1 /*
2 * Copyright (c) 2014, 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 package javafx.scene.control;
26
27 import java.lang.ref.WeakReference;
28 import java.util.ArrayList;
29 import java.util.Arrays;
30 import java.util.List;
31 import java.util.Optional;
32
33 import com.sun.javafx.scene.control.skin.AccordionSkin;
34 import com.sun.javafx.scene.control.skin.resources.ControlResources;
35 import javafx.beans.InvalidationListener;
36 import javafx.beans.NamedArg;
37 import javafx.beans.property.ObjectProperty;
38 import javafx.beans.property.SimpleObjectProperty;
39 import javafx.collections.ListChangeListener;
40 import javafx.collections.ObservableList;
41 import javafx.scene.Node;
42 import javafx.scene.image.Image;
43 import javafx.scene.image.ImageView;
44
45 /**
46 * The Alert class subclasses the {@link Dialog} class, and provides support for a number
47 * of pre-built dialog types that can be easily shown to users to prompt for a
48 * response. Therefore, for many users, the Alert class is the most suited class
49 * for their needs (as opposed to using {@link Dialog} directly). Alternatively,
50 * users who want to prompt a user for text input or to make a choice from a list
51 * of options would be better served by using {@link TextInputDialog} and
52 * {@link ChoiceDialog}, respectively.
53 *
54 * <p>When creating an Alert instance, users must pass in an {@link AlertType}
55 * enumeration value. It is by passing in this value that the Alert instance will
56 * configure itself appropriately (by setting default values for many of the
57 * {@link Dialog} properties, including {@link #titleProperty() title},
58 * {@link #headerTextProperty() header}, and {@link #graphicProperty() graphic},
59 * as well as the default {@link #getButtonTypes() buttons} that are expected in
60 * a dialog of the given type.
61 *
62 * <p>To instantiate (but not yet show) an Alert, simply use code such as the following:
63 * {@code Alert alert = new Alert(AlertType.CONFIRMATION, "Are you sure you want to format your system?");}
64 *
65 * <p>Once an Alert is instantiated, we must show it. More often than not, alerts
66 * (and dialogs in general) are shown in a modal and blocking fashion. 'Modal'
67 * means that the dialog prevents user interaction with the owning application
68 * whilst it is showing, and 'blocking' means that code execution stops at the
69 * point in which the dialog is shown. This means that you can show a dialog,
70 * await the user response, and then continue running the code that directly
71 * follows the show call, giving developers the ability to immediately deal with
72 * the user input from the dialog (if relevant).
73 *
74 * <p>JavaFX dialogs are modal by default (you can change this via the
75 * {@link #initModality(javafx.stage.Modality)} API). To specify whether you want
76 * blocking or non-blocking dialogs, developers simply choose to call
77 * {@link #showAndWait()} or {@link #show()} (respectively). By default most
78 * developers should choose to use {@link #showAndWait()}, given the ease of
79 * coding in these situations. Shown below is three code snippets, showing three
80 * equally valid ways of showing the Alert dialog that was specified above:
81 *
82 * <p><strong>Option 1: The 'traditional' approach</strong>
83 * <pre>{@code Optional<ButtonType> result = alert.showAndWait();
84 * if (result.isPresent() && result.get() == ButtonType.OK) {
85 * formatSystem();
86 * }}</pre>
87 *
88 * <p><strong>Option 2: The traditional + Optional approach</strong>
89 * <pre>{@code alert.showAndWait().ifPresent(response -> {
90 * if (response == ButtonType.OK) {
91 * formatSystem();
92 * }
93 * });}</pre>
94 *
95 * <p><strong>Option 3: The fully lambda approach</strong>
96 * <pre>{@code alert.showAndWait()
97 * .filter(response -> response == ButtonType.OK)
98 * .ifPresent(response -> formatSystem());
99 * }</pre>
100 *
101 * <p>There is no better or worse option of the three listed above, so developers
102 * are encouraged to work to their own style preferences. The purpose of showing
103 * the above is to help introduce developers to the {@link Optional} API, which
104 * is new in Java 8 and may be foreign to many developers.
105 *
106 * @see Dialog
107 * @see AlertType
108 * @see TextInputDialog
109 * @see ChoiceDialog
110 * @since JavaFX 8u40
111 */
112 public class Alert extends Dialog<ButtonType> {
113
114 /**************************************************************************
115 *
116 * Static enums
117 *
118 **************************************************************************/
119
120 /**
121 * An enumeration containing the available, pre-built alert types that
122 * the {@link Alert} class can use to pre-populate various properties.
123 *
124 * @since JavaFX 8u40
125 */
126 public static enum AlertType {
127 /**
128 * The NONE alert type has the effect of not setting any default properties
129 * in the Alert.
130 */
131 NONE,
132
133 /**
134 * The INFORMATION alert type configures the Alert dialog to appear in a
135 * way that suggests the content of the dialog is informing the user of
136 * a piece of information. This includes an 'information' image, an
137 * appropriate title and header, and just an OK button for the user to
138 * click on to dismiss the dialog.
