windowevent.java

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/*
 * @(#)WindowEvent.java	1.30 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt.event;

import java.awt.Component;
import java.awt.Event;
import java.awt.Window;

import sun.awt.AppContext;
import sun.awt.SunToolkit;

/**
 * A low-level event that indicates that a window has changed its status. This
 * low-level event is generated by a Window object when it is opened, closed,
 * activated, deactivated, iconified, or deiconified, or when focus is
 * transfered into or out of the Window.
 * <P>
 * The event is passed to every <code>WindowListener</code>
 * or <code>WindowAdapter</code> object which registered to receive such
 * events using the window's <code>addWindowListener</code> method.
 * (<code>WindowAdapter</code> objects implement the
 * <code>WindowListener</code> interface.) Each such listener object
 * gets this <code>WindowEvent</code> when the event occurs.
 *
 * @author Carl Quinn
 * @author Amy Fowler
 * @version 1.30, 01/23/03
 *
 * @see WindowAdapter
 * @see WindowListener
 * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/windowlistener.html">Tutorial: Writing a Window Listener</a>
 * @see <a href="http://www.awl.com/cp/javaseries/jcl1_2.html">Reference: The Java Class Libraries (update file)</a>
 *
 * @since JDK1.1
 */
public class WindowEvent extends ComponentEvent {

    /**
     * The first number in the range of ids used for window events.
     */
    public static final int WINDOW_FIRST        = 200;

    /**
     * The window opened event.  This event is delivered only
     * the first time a window is made visible.
     */
    public static final int WINDOW_OPENED	= WINDOW_FIRST; // 200

    /**
     * The "window is closing" event. This event is delivered when
     * the user attempts to close the window from the window's system menu.  
     * If the program does not explicitly hide or dispose the window
     * while processing this event, the window close operation will be
     * cancelled.
     */
    public static final int WINDOW_CLOSING	= 1 + WINDOW_FIRST; //Event.WINDOW_DESTROY

    /**
     * The window closed event. This event is delivered after
     * the window has been closed as the result of a call to dispose.
     */
    public static final int WINDOW_CLOSED	= 2 + WINDOW_FIRST;

    /**
     * The window iconified event. This event is delivered when
     * the window has been changed from a normal to a minimized state.
     * For many platforms, a minimized window is displayed as
     * the icon specified in the window's iconImage property.
     * @see java.awt.Frame#setIconImage
     */
    public static final int WINDOW_ICONIFIED	= 3 + WINDOW_FIRST; //Event.WINDOW_ICONIFY

    /**
     * The window deiconified event type. This event is delivered when
     * the window has been changed from a minimized to a normal state.
     */
    public static final int WINDOW_DEICONIFIED	= 4 + WINDOW_FIRST; //Event.WINDOW_DEICONIFY

    /**
     * The window-activated event type. This event is delivered when the Window
     * becomes the active Window. Only a Frame or a Dialog can be the active
     * Window. The native windowing system may denote the active Window or its
     * children with special decorations, such as a highlighted title bar. The
     * active Window is always either the focused Window, or the first Frame or
     * Dialog that is an owner of the focused Window.
     */
    public static final int WINDOW_ACTIVATED	= 5 + WINDOW_FIRST;

    /**
     * The window-deactivated event type. This event is delivered when the
     * Window is no longer the active Window. Only a Frame or a Dialog can be
     * the active Window. The native windowing system may denote the active
     * Window or its children with special decorations, such as a highlighted
     * title bar. The active Window is always either the focused Window, or the
     * first Frame or Dialog that is an owner of the focused Window.
     */
    public static final int WINDOW_DEACTIVATED	= 6 + WINDOW_FIRST;

    /**
     * The window-gained-focus event type. This event is delivered when the
     * Window becomes the focused Window, which means that the Window, or one
     * of its subcomponents, will receive keyboard events.
     */
    public static final int WINDOW_GAINED_FOCUS = 7 + WINDOW_FIRST;

    /**
     * The window-lost-focus event type. This event is delivered when a Window
     * is no longer the focused Window, which means keyboard events will no
     * longer be delivered to the Window or any of its subcomponents.
     */
    public static final int WINDOW_LOST_FOCUS   = 8 + WINDOW_FIRST;

