Mercurial > projects > dwt-addons

comparison dwtx/jface/viewers/Viewer.d @ 10:b6c35faf97c8

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Viewers
author Frank Benoit <benoit@tionex.de>
date Mon, 31 Mar 2008 00:47:19 +0200
parents
children 644f1334b451
comparison
equal deleted inserted replaced
9:6c14e54dfc11 10:b6c35faf97c8
1 /*******************************************************************************
2 * Copyright (c) 2000, 2007 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13 module dwtx.jface.viewers.Viewer;
14
15 import dwtx.jface.viewers.IInputSelectionProvider;
16 import dwtx.jface.viewers.ISelectionChangedListener;
17 import dwtx.jface.viewers.SelectionChangedEvent;
18 import dwtx.jface.viewers.ISelection;
19
20 import dwt.events.HelpEvent;
21 import dwt.events.HelpListener;
22 import dwt.widgets.Control;
23 import dwt.widgets.Item;
24 import dwtx.core.runtime.Assert;
25 import dwtx.core.runtime.ListenerList;
26 import dwtx.jface.util.SafeRunnable;
27
28 import dwt.dwthelper.utils;
29
30 /**
31 * A viewer is a model-based adapter on a widget.
32 * <p>
33 * A viewer can be created as an adapter on a pre-existing control (e.g.,
34 * creating a <code>ListViewer</code> on an existing <code>List</code> control).
35 * All viewers also provide a convenience constructor for creating the control.
36 * </p>
37 * <p>
38 * Implementing a concrete viewer typically involves the following steps:
39 * <ul>
40 * <li>
41 * create DWT controls for viewer (in constructor) (optional)
42 * </li>
43 * <li>
44 * initialize DWT controls from input (inputChanged)
45 * </li>
46 * <li>
47 * define viewer-specific update methods
48 * </li>
49 * <li>
50 * support selections (<code>setSelection</code>, <code>getSelection</code>)
51 * </li>
52 * </ul>
53 * </p>
54 */
55 public abstract class Viewer : IInputSelectionProvider {
56
57 /**
58 * List of selection change listeners (element type: <code>ISelectionChangedListener</code>).
59 *
60 * @see #fireSelectionChanged
61 */
62 private ListenerList selectionChangedListeners;
63
64 /**
65 * List of help request listeners (element type: <code>dwt.events.HelpListener</code>).
66 * Help request listeners.
67 *
68 * @see #handleHelpRequest
69 */
70 private ListenerList helpListeners;
71
72 /**
73 * The names of this viewer's properties.
74 * <code>null</code> if this viewer has no properties.
75 *
76 * @see #setData
77 */
78 private String[] keys;
79
80 /**
81 * The values of this viewer's properties.
82 * <code>null</code> if this viewer has no properties.
83 * This array parallels the value of the <code>keys</code> field.
84 *
85 * @see #setData
86 */
87 private Object[] values;
88
89 /**
90 * Remembers whether we've hooked the help listener on the control or not.
91 */
92 private bool helpHooked = false;
93
94 /**
95 * Help listener for the control, created lazily when client's first help listener is added.
96 */
97 private HelpListener helpListener = null;
98
99 /**
100 * Unique key for associating element data with widgets.
101 * @see dwt.widgets.Widget#setData(String, Object)
102 */
103 protected static const String WIDGET_DATA_KEY = "dwtx.jface.viewers.WIDGET_DATA";//$NON-NLS-1$
104
105 /**
106 * Creates a new viewer.
107 */
108 protected this() {
109 selectionChangedListeners = new ListenerList();
110 helpListeners = new ListenerList();
111 }
112
113 /**
114 * Adds a listener for help requests in this viewer.
115 * Has no effect if an identical listener is already registered.
116 *
117 * @param listener a help listener
118 */
119 public void addHelpListener(HelpListener listener) {
120 helpListeners.add(cast(Object)listener);
121 if (!helpHooked) {
122 Control control = getControl();
123 if (control !is null && !control.isDisposed()) {
124 if (this.helpListener is null) {
125 this.helpListener = new class HelpListener {
126 public void helpRequested(HelpEvent event) {
127 handleHelpRequest(event);
128 }
129 };
130 }
131 control.addHelpListener(this.helpListener);
132 helpHooked = true;
133 }
134 }
135 }
136
137 /* (non-Javadoc)
138 * Method declared on ISelectionProvider.
