1 /*
2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.swing;
27
28 import java.awt.BorderLayout;
29 import java.awt.Component;
30 import java.awt.Frame;
31 import java.awt.Graphics;
32 import java.awt.GraphicsEnvironment;
33 import java.awt.Window;
34
35 import sun.awt.ModalExclude;
36
37 /**
38 * Popups are used to display a <code>Component</code> to the user, typically
39 * on top of all the other <code>Component</code>s in a particular containment
40 * hierarchy. <code>Popup</code>s have a very small life cycle. Once you
41 * have obtained a <code>Popup</code>, and hidden it (invoked the
42 * <code>hide</code> method), you should no longer
43 * invoke any methods on it. This allows the <code>PopupFactory</code> to cache
44 * <code>Popup</code>s for later use.
45 * <p>
46 * The general contract is that if you need to change the size of the
47 * <code>Component</code>, or location of the <code>Popup</code>, you should
48 * obtain a new <code>Popup</code>.
49 * <p>
50 * <code>Popup</code> does not descend from <code>Component</code>, rather
51 * implementations of <code>Popup</code> are responsible for creating
52 * and maintaining their own <code>Component</code>s to render the
53 * requested <code>Component</code> to the user.
54 * <p>
55 * You typically do not explicitly create an instance of <code>Popup</code>,
56 * instead obtain one from a <code>PopupFactory</code>.
57 *
58 * @see PopupFactory
59 *
60 * @since 1.4
61 */
62 public class Popup {
63 /**
64 * The Component representing the Popup.
65 */
66 private Component component;
67
68 /**
69 * Creates a <code>Popup</code> for the Component <code>owner</code>
70 * containing the Component <code>contents</code>. <code>owner</code>
71 * is used to determine which <code>Window</code> the new
72 * <code>Popup</code> will parent the <code>Component</code> the
73 * <code>Popup</code> creates to.
74 * A null <code>owner</code> implies there is no valid parent.
75 * <code>x</code> and
76 * <code>y</code> specify the preferred initial location to place
77 * the <code>Popup</code> at. Based on screen size, or other paramaters,
78 * the <code>Popup</code> may not display at <code>x</code> and
79 * <code>y</code>.
80 *
81 * @param owner Component mouse coordinates are relative to, may be null
82 * @param contents Contents of the Popup
83 * @param x Initial x screen coordinate
84 * @param y Initial y screen coordinate
85 * @exception IllegalArgumentException if contents is null
86 */
87 protected Popup(Component owner, Component contents, int x, int y) {
88 this();
89 if (contents == null) {
90 throw new IllegalArgumentException("Contents must be non-null");
91 }
92 reset(owner, contents, x, y);
93 }
94
95 /**
96 * Creates a <code>Popup</code>. This is provided for subclasses.
97 */
98 protected Popup() {
99 }
100
101 /**
102 * Makes the <code>Popup</code> visible. If the <code>Popup</code> is
103 * currently visible, this has no effect.
104 */
105
106 @SuppressWarnings("deprecation")
107 public void show() {
108 Component component = getComponent();
109
110 if (component != null) {
111 component.show();
112 }
113 }
114
115 /**
116 * Hides and disposes of the <code>Popup</code>. Once a <code>Popup</code>
117 * has been disposed you should no longer invoke methods on it. A
118 * <code>dispose</code>d <code>Popup</code> may be reclaimed and later used
119 * based on the <code>PopupFactory</code>. As such, if you invoke methods
120 * on a <code>disposed</code> <code>Popup</code>, indeterminate
121 * behavior will result.
122 */
123
124 @SuppressWarnings("deprecation")
125 public void hide() {
126 Component component = getComponent();
127
128 if (component instanceof JWindow) {
129 component.hide();
130 ((JWindow)component).getContentPane().removeAll();
131 }
132 dispose();
133 }
134
135 /**
136 * Frees any resources the <code>Popup</code> may be holding onto.
