Source code: org/greenstone/gatherer/gui/ModalDialog.java
1 /*
2 * ModalDialog
3 *
4 * GLI 2.3c
5 *
6 * 30May2003
7 *
8 *#########################################################################
9 *
10 * A component of the Gatherer application, part of the Greenstone digital
11 * library suite from the New Zealand Digital Library Project at the
12 * University of Waikato, New Zealand.
13 *
14 * Author: John Thompson, Greenstone Digital Library, University of Waikato
15 *
16 * Copyright (C) 1999 New Zealand Digital Library Project
17 *
18 * This program is free software; you can redistribute it and/or modify
19 * it under the terms of the GNU General Public License as published by
20 * the Free Software Foundation; either version 2 of the License, or
21 * (at your option) any later version.
22 *
23 * This program is distributed in the hope that it will be useful,
24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
26 * GNU General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program; if not, write to the Free Software
30 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31 *########################################################################
32 */
33 package org.greenstone.gatherer.gui;
34
35 import java.awt.*;
36 import javax.swing.*;
37 /** An extension of the JDialog that overrides the JVM's typical modal behaviour. This typical behaviour is that when a modal dialog is opened, all other windows cease to respond to user events until the modal dialog is disposed. However this prevents us opening the help documents property whenever a modal dialog is open. Thus we override the modal behaviour so that only the owner frame or dialog is blocked.
38 * Note that because we always call the super constructor with modal set to false, this should be made visible with setVisible(true) rather than show() which will return straight away. */
39 public class ModalDialog
40 extends JDialog {
41 /** true if this dialog should be modal, ie block user actions to its owner window, false otherwise. */
42 protected boolean modal = false;
43 /** true if this dialog is currently waiting some thread. */
44 protected boolean waiting = false;
45
46 /** Constructor.
47 */
48 public ModalDialog() {
49 super((Frame)null, "", false);
50 }
51
52 /** Constructor.
53 * @param parent the Dialog which is the owener of this dialog.
54 */
55 public ModalDialog(Dialog parent) {
56 super(parent, "", false);
57 }
58
59 /** Constructor.
60 * @param parent the Dialog which is the owener of this dialog.
61 * @param modal true if this dialog should be modal, ie block user actions to its owner window, false otherwise.
62 */
63 public ModalDialog(Dialog parent, boolean modal) {
64 super(parent, "", false);
65 this.modal = modal;
66 }
67
68 /** Constructor.
69 * @param parent the Dialog which is the owner of this dialog.
70 * @param title the String to use as the title for this dialog.
71 */
72 public ModalDialog(Dialog parent, String title) {
73 super (parent, title, false);
74 this.modal = false;
75 }
76
77 /** Constructor.
78 * @param parent the Dialog which is the owener of this dialog.
79 * @param title the String to use as the title for this dialog.
80 * @param modal true if this dialog should be modal, ie block user actions to its owner window, false otherwise.
81 */
82 public ModalDialog(Dialog parent, String title, boolean modal) {
83 super (parent, title, false);
84 this.modal = modal;
85 }
86
87 /** Constructor.
88 * @param parent the Frame which is the owener of this dialog.
89 */
90 public ModalDialog(Frame parent) {
91 super(parent, "", false);
92 }
93
94 /** Constructor.
95 * @param parent the Frame which is the owener of this dialog.
96 * @param title the String to use as the title for this dialog.
97 */
98 public ModalDialog(Frame parent, boolean modal) {
99 super(parent, "", false);
100 this.modal = modal;
101
102 }
103
104 /** Constructor.
105 * @param parent the Frame which is the owner of this dialog.
106 * @param title the String to use as the title for this dialog.
107 */
108 public ModalDialog(Frame parent, String title) {
109 super (parent, title, false);
110 }
111
112 /** Constructor.
113 * @param parent the Frame which is the owener of this dialog.
114 * @param title the String to use as the title for this dialog.
115 * @param modal true if this dialog should be modal, ie block user actions to its owner window, false otherwise.
116 */
117 public ModalDialog(Frame parent, String title, boolean modal) {
118 super (parent, title, false);
119 this.modal = modal;
120 }
121
122 /** The set visible method is overriden to provide modal functionality. It essentially hijacks control of the event dispatch thread while the dialog is open, only allowing non-user events to be passed to the parent dialog. Furthermore it only has this effect within the current AWT component tree by utilitizing the TreeLock.
123 * @param visible true if this dialog should be painted on-screen, false otherwise.
124 */
125 public void setVisible (boolean visible) {
126 ///ystem.err.println("setVisible(" + visible + ")");
127 getParent ().setEnabled (!(visible && modal));
128 super.setVisible (visible);
129 if (modal && visible) {
130 try {
131 if (SwingUtilities.isEventDispatchThread ()) {
132 ///ystem.err.println("is Event Dispatch Thread. Only process certain events.");
133 EventQueue theQueue = getToolkit().getSystemEventQueue();
134 while (isVisible ()) {
135 AWTEvent event = theQueue.getNextEvent();
136 Object src = event.getSource ();
137 if (event instanceof ActiveEvent) {
138 ///ystem.err.println("ActiveEvent:");
139 ((ActiveEvent) event).dispatch ();
140 } else if (src instanceof Component) {
141 ///ystem.err.println("Source is component");
142 ((Component) src).dispatchEvent (event);
143 }
144 else {
145 ///ystem.err.println("Event blocked");
146 }
147 }
148 ///ystem.err.println("No longer visible - AWT");
149 } else synchronized (getTreeLock ()) {
150 ///ystem.err.println("is other Thread. Block all events.");
151 while (isVisible ()) {
152 try {
153 waiting = true;
154 getTreeLock().wait();
155 waiting = false;
156 } catch (InterruptedException e) {
157 ///ystem.err.println("Interrupted!!!");
158 break;
159 }
160 }
161 ///ystem.err.println("No longer visible - Other");
162 }
163 } catch (Exception ex) {
164 ex.printStackTrace();
165 }
166 }
167 else if(modal && !visible && waiting) {
168 ///ystem.err.println("Hiding dialog. Tree lock is: " + getTreeLock());
169 synchronized(getTreeLock()) {
170 ///ystem.err.println("Notify!");
171 getTreeLock().notify();
172 }
173 }
174 else if(modal && !waiting) {
175 ///ystem.err.println("Modal Dialog is not currently waiting.");
176 }
177 else if(!modal) {
178 ///ystem.err.println("Dialog is not modal.");
179 }
180 }
181
182 /** Overridden method so we can control modality and not rely on the Dialog default.
183 * @param modal true if this dialog should be modal, ie block user actions to its owner window, false otherwise.
184 */
185 public void setModal (boolean modal) {
186 this.modal = modal;
187 }
188 }