Popup


1   /*
2    * @(#)Popup.java   1.17 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package javax.swing;
9   
10  import java.awt.*;
11  import sun.awt.ModalExclude;
12  
13  /**
14   * Popups are used to display a <code>Component</code> to the user, typically
15   * on top of all the other <code>Component</code>s in a particular containment
16   * hierarchy. <code>Popup</code>s have a very small life cycle. Once you
17   * have obtained a <code>Popup</code>, and hidden it (invoked the
18   * <code>hide</code> method), you should no longer
19   * invoke any methods on it. This allows the <code>PopupFactory</code> to cache
20   * <code>Popup</code>s for later use.
21   * <p>
22   * The general contract is that if you need to change the size of the
23   * <code>Component</code>, or location of the <code>Popup</code>, you should
24   * obtain a new <code>Popup</code>.
25   * <p>
26   * <code>Popup</code> does not descend from <code>Component</code>, rather
27   * implementations of <code>Popup</code> are responsible for creating
28   * and maintaining their own <code>Component</code>s to render the
29   * requested <code>Component</code> to the user.
30   * <p>
31   * You typically do not explicitly create an instance of <code>Popup</code>,
32   * instead obtain one from a <code>PopupFactory</code>.
33   *
34   * @see PopupFactory
35   *
36   * @version 1.17 12/19/03
37   * @since 1.4
38   */
39  public class Popup {
40      /**
41       * The Component representing the Popup.
42       */
43      private Component component;
44  
45      /**
46       * Creates a <code>Popup</code> for the Component <code>owner</code>
47       * containing the Component <code>contents</code>. <code>owner</code>
48       * is used to determine which <code>Window</code> the new
49       * <code>Popup</code> will parent the <code>Component</code> the
50       * <code>Popup</code> creates to.
51       * A null <code>owner</code> implies there is no valid parent.
52       * <code>x</code> and
53       * <code>y</code> specify the preferred initial location to place
54       * the <code>Popup</code> at. Based on screen size, or other paramaters,
55       * the <code>Popup</code> may not display at <code>x</code> and
56       * <code>y</code>.
57       *
58       * @param owner    Component mouse coordinates are relative to, may be null
59       * @param contents Contents of the Popup
60       * @param x        Initial x screen coordinate
61       * @param y        Initial y screen coordinate
62       * @exception IllegalArgumentException if contents is null
63       */
64      protected Popup(Component owner, Component contents, int x, int y) {
65          this();
66          if (contents == null) {
67              throw new IllegalArgumentException  ("Contents must be non-null");
68          }
69          reset(owner, contents, x, y);
70      }
71  
72      /**
73       * Creates a <code>Popup</code>. This is provided for subclasses.
74       */
75      protected Popup() {
76      }
77  
78      /**
79       * Makes the <code>Popup</code> visible. If the <code>Popup</code> is
80       * currently visible, this has no effect.
81       */
82      public void show() {
83          Component component = getComponent();
84  
85          if (component != null) {
86              component.show();
87          }
88      }
89  
90      /**
91       * Hides and disposes of the <code>Popup</code>. Once a <code>Popup</code>
92       * has been disposed you should no longer invoke methods on it. A
93       * <code>dispose</code>d <code>Popup</code> may be reclaimed and later used
94       * based on the <code>PopupFactory</code>. As such, if you invoke methods
95       * on a <code>disposed</code> <code>Popup</code>, indeterminate
96       * behavior will result.
97       */
98      public void hide() {
99          Component component = getComponent();
100 
101         if (component instanceof JWindow  ) {
102             component.hide();
103             ((JWindow  )component).getContentPane().removeAll();
104         }
105         dispose();
106     }
107 
108     /**
109      * Frees any resources the <code>Popup</code> may be holding onto.
110      */
111     void dispose() {
112         Component component = getComponent();
113 
114         if (component instanceof JWindow  ) {
115             ((Window)component).dispose();
116             component = null;
117         }
118     }
119 
120     /**
121      * Resets the <code>Popup</code> to an initial state.
122      */
123     void reset(Component owner, Component contents, int ownerX, int ownerY) {
124         if (getComponent() == null) {
125             component = createComponent(owner);
126         }
127 
128         Component c = getComponent();
129 
130         if (c instanceof JWindow  ) {
131             JWindow   component = (JWindow  )getComponent();
132 
133             component.setLocation(ownerX, ownerY);
134             component.getContentPane().add(contents, BorderLayout.CENTER);
135             contents.invalidate();
136             if(component.isVisible()) {
137                 // Do not call pack() if window is not visible to
138                 // avoid early native peer creation
139                 pack();
140             }
141         }
142     }
143 
144 
145     /**
146      * Causes the <code>Popup</code> to be sized to fit the preferred size
147      * of the <code>Component</code> it contains.
148      */
149     void pack() {
150         Component component = getComponent();
151 
152         if (component instanceof Window) {
153             ((Window)component).pack();
154         }
155     }
156 
157     /**
158      * Returns the <code>Window</code> to use as the parent of the
159      * <code>Window</code> created for the <code>Popup</code>. This creates
160      * a new <code>Frame</code> each time it is invoked. Subclasses that wish
161      * to support a different <code>Window</code> parent should override
162      * this.
163      */
164     private Window getParentWindow(Component owner) {
165         Window window = null;
166 
167         if (owner instanceof Window) {
168             window = (Window)owner;
169         }
170         else if (owner != null) {
171             window = SwingUtilities.getWindowAncestor(owner);
172         }
173         if (window == null) {
174             window = new DefaultFrame();
175         }
176         return window;
177     }
178 
179     /**
180      * Creates the Component to use as the parent of the <code>Popup</code>.
181      * The default implementation creates a <code>Window</code>, subclasses
182      * should override.
183      */
184     Component createComponent(Component owner) {
185         if (GraphicsEnvironment.isHeadless()) {
186             // Generally not useful, bail.
187             return null;
188         }
189         return new HeavyWeightWindow(getParentWindow(owner));
190     }
191 
192     /**
193      * Returns the <code>Component</code> returned from
194      * <code>createComponent</code> that will hold the <code>Popup</code>.
195      */
196     Component getComponent() {
197         return component;
198     }
199 
200 
201     /**
202      * Component used to house window.
203      */
204     static class HeavyWeightWindow extends JWindow   implements ModalExclude {
205         HeavyWeightWindow(Window parent) {
206             super(parent);
207             setFocusableWindowState(false);
208             setName("###overrideRedirect###");
209         }
210 
211         public void update(Graphics g) {
212             paint(g);
213         }
214 
215     public void show() {
216         this.pack();
217         super.show();
218     }
219     }
220 
221 
222     /**
223      * Used if no valid Window ancestor of the supplied owner is found.
224      * <p>
225      * PopupFactory uses this as a way to know when the Popup shouldn't
226      * be cached based on the Window.
227      */
228     static class DefaultFrame extends Frame {
229     }
230 }
231
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