lwlayer.java

Zaval Light-Weight Visual Components Library (LwVCL) is a pure Java alternative to humble AWT-based

/**
 *     Caption: Zaval Light-Weight Visual Components Library
 *     $Revision: 2.79 $
 *     $Date: 2003/08/22 11:24:16 $
 *
 *     @author:     Andrei Vishnevsky
 *     @version:    3.50
 *
 * Zaval Light-Weight Visual Components Library (LwVCL) is a pure Java
 * alternative to humble AWT-based and SWING-based GUI interfaces for
 * wide ranges of platforms, including J2SE, PersonalJava and J2ME.
 *
 * Designed as light-weight but, alternatively to Swing, built separately
 * from AWT (not on top of the java.awt library like Swing), the LwVCL is
 * the good alternative to highly performant, memory-efficient, flexible
 * GUI solution for embedded, stand-alone and applet applications.
 *
 * For more info on this product read Zaval Light-Weight Visual Components Library Tutorial
 * (It comes within this package).
 * The latest product version is always available from the product's homepage:
 * http://www.zaval.org/products/lwvcl/
 * and from the SourceForge:
 * http://sourceforge.net/projects/zaval0003/
 *
 * Contacts:
 *   Support : [e-mail]
 *   Change Requests : [e-mail]
 *   Feedback : [e-mail]
 *   Other : [e-mail]
 *
 * Copyright (C) 2001-2003  Zaval Creative Engineering Group (http://www.zaval.org)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * (version 2) as published by the Free Software Foundation.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */
package org.zaval.lw;

import java.awt.*;

/**
 * This layer class is a special container that is used as the LwDesktop children.
 * Desktop consists of the layers. Every layer is laid out by the desktop to place all
 * desktop room. When an event is performed the desktop "asks" the layers starting from the
 * tail layer if it is ready to get the event and delivers the event to the first-found
 * layer. The layered structure of the desktop allows to implement additional features
 * (for example, internal frame) basing on the LwVCL level.
 */
public class LwLayer
extends LwPanel
{
   private LwComponent prevFocusOwner;
   private Object id;

 /**
  * Constructs the layer with the specified id.
  * @param <code>id</code> the specified id.
  */
  public LwLayer(Object id) {
     if (id  == null) throw new IllegalArgumentException();
     this.id = id;
   }

  /**
   * Gets the layer id.
   * @return the layer id
   */
   public /*C#virtual*/ Object getID () {
     return id;
   }

  /**
   * Invoked whenever the desktop lost focus.
   */
   public /*C#virtual*/ void releaseFocus()  {
     prevFocusOwner = LwFocusManager.manager.getFocusOwner();
     LwFocusManager.manager.requestFocus(null);
   }

  /**
   * Invoked whenever the desktop got focus.
   */
   public /*C#virtual*/ void setupFocus() {
     if (prevFocusOwner != null) LwFocusManager.manager.requestFocus(prevFocusOwner);
     else LwFocusManager.manager.requestFocus(LwFocusManager.manager.findFocusable(this));
   }

  /**
   * Invoked whenever a mouse button has been pressed.
   * @param <code>x</code> the x coordinate of the mouse pointer.
   * @param <code>y</code> the y coordinate of the mouse pointer.
   * @param <code>mask</code> the mask that specifies mouse buttons states.
   */
   public /*C#virtual*/ void mousePressed(int x, int y, int mask) {}

  /**
   * Invoked whenever a key has been pressed.
   * @param <code>keyCode</code> the key code.
   * @param <code>mask</code> the keyboard trigger keys states.
   */
   public /*C#virtual*/ void keyPressed  (int keyCode, int mask) {}

  /**
   * Gets if the layer is active.
   * @return <code>true</code> if the layer is active.
   */
   public /*C#virtual*/ boolean isActive() {
     return true;
   }

  /**
   * Gets if the focus root component.
   * @return a focus root component.
   */
   public /*C#virtual*/ LwComponent getFocusRoot() {
     return this;
   }
}