139 */
140 INFORMATION,
141
142 /**
143 * The WARNING alert type configures the Alert dialog to appear in a
144 * way that suggests the content of the dialog is warning the user about
145 * some fact or action. This includes a 'warning' image, an
146 * appropriate title and header, and just an OK button for the user to
147 * click on to dismiss the dialog.
148 */
149 WARNING,
150
151 /**
152 * The CONFIRMATION alert type configures the Alert dialog to appear in a
153 * way that suggests the content of the dialog is seeking confirmation from
154 * the user. This includes a 'confirmation' image, an
155 * appropriate title and header, and both OK and Cancel buttons for the
156 * user to click on to dismiss the dialog.
157 */
158 CONFIRMATION,
159
160 /**
161 * The ERROR alert type configures the Alert dialog to appear in a
162 * way that suggests that something has gone wrong. This includes an
163 * 'error' image, an appropriate title and header, and just an OK button
164 * for the user to click on to dismiss the dialog.
165 */
166 ERROR
167 }
168
169
170
171 /**************************************************************************
172 *
173 * Fields
174 *
175 **************************************************************************/
176
177 private WeakReference<DialogPane> dialogPaneRef;
178
179 private boolean installingDefaults = false;
180 private boolean hasCustomButtons = false;
181 private boolean hasCustomTitle = false;
182 private boolean hasCustomHeaderText = false;
183
184 private final InvalidationListener headerTextListener = o -> {
185 if (!installingDefaults) hasCustomHeaderText = true;
186 };
187
188 private final InvalidationListener titleListener = o -> {
189 if (!installingDefaults) hasCustomTitle = true;
190 };
191
192 private final ListChangeListener<ButtonType> buttonsListener = change -> {
193 if (!installingDefaults) hasCustomButtons = true;
194 };
195
196
197
198 /**************************************************************************
199 *
200 * Constructors
201 *
202 **************************************************************************/
203
204 /**
205 * Creates an alert with the given AlertType (refer to the {@link AlertType}
206 * documentation for clarification over which one is most appropriate).
207 *
208 * <p>By passing in an AlertType, default values for the
209 * {@link #titleProperty() title}, {@link #headerTextProperty() headerText},
210 * and {@link #graphicProperty() graphic} properties are set, as well as the
211 * relevant {@link #getButtonTypes() buttons} being installed. Once the Alert
212 * is instantiated, developers are able to modify the values of the alert as
213 * desired.
214 *
215 * <p>It is important to note that the one property that does not have a
216 * default value set, and which therefore the developer must set, is the
217 * {@link #contentTextProperty() content text} property (or alternatively,
218 * the developer may call {@code alert.getDialogPane().setContent(Node)} if
219 * they want a more complex alert). If the contentText (or content) properties
220 * are not set, there is no useful information presented to end users.
221 */
222 public Alert(@NamedArg("alertType") AlertType alertType) {
223 this(alertType, "");
224 }
225
226 /**
227 * Creates an alert with the given contentText, ButtonTypes, and AlertType
228 * (refer to the {@link AlertType} documentation for clarification over which
229 * one is most appropriate).
230 *
231 * <p>By passing in a variable number of ButtonType arguments, the developer
232 * is directly overriding the default buttons that will be displayed in the
233 * dialog, replacing the pre-defined buttons with whatever is specified in the
234 * varargs array.
235 *
236 * <p>By passing in an AlertType, default values for the
237 * {@link #titleProperty() title}, {@link #headerTextProperty() headerText},
238 * and {@link #graphicProperty() graphic} properties are set. Once the Alert
239 * is instantiated, developers are able to modify the values of the alert as
240 * desired.
241 */
242 public Alert(@NamedArg("alertType") AlertType alertType,
243 @NamedArg("contentText") String contentText,
244 ButtonType... buttons) {
245 super();
246
247 final DialogPane dialogPane = getDialogPane();
248 dialogPane.setContentText(contentText);
249 getDialogPane().getStyleClass().add("alert");
250
251 dialogPaneRef = new WeakReference<>(dialogPane);
252
253 hasCustomButtons = buttons != null && buttons.length > 0;
254 if (hasCustomButtons) {
255 for (ButtonType btnType : buttons) {
256 dialogPane.getButtonTypes().addAll(btnType);
257 }
258 }
259
260 setAlertType(alertType);
261
262 // listening to property changes on Dialog and DialogPane
263 dialogPaneProperty().addListener(o -> updateListeners());
264 titleProperty().addListener(titleListener);
265 updateListeners();
266 }
267
268
269
270 /**************************************************************************
271 *
272 * Properties
273 *
274 **************************************************************************/
275
276 /**
277 * When creating an Alert instance, users must pass in an {@link AlertType}
278 * enumeration value. It is by passing in this value that the Alert instance will
279 * configure itself appropriately (by setting default values for many of the
280 * {@link Dialog} properties, including {@link #titleProperty() title},
281 * {@link #headerTextProperty() header}, and {@link #graphicProperty() graphic},
282 * as well as the default {@link #getButtonTypes() buttons} that are expected in
283 * a dialog of the given type.