139 */
140 public void addSelectionChangedListener(ISelectionChangedListener listener) {
141 selectionChangedListeners.add(cast(Object)listener);
142 }
143
144 /**
145 * Notifies any help listeners that help has been requested.
146 * Only listeners registered at the time this method is called are notified.
147 *
148 * @param event a help event
149 *
150 * @see HelpListener#helpRequested(dwt.events.HelpEvent)
151 */
152 protected void fireHelpRequested(HelpEvent event) {
153 Object[] listeners = helpListeners.getListeners();
154 for (int i = 0; i < listeners.length; ++i) {
155 (cast(HelpListener) listeners[i]).helpRequested(event);
156 }
157 }
158
159 /**
160 * Notifies any selection changed listeners that the viewer's selection has changed.
161 * Only listeners registered at the time this method is called are notified.
162 *
163 * @param event a selection changed event
164 *
165 * @see ISelectionChangedListener#selectionChanged
166 */
167 protected void fireSelectionChanged(SelectionChangedEvent event) {
168 Object[] listeners = selectionChangedListeners.getListeners();
169 for (int i = 0; i < listeners.length; ++i) {
170 SafeRunnable.run(new class SafeRunnable {
171 ISelectionChangedListener l;
172 SelectionChangedEvent event_;
173 this(){
174 event_=event;
175 l = cast(ISelectionChangedListener) listeners[i];
176 }
177 public void run() {
178 l.selectionChanged(event_);
179 }
180 });
181 }
182 }
183
184 /**
185 * Returns the primary control associated with this viewer.
186 *
187 * @return the DWT control which displays this viewer's content
188 */
189 public abstract Control getControl();
190
191 /**
192 * Returns the value of the property with the given name,
193 * or <code>null</code> if the property is not found.
194 * <p>
195 * The default implementation performs a (linear) search of
196 * an internal table. Overriding this method is generally not
197 * required if the number of different keys is small. If a more
198 * efficient representation of a viewer's properties is required,
199 * override both <code>getData</code> and <code>setData</code>.
200 * </p>
201 *
202 * @param key the property name
203 * @return the property value, or <code>null</code> if
204 * the property is not found
205 */
206 public Object getData(String key) {
207 Assert.isNotNull(key);
208 if (keys is null) {
209 return null;
210 }
211 for (int i = 0; i < keys.length; i++) {
212 if (keys[i].equals(key)) {
213 return values[i];
214 }
215 }
216 return null;
217 }
218
219 /* (non-Javadoc)
220 * Copy-down of method declared on <code>IInputProvider</code>.
221 */
222 public abstract Object getInput();
223
224 /* (non-Javadoc)
225 * Copy-down of method declared on <code>ISelectionProvider</code>.
226 */
227 public abstract ISelection getSelection();
228
229 /**
230 * Handles a help request from the underlying DWT control.
231 * The default behavior is to fire a help request,
232 * with the event's data modified to hold this viewer.
233 * @param event the event
234 *
235 */
236 protected void handleHelpRequest(HelpEvent event) {
237 Object oldData = event.data;
238 event.data = this;
239 fireHelpRequested(event);
240 event.data = oldData;
241 }
242
243 /**
244 * Internal hook method called when the input to this viewer is
245 * initially set or subsequently changed.
246 * <p>
247 * The default implementation does nothing. Subclassers may override
248 * this method to do something when a viewer's input is set.
249 * A typical use is populate the viewer.
250 * </p>
251 *
252 * @param input the new input of this viewer, or <code>null</code> if none
253 * @param oldInput the old input element or <code>null</code> if there
254 * was previously no input
255 */
256 protected void inputChanged(Object input, Object oldInput) {
257 }
258
259 /**
260 * Refreshes this viewer completely with information freshly obtained from this
261 * viewer's model.
262 */
263 public abstract void refresh();
264
265 /**
266 * Removes the given help listener from this viewer.
267 * Has no affect if an identical listener is not registered.
268 *
269 * @param listener a help listener
270 */
271 public void removeHelpListener(HelpListener listener) {
272 helpListeners.remove(cast(Object)listener);
273 if (helpListeners.size() is 0) {
274 Control control = getControl();
275 if (control !is null && !control.isDisposed()) {
276 control.removeHelpListener(this.helpListener);
277 helpHooked = false;
278 }
279 }
280 }
281
282 /* (non-Javadoc)
283 * Method declared on ISelectionProvider.
