KeyStroke


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 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   *******************************************************************************/
11  
12  package org.eclipse.ui.keys;
13  
14  import java.util.Arrays  ;
15  import java.util.Collections  ;
16  import java.util.Set  ;
17  import java.util.SortedSet  ;
18  import java.util.StringTokenizer  ;
19  import java.util.TreeSet  ;
20  
21  import org.eclipse.ui.internal.util.Util;
22  
23  /**
24   * <p>
25   * A <code>KeyStroke</code> is defined as an optional set of modifier keys
26   * followed optionally by a natural key. A <code>KeyStroke</code> is said to
27   * be complete if it contains a natural key. A natural key is any Unicode
28   * character (e.g., "backspace", etc.), any character belonging to a natural
29   * language (e.g., "A", "1", "[", etc.), or any special control character
30   * specific to computers (e.g., "F10", "PageUp", etc.).
31   * </p>
32   * <p>
33   * All <code>KeyStroke</code> objects have a formal string representation
34   * available via the <code>toString()</code> method. There are a number of
35   * methods to get instances of <code>KeyStroke</code> objects, including one
36   * which can parse this formal string representation.
37   * </p>
38   * <p>
39   * All <code>KeyStroke</code> objects, via the <code>format()</code> method,
40   * provide a version of their formal string representation translated by
41   * platform and locale, suitable for display to a user.
42   * </p>
43   * <p>
44   * <code>KeyStroke</code> objects are immutable. Clients are not permitted to
45   * extend this class.
46   * </p>
47   * 
48   * @deprecated Please use org.eclipse.jface.bindings.keys.KeyStroke
49   * @since 3.0
50   * @see org.eclipse.ui.keys.ModifierKey
51   * @see org.eclipse.ui.keys.NaturalKey
52   */
53  public final class KeyStroke implements Comparable   {
54  
55      /**
56       * The delimiter between multiple keys in a single key strokes -- expressed
57       * in the formal key stroke grammar. This is not to be displayed to the
58       * user. It is only intended as an internal representation.
59       */
60      public final static String   KEY_DELIMITER = "\u002B"; //$NON-NLS-1$
61  
62      /**
63       * An internal constant used only in this object's hash code algorithm.
64       */
65      private final static int HASH_FACTOR = 89;
66  
67      /**
68       * An internal constant used only in this object's hash code algorithm.
69       */
70      private final static int HASH_INITIAL = KeyStroke.class.getName()
71              .hashCode();
72  
73      /**
74       * The set of delimiters for <code>Key</code> objects allowed during
75       * parsing of the formal string representation.
76       */
77      public final static String   KEY_DELIMITERS = KEY_DELIMITER;
78  
79      /**
80       * Gets an instance of <code>KeyStroke</code> given a single modifier key
81       * and a natural key.
82       * 
83       * @param modifierKey
84       *            a modifier key. Must not be <code>null</code>.
85       * @param naturalKey
86       *            the natural key. May be <code>null</code>.
87       * @return a key stroke. Guaranteed not to be <code>null</code>.
88       */
89      public static KeyStroke getInstance(ModifierKey modifierKey,
90              NaturalKey naturalKey) {
91          if (modifierKey == null) {
92              throw new NullPointerException  ();
93          }
94  
95          return new KeyStroke(
96                  new TreeSet  (Collections.singletonList(modifierKey)), naturalKey);
97      }
98  
99      /**
100      * Gets an instance of <code>KeyStroke</code> given an array of modifier
101      * keys and a natural key.
102      * 
103      * @param modifierKeys
104      *            the array of modifier keys. This array may be empty, but it
105      *            must not be <code>null</code>. If this array is not empty,
106      *            it must not contain <code>null</code> elements.
107      * @param naturalKey
108      *            the natural key. May be <code>null</code>.
109      * @return a key stroke. Guaranteed not to be <code>null</code>.