284 */
285 // --- alertType
286 private final ObjectProperty<AlertType> alertType = new SimpleObjectProperty<AlertType>(null) {
287 final String[] styleClasses = new String[] { "information", "warning", "error", "confirmation" };
288
289 protected void invalidated() {
290 String newTitle = "";
291 String newHeader = "";
292 // Node newGraphic = null;
293 String styleClass = "";
294 ButtonType[] newButtons = new ButtonType[] { ButtonType.OK };
295 switch (getAlertType()) {
296 case NONE: {
297 newButtons = new ButtonType[] { };
298 break;
299 }
300 case INFORMATION: {
301 newTitle = ControlResources.getString("Dialog.info.title");
302 newHeader = ControlResources.getString("Dialog.info.header");
303 styleClass = "information";
304 break;
305 }
306 case WARNING: {
307 newTitle = ControlResources.getString("Dialog.warning.title");
308 newHeader = ControlResources.getString("Dialog.warning.header");
309 styleClass = "warning";
310 break;
311 }
312 case ERROR: {
313 newTitle = ControlResources.getString("Dialog.error.title");
314 newHeader = ControlResources.getString("Dialog.error.header");
315 styleClass = "error";
316 break;
317 }
318 case CONFIRMATION: {
319 newTitle = ControlResources.getString("Dialog.confirm.title");
320 newHeader = ControlResources.getString("Dialog.confirm.header");
321 styleClass = "confirmation";
322 newButtons = new ButtonType[] { ButtonType.OK, ButtonType.CANCEL };
323 break;
324 }
325 }
326
327 installingDefaults = true;
328 if (!hasCustomTitle) setTitle(newTitle);
329 if (!hasCustomHeaderText) setHeaderText(newHeader);
330 if (!hasCustomButtons) getButtonTypes().setAll(newButtons);
331
332 // update the style class based on the alert type. We use this to
333 // specify the default graphic to use (i.e. via CSS).
334 DialogPane dialogPane = getDialogPane();
335 if (dialogPane != null) {
336 List<String> toRemove = new ArrayList<>(Arrays.asList(styleClasses));
337 toRemove.remove(styleClass);
338 dialogPane.getStyleClass().removeAll(toRemove);
339 if (! dialogPane.getStyleClass().contains(styleClass)) {
340 dialogPane.getStyleClass().add(styleClass);
341 }
342 }
343
344 installingDefaults = false;
345 }
346 };
347
348 public final AlertType getAlertType() {
349 return alertType.get();
350 }
351
352 public final void setAlertType(AlertType alertType) {
353 this.alertType.setValue(alertType);
354 }
355
356 public final ObjectProperty<AlertType> alertTypeProperty() {
357 return alertType;
358 }
359
360
361 /**
362 * Returns an {@link ObservableList} of all {@link ButtonType} instances that
363 * are currently set inside this Alert instance. A ButtonType may either be one
364 * of the pre-defined types (e.g. {@link ButtonType#OK}), or it may be a
365 * custom type (created via the {@link ButtonType#ButtonType(String)} or
366 * {@link ButtonType#ButtonType(String, javafx.scene.control.ButtonBar.ButtonData)}
367 * constructors.
368 *
369 * <p>Readers should refer to the {@link ButtonType} class documentation for more details,
370 * but at a high level, each ButtonType instance is converted to
371 * a Node (although most commonly a {@link Button}) via the (overridable)
372 * {@link DialogPane#createButton(ButtonType)} method on {@link DialogPane}.
373 */
374 // --- buttonTypes
375 public final ObservableList<ButtonType> getButtonTypes() {
376 return getDialogPane().getButtonTypes();
377 }
378
379
380
381 /**************************************************************************
382 *
383 * Private Implementation
384 *
385 **************************************************************************/
386
387 private void updateListeners() {
388 DialogPane oldPane = dialogPaneRef.get();
389
390 if (oldPane != null) {
391 oldPane.headerTextProperty().removeListener(headerTextListener);
392 oldPane.getButtonTypes().removeListener(buttonsListener);
393 }
394
395 // listen to changes to properties that would be changed by alertType being
396 // changed, so that we only change values that are still at their default
397 // value (i.e. the user hasn't changed them, so we are free to set them
398 // to a new default value when the alertType changes).
399
400 DialogPane newPane = getDialogPane();
401 if (newPane != null) {
402 newPane.headerTextProperty().addListener(headerTextListener);
403 newPane.getButtonTypes().addListener(buttonsListener);
404 }
405
406 dialogPaneRef = new WeakReference<DialogPane>(newPane);
407 }
408 }