    /**
     * The window-state-changed event type.  This event is delivered
     * when a Window's state is changed by virtue of it being
     * iconified, maximized etc.
     * @since 1.4
     */
    public static final int WINDOW_STATE_CHANGED = 9 + WINDOW_FIRST;

    /**
     * The last number in the range of ids used for window events.
     */
    public static final int WINDOW_LAST         = WINDOW_STATE_CHANGED;

    /**
     * The other Window involved in this focus or activation change. For a
     * WINDOW_ACTIVATED or WINDOW_GAINED_FOCUS event, this is the Window that
     * lost activation or focus. For a WINDOW_DEACTIVATED or WINDOW_LOST_FOCUS
     * event, this is the Window that gained activation or focus. For any other
     * type of WindowEvent, or if the focus or activation change occurs with a
     * native application, a Java application in a different VM, or with no
     * other Window, null is returned.
     *
     * @see #getOppositeWindow
     * @since 1.4
     */
    transient Window opposite;

    /**
     * TBS
     */ 
    int oldState;
    int newState;


    /*
     * JDK 1.1 serialVersionUID
     */
    private static final long serialVersionUID = -1567959133147912127L;


    /**
     * Constructs a <code>WindowEvent</code> object.
     *
     * @param source	the <code>Window</code> object
     *                    that originated the event
     * @param id        an integer indicating the type of event.
     * @param opposite  the other window involved in the focus or activation
     *                      change, or <code>null</code>
     * @param oldState  previous state of the window for window state
     *                      change event
     * @param newState  new state of the window for window state change event
     * @since 1.4
     */
    public WindowEvent(Window source, int id, Window opposite,
		       int oldState, int newState)
    {
        super(source, id);
	this.opposite = opposite;
	this.oldState = oldState;
	this.newState = newState;
    }

    /**
     * Constructs a <code>WindowEvent</code> object with the
     * specified opposite <code>Window</code>. The opposite
     * <code>Window</code> is the other <code>Window</code>
     * involved in this focus or activation change.
     * For a <code>WINDOW_ACTIVATED</code> or
     * <code>WINDOW_GAINED_FOCUS</code> event, this is the
     * <code>Window</code> that lost activation or focus.
     * For a <code>WINDOW_DEACTIVATED</code> or
     * <code>WINDOW_LOST_FOCUS</code> event, this is the
     * <code>Window</code> that gained activation or focus.
     * If this focus change occurs with a native application, with a
     * Java application in a different VM, or with no other
     * <code>Window</code>, then the opposite Window is <code>null</code>.
     * <p>Note that passing in an invalid <code>id</code> results in
     * unspecified behavior.
     *
     * @param source     the <code>Window</code> object that
     *                   originated the event
     * @param id         <code>WINDOW_ACTIVATED</code>,
     *                   <code>WINDOW_DEACTIVATED</code>,
     *                   <code>WINDOW_GAINED_FOCUS</code>,
     *                   or <code>WINDOW_LOST_FOCUS</code>. It is
     *                   expected that this constructor will not be used for
     *                   other <code>WindowEvent</code> types because the
     *                   opposite <code>Window</code> of such events
     *                   will always be <code>null</code>
     * @param opposite   the other <code>Window</code> involved in the
     *                   focus or activation change, or <code>null</code>
     */
    public WindowEvent(Window source, int id, Window opposite) {
        this(source, id, opposite, 0, 0);
    }

    /**
     * Constructs a <code>WindowEvent</code> object with the specified
     * previous and new window states.
     * 
     * @param source	the <code>Window</code> object
     *                  that originated the event
     * @param id	<code>WINDOW_STATE_CHANGED</code> event type.
     *                  It is expected that this constructor will not
     *                  be used for other <code>WindowEvent</code>
     *                  types, because the previous and new window
     *                  states are meaningless for other event types.
     * @param oldState	an integer representing the previous window state
     * @param newState	an integer representing the new window state
     * @since 1.4
     */
    public WindowEvent(Window source, int id, int oldState, int newState) {
	this(source, id, null, oldState, newState);
    }

    /**
     * Constructs a <code>WindowEvent</code> object.
     * <p>Note that passing in an invalid <code>id</code> results in
     * unspecified behavior.
     *
     * @param source the <code>Window</code> object that originated the event
     * @param id     an integer indicating the type of event
     */
    public WindowEvent(Window source, int id) {
        this(source, id, null, 0, 0);
    }