284 */
285 public void removeSelectionChangedListener(
286 ISelectionChangedListener listener) {
287 selectionChangedListeners.remove(cast(Object)listener);
288 }
289
290 /**
291 * Scrolls the viewer's control down by one item from the given
292 * display-relative coordinates. Returns the newly revealed Item,
293 * or <code>null</code> if no scrolling occurred or if the viewer
294 * doesn't represent an item-based widget.
295 *
296 * @param x horizontal coordinate
297 * @param y vertical coordinate
298 * @return the item scrolled down to
299 */
300 public Item scrollDown(int x, int y) {
301 return null;
302 }
303
304 /**
305 * Scrolls the viewer's control up by one item from the given
306 * display-relative coordinates. Returns the newly revealed Item,
307 * or <code>null</code> if no scrolling occurred or if the viewer
308 * doesn't represent an item-based widget.
309 *
310 * @param x horizontal coordinate
311 * @param y vertical coordinate
312 * @return the item scrolled up to
313 */
314 public Item scrollUp(int x, int y) {
315 return null;
316 }
317
318 /**
319 * Sets the value of the property with the given name to the
320 * given value, or to <code>null</code> if the property is to be
321 * removed. If this viewer has such a property, its value is
322 * replaced; otherwise a new property is added.
323 * <p>
324 * The default implementation records properties in an internal
325 * table which is searched linearly. Overriding this method is generally not
326 * required if the number of different keys is small. If a more
327 * efficient representation of a viewer's properties is required,
328 * override both <code>getData</code> and <code>setData</code>.
329 * </p>
330 *
331 * @param key the property name
332 * @param value the property value, or <code>null</code> if
333 * the property is not found
334 */
335 public void setData(String key, Object value) {
336 Assert.isNotNull(key);
337 /* Remove the key/value pair */
338 if (value is null) {
339 if (keys is null) {
340 return;
341 }
342 int index = 0;
343 while (index < keys.length && !keys[index].equals(key)) {
344 index++;
345 }
346 if (index is keys.length) {
347 return;
348 }
349 if (keys.length is 1) {
350 keys = null;
351 values = null;
352 } else {
353 String[] newKeys = new String[keys.length - 1];
354 Object[] newValues = new Object[values.length - 1];
355 System.arraycopy(keys, 0, newKeys, 0, index);
356 System.arraycopy(keys, index + 1, newKeys, index,
357 newKeys.length - index);
358 System.arraycopy(values, 0, newValues, 0, index);
359 System.arraycopy(values, index + 1, newValues, index,
360 newValues.length - index);
361 keys = newKeys;
362 values = newValues;
363 }
364 return;
365 }
366
367 /* Add the key/value pair */
368 if (keys is null) {
369 keys = [ key ];
370 values = [ value ];
371 return;
372 }
373 for (int i = 0; i < keys.length; i++) {
374 if (keys[i].equals(key)) {
375 values[i] = value;
376 return;
377 }
378 }
379 String[] newKeys = new String[](keys.length + 1);
380 Object[] newValues = new Object[](values.length + 1);
381 System.arraycopy(keys, 0, newKeys, 0, keys.length);
382 System.arraycopy(values, 0, newValues, 0, values.length);
383 newKeys[keys.length] = key;
384 newValues[values.length] = value;
385 keys = newKeys;
386 values = newValues;
387 }
388
389 /**
390 * Sets or clears the input for this viewer.
391 *
392 * @param input the input of this viewer, or <code>null</code> if none
393 */
394 public abstract void setInput(Object input);
395
396 /**
397 * The viewer implementation of this <code>ISelectionProvider</code>
398 * method make the new selection for this viewer without making it visible.
399 * <p>
400 * This method is equivalent to <code>setSelection(selection,false)</code>.
401 * </p>
402 * <p>
403 * Note that some implementations may not be able to set the selection
404 * without also revealing it, for example (as of 3.3) TreeViewer.
405 * </p>
406 */
407 public void setSelection(ISelection selection) {
408 setSelection(selection, false);
409 }
410
411 /**
412 * Sets a new selection for this viewer and optionally makes it visible.
413 * <p>
414 * Subclasses must implement this method.
415 * </p>
416 *
417 * @param selection the new selection
418 * @param reveal <code>true</code> if the selection is to be made
419 * visible, and <code>false</code> otherwise
420 */
421 public abstract void setSelection(ISelection selection, bool reveal);
422 }