137 */
138 void dispose() {
139 Component component = getComponent();
140 Window window = SwingUtilities.getWindowAncestor(component);
141
142 if (component instanceof JWindow) {
143 ((Window)component).dispose();
144 component = null;
145 }
146 // If our parent is a DefaultFrame, we need to dispose it, too.
147 if (window instanceof DefaultFrame) {
148 window.dispose();
149 }
150 }
151
152 /**
153 * Resets the <code>Popup</code> to an initial state.
154 */
155 void reset(Component owner, Component contents, int ownerX, int ownerY) {
156 if (getComponent() == null) {
157 component = createComponent(owner);
158 }
159
160 Component c = getComponent();
161
162 if (c instanceof JWindow) {
163 JWindow component = (JWindow)getComponent();
164 // Sets the proper location, and resets internal state of the window
165 component.setBounds(ownerX, ownerY, 1, 1);
166 component.getContentPane().add(contents, BorderLayout.CENTER);
167 component.invalidate();
168 component.validate();
169 if(component.isVisible()) {
170 // Do not call pack() if window is not visible to
171 // avoid early native peer creation
172 pack();
173 }
174 }
175 }
176
177
178 /**
179 * Causes the <code>Popup</code> to be sized to fit the preferred size
180 * of the <code>Component</code> it contains.
181 */
182 void pack() {
183 Component component = getComponent();
184
185 if (component instanceof Window) {
186 ((Window)component).pack();
187 }
188 }
189
190 /**
191 * Returns the <code>Window</code> to use as the parent of the
192 * <code>Window</code> created for the <code>Popup</code>. This creates
193 * a new <code>DefaultFrame</code>, if necessary.
194 */
195 private Window getParentWindow(Component owner) {
196 Window window = null;
197
198 if (owner instanceof Window) {
199 window = (Window)owner;
200 }
201 else if (owner != null) {
202 window = SwingUtilities.getWindowAncestor(owner);
203 }
204 if (window == null) {
205 window = new DefaultFrame();
206 }
207 return window;
208 }
209
210 /**
211 * Creates the Component to use as the parent of the <code>Popup</code>.
212 * The default implementation creates a <code>Window</code>, subclasses
213 * should override.
214 */
215 Component createComponent(Component owner) {
216 if (GraphicsEnvironment.isHeadless()) {
217 // Generally not useful, bail.
218 return null;
219 }
220 return new HeavyWeightWindow(getParentWindow(owner));
221 }
222
223 /**
224 * Returns the <code>Component</code> returned from
225 * <code>createComponent</code> that will hold the <code>Popup</code>.
226 */
227 Component getComponent() {
228 return component;
229 }
230
231
232 /**
233 * Component used to house window.
234 */
235 @SuppressWarnings("serial") // Superclass is not serializable across versions
236 static class HeavyWeightWindow extends JWindow implements ModalExclude {
237 HeavyWeightWindow(Window parent) {
238 super(parent);
239 setFocusableWindowState(false);
240 setType(Window.Type.POPUP);
241
242 // Popups are typically transient and most likely won't benefit
243 // from true double buffering. Turn it off here.
244 getRootPane().setUseTrueDoubleBuffering(false);
245 // Try to set "always-on-top" for the popup window.
246 // Applets usually don't have sufficient permissions to do it.
247 // In this case simply ignore the exception.
248 try {
249 setAlwaysOnTop(true);
250 } catch (SecurityException se) {
251 // setAlwaysOnTop is restricted,
252 // the exception is ignored
253 }
254 }
255
256 public void update(Graphics g) {
257 paint(g);
258 }
259
260 @SuppressWarnings("deprecation")
261 public void show() {
262 this.pack();
263 if (getWidth() > 0 && getHeight() > 0) {
264 super.show();
265 }
266 }
267 }
268
269
270 /**
271 * Used if no valid Window ancestor of the supplied owner is found.
272 * <p>
273 * PopupFactory uses this as a way to know when the Popup shouldn't
274 * be cached based on the Window.
275 */
276 @SuppressWarnings("serial") // JDK-implementation class
277 static class DefaultFrame extends Frame {
278 }
279 }