110      */
111     public static KeyStroke getInstance(ModifierKey[] modifierKeys,
112             NaturalKey naturalKey) {
113         Util.assertInstance(modifierKeys, ModifierKey.class);
114         return new KeyStroke(new TreeSet  (Arrays.asList(modifierKeys)),
115                 naturalKey);
116     }
117 
118     /**
119      * Gets an instance of <code>KeyStroke</code> given a natural key.
120      * 
121      * @param naturalKey
122      *            the natural key. May be <code>null</code>.
123      * @return a key stroke. This key stroke will have no modifier keys.
124      *         Guaranteed not to be <code>null</code>.
125      */
126     public static KeyStroke getInstance(NaturalKey naturalKey) {
127         return new KeyStroke(Util.EMPTY_SORTED_SET, naturalKey);
128     }
129 
130     /**
131      * Gets an instance of <code>KeyStroke</code> given a set of modifier
132      * keys and a natural key.
133      * 
134      * @param modifierKeys
135      *            the set of modifier keys. This set may be empty, but it must
136      *            not be <code>null</code>. If this set is not empty, it
137      *            must only contain instances of <code>ModifierKey</code>.
138      * @param naturalKey
139      *            the natural key. May be <code>null</code>.
140      * @return a key stroke. Guaranteed not to be <code>null</code>.
141      */
142     public static KeyStroke getInstance(SortedSet   modifierKeys,
143             NaturalKey naturalKey) {
144         return new KeyStroke(modifierKeys, naturalKey);
145     }
146 
147     /**
148      * Gets an instance of <code>KeyStroke</code> by parsing a given a formal
149      * string representation.
150      * 
151      * @param string
152      *            the formal string representation to parse.
153      * @return a key stroke. Guaranteed not to be <code>null</code>.
154      * @throws ParseException
155      *             if the given formal string representation could not be
156      *             parsed to a valid key stroke.
157      */
158     public static KeyStroke getInstance(String   string) throws ParseException {
159         if (string == null) {
160             throw new NullPointerException  ();
161         }
162 
163         SortedSet   modifierKeys = new TreeSet  ();
164         NaturalKey naturalKey = null;
165         StringTokenizer   stringTokenizer = new StringTokenizer  (string,
166                 KEY_DELIMITERS, true);
167         int i = 0;
168 
169         while (stringTokenizer.hasMoreTokens()) {
170             String   token = stringTokenizer.nextToken();
171 
172             if (i % 2 == 0) {
173                 if (stringTokenizer.hasMoreTokens()) {
174                     token = token.toUpperCase();
175                     ModifierKey modifierKey = (ModifierKey) ModifierKey.modifierKeysByName
176                             .get(token);
177 
178                     if (modifierKey == null || !modifierKeys.add(modifierKey)) {
179                         throw new ParseException(
180                                 "Cannot create key stroke with duplicate or non-existent modifier key: " //$NON-NLS-1$
181                                         + token);
182                     }
183                 } else if (token.length() == 1) {
184                     naturalKey = CharacterKey.getInstance(token.charAt(0));
185                     break;
186                 } else {
187                     token = token.toUpperCase();
188                     naturalKey = (NaturalKey) CharacterKey.characterKeysByName
189                             .get(token);
190 
191                     if (naturalKey == null) {
192                         naturalKey = (NaturalKey) SpecialKey.specialKeysByName
193                                 .get(token);
194                     }
195 
196                     if (naturalKey == null) {
197                         throw new ParseException(
198                                 "Cannot create key stroke with invalid natural key: " //$NON-NLS-1$
199                                         + token);
200                     }
201                 }
202             }
203 
204             i++;
205         }
206 
207         try {
208             return new KeyStroke(modifierKeys, naturalKey);
209         } catch (Throwable   t) {
210             throw new ParseException("Cannot create key stroke with " //$NON-NLS-1$
211                     + modifierKeys + " and " + naturalKey); //$NON-NLS-1$