    /**
     * Returns the originator of the event.
     *
     * @return the Window object that originated the event
     */
    public Window getWindow() {
        return (source instanceof Window) ? (Window)source : null;
    }

    /**
     * Returns the other Window involved in this focus or activation change.
     * For a WINDOW_ACTIVATED or WINDOW_GAINED_FOCUS event, this is the Window
     * that lost activation or focus. For a WINDOW_DEACTIVATED or
     * WINDOW_LOST_FOCUS event, this is the Window that gained activation or
     * focus. For any other type of WindowEvent, or if the focus or activation
     * change occurs with a native application, with a Java application in a
     * different VM or context, or with no other Window, null is returned.
     *
     * @return the other Window involved in the focus or activation change, or
     *         null
     * @since 1.4
     */
    public Window getOppositeWindow() {
        if (opposite == null) {
	    return null;
	}

        return (SunToolkit.targetToAppContext(opposite) ==
		AppContext.getAppContext())
	    ? opposite
	    : null;
    }

    /**
     * For <code>WINDOW_STATE_CHANGED</code> events returns the
     * previous state of the window. The state is
     * represented as a bitwise mask.
     * <ul>
     * <li><code>NORMAL</code>
     * <br>Indicates that no state bits are set.
     * <li><code>ICONIFIED</code>
     * <li><code>MAXIMIZED_HORIZ</code>
     * <li><code>MAXIMIZED_VERT</code>
     * <li><code>MAXIMIZED_BOTH</code>
     * <br>Concatenates <code>MAXIMIZED_HORIZ</code>
     * and <code>MAXIMIZED_VERT</code>.
     * </ul>
     *
     * @return a bitwise mask of the previous window state
     * @see java.awt.Frame#getExtendedState()
     * @since 1.4
     */
    public int getOldState() {
	return oldState;
    }

    /**
     * For <code>WINDOW_STATE_CHANGED</code> events returns the
     * new state of the window. The state is
     * represented as a bitwise mask.
     * <ul>
     * <li><code>NORMAL</code>
     * <br>Indicates that no state bits are set.
     * <li><code>ICONIFIED</code>
     * <li><code>MAXIMIZED_HORIZ</code>
     * <li><code>MAXIMIZED_VERT</code>
     * <li><code>MAXIMIZED_BOTH</code>
     * <br>Concatenates <code>MAXIMIZED_HORIZ</code>
     * and <code>MAXIMIZED_VERT</code>.
     * </ul>
     *
     * @return a bitwise mask of the new window state
     * @see java.awt.Frame#getExtendedState()
     * @since 1.4
     */
    public int getNewState() {
	return newState;
    }

    /**
     * Returns a parameter string identifying this event.
     * This method is useful for event-logging and for debugging.
     *
     * @return a string identifying the event and its attributes
     */
    public String paramString() {
        String typeStr;
        switch(id) {
          case WINDOW_OPENED:
              typeStr = "WINDOW_OPENED";
              break;
          case WINDOW_CLOSING:
              typeStr = "WINDOW_CLOSING";
              break;
          case WINDOW_CLOSED:
              typeStr = "WINDOW_CLOSED";
              break;
          case WINDOW_ICONIFIED:
              typeStr = "WINDOW_ICONIFIED";
              break;
          case WINDOW_DEICONIFIED:
              typeStr = "WINDOW_DEICONIFIED";
              break;
          case WINDOW_ACTIVATED:
              typeStr = "WINDOW_ACTIVATED";
              break;
          case WINDOW_DEACTIVATED:
              typeStr = "WINDOW_DEACTIVATED";
              break;
	  case WINDOW_GAINED_FOCUS:
	      typeStr = "WINDOW_GAINED_FOCUS";
	      break;
	  case WINDOW_LOST_FOCUS:
	      typeStr = "WINDOW_LOST_FOCUS";
	      break;
	  case WINDOW_STATE_CHANGED:
	      typeStr = "WINDOW_STATE_CHANGED";
	      break;
          default:
              typeStr = "unknown type";
        }
	return typeStr + ",opposite=" + getOppositeWindow()
	    + ",oldState=" + oldState + ",newState=" + newState;
    }
}