|
1
11 package org.eclipse.jdt.internal.ui.text;
12
13 import java.util.HashMap  ;
14 import java.util.Iterator ;
15 import java.util.Map ;
16
17 import org.eclipse.text.edits.MalformedTreeException;
18 import org.eclipse.text.edits.TextEdit;
19
20 import org.eclipse.core.runtime.Assert;
21
22 import org.eclipse.swt.SWT;
23 import org.eclipse.swt.custom.VerifyKeyListener;
24 import org.eclipse.swt.events.VerifyEvent;
25 import org.eclipse.swt.graphics.Point;
26
27 import org.eclipse.jface.text.BadLocationException;
28 import org.eclipse.jface.text.IDocument;
29 import org.eclipse.jface.text.IRegion;
30 import org.eclipse.jface.text.ITextViewer;
31 import org.eclipse.jface.text.ITextViewerExtension;
32 import org.eclipse.jface.text.TextViewer;
33
34 import org.eclipse.jdt.internal.ui.text.TypingRun.ChangeType;
35
36
37
38
50 public class SmartBackspaceManager {
51
52
53
59 public static final class UndoSpec {
60 private final int triggerOffset;
61 private final IRegion selection;
62 private final TextEdit[] undoEdits;
63 private final UndoSpec child;
64 int lives;
65
66
88 public UndoSpec(int triggerOffset, IRegion selection, TextEdit[] edits, int lives, UndoSpec child) {
89 Assert.isLegal(triggerOffset >= 0);
90 Assert.isLegal(selection != null);
91 Assert.isLegal(lives >= 0);
92 Assert.isLegal(edits != null);
93 Assert.isLegal(edits.length > 0);
94 for (int i= 0; i < edits.length; i++) {
95 Assert.isLegal(edits[i] != null);
96 }
97
98 this.triggerOffset= triggerOffset;
99 this.selection= selection;
100 this.undoEdits= edits;
101 this.lives= lives;
102 this.child= child;
103 }
104 }
105
106
107 private class BackspaceListener implements VerifyKeyListener {
108
109
112 public void verifyKey(VerifyEvent event) {
113 if (fViewer != null && isBackspace(event)) {
114 int offset= getCaretOffset();
115 UndoSpec spec= removeEdit(offset);
116 if (spec != null) {
117 try {
118 beginChange();
119 for (int i= 0; i < spec.undoEdits.length; i++) {
120 spec.undoEdits[i].apply(getDocument(), TextEdit.UPDATE_REGIONS);
121 }
122 fViewer.setSelectedRange(spec.selection.getOffset(), spec.selection.getLength());
123 if (spec.child != null)
124 register(spec.child);
125 } catch (MalformedTreeException e) {
126 return;
128 } catch (BadLocationException e) {
129 return;
131 } finally {
132 endChange();
133 }
134 event.doit= false;
135 }
136
137 }
138 }
139
140 private void beginChange() {
141 ITextViewer viewer= fViewer;
142 if (viewer instanceof TextViewer) {
143 TextViewer v= (TextViewer) viewer;
144 v.getRewriteTarget().beginCompoundChange();
145 }
146 }
147
148 private void endChange() {
149 ITextViewer viewer= fViewer;
150 if (viewer instanceof TextViewer) {
151 TextViewer v= (TextViewer) viewer;
152 v.getRewriteTarget().endCompoundChange();
153 }
154 }
155
156 private boolean isBackspace(VerifyEvent event) {
157 return event.doit == true && event.character == SWT.BS && event.stateMask == 0;
158 }
159
160 private int getCaretOffset() {
161 ITextViewer viewer= fViewer;
162 Point point= viewer.getSelectedRange();
163 return point.x;
164 }
165
166 }
167
168 private ITextViewer fViewer;
169 private BackspaceListener fBackspaceListener;
170 private Map fSpecs;
171 private TypingRunDetector fRunDetector;
172 private ITypingRunListener fRunListener;
173
174
180 public void register(UndoSpec spec) {
181 if (fViewer == null)
182 throw new IllegalStateException ();
183
184 ensureListenerInstalled();
185 addEdit(spec);
186 }
187
188 private void addEdit(UndoSpec spec) {
189 Integer i= new Integer (spec.triggerOffset);
190 fSpecs.put(i, spec);
191 }
192
193 private UndoSpec removeEdit(int offset) {
194 Integer i= new Integer (offset);
195 UndoSpec spec= (UndoSpec) fSpecs.remove(i);
196 return spec;
197 }
198
199 private void ensureListenerInstalled() {
200 if (fBackspaceListener == null) {
201 fBackspaceListener= new BackspaceListener();
202 ITextViewer viewer= fViewer;
203 if (viewer instanceof ITextViewerExtension)
204 ((ITextViewerExtension) viewer).prependVerifyKeyListener(fBackspaceListener);
205 else
206 viewer.getTextWidget().addVerifyKeyListener(fBackspaceListener);
207 }
208 }
209
210 private void ensureListenerRemoved() {
211 if (fBackspaceListener != null) {
212 ITextViewer viewer= fViewer;
213 if (viewer instanceof ITextViewerExtension)
214 ((ITextViewerExtension) viewer).removeVerifyKeyListener(fBackspaceListener);
215 else
216 viewer.getTextWidget().removeVerifyKeyListener(fBackspaceListener);
217 fBackspaceListener= null;
218 }
219 }
220
221 private IDocument getDocument() {
222 return fViewer.getDocument();
223 }
224
225
230 public void install(ITextViewer viewer) {
231 Assert.isLegal(viewer != null);
232
233 fViewer= viewer;
234 fSpecs= new HashMap ();
235 fRunDetector= new TypingRunDetector();
236 fRunDetector.install(viewer);
237 fRunListener= new ITypingRunListener() {
238
239
242 public void typingRunStarted(TypingRun run) {
243 }
244
245
248 public void typingRunEnded(TypingRun run, ChangeType reason) {
249 if (reason == TypingRun.SELECTION)
250 fSpecs.clear();
251 else
252 prune();
253 }
254 };
255 fRunDetector.addTypingRunListener(fRunListener);
256 }
257
258 private void prune() {
259 for (Iterator it= fSpecs.values().iterator(); it.hasNext();) {
260 UndoSpec spec= (UndoSpec) it.next();
261 if (--spec.lives < 0)
262 it.remove();
263 }
264 }
265
266
270 public void uninstall() {
271 if (fViewer != null) {
272 fRunDetector.removeTypingRunListener(fRunListener);
273 fRunDetector.uninstall();
274 fRunDetector= null;
275 ensureListenerRemoved();
276 fViewer= null;
277 }
278 }
279 }
280 |
Popular Tags |
Java API By Example, From Geeks To Geeks.