// Constructor, default title.
    public BusyBox( Frame parent, String message )
	{
	this( parent, "Busy", message );
	}

    /// Constructor, specified title.
    public BusyBox( Frame parent, String title, String message )
	{
	super( parent, title, true );

	setResizable( false );
	setBackground( Acme.GuiUtils.busyColor );

	GridBagLayout gb = new GridBagLayout();
	setLayout( gb );
	GridBagConstraints gbc = new GridBagConstraints();
	gbc.insets = new Insets( 5, 5, 5, 5 );

	ImageLabel imageLabel = new ImageLabel( Acme.GuiUtils.busyIcon( this ) );
	gb.setConstraints( imageLabel, gbc );
	add( imageLabel );
	Label label = new Label( message );
	gbc.gridwidth = GridBagConstraints.REMAINDER;
	gb.setConstraints( label, gbc );
	add( label );
	}


    /// Show the box.
    public void show()
	{
	pack();
	validate();
	// We have to do the super.show() in another thread, cause for modal
	// dialogs it doesn't return until the dialog goes away.
	(new Thread( this )).start();
	}

    private boolean isDone = false;

    public void run()
	{
	if ( ! isDone )
	    super.show();
	}

    /// Task is done, get rid of the busy-box.
    public void done()
	{
	isDone = true;
	hide();
	//setVisible( false );
	dispose();
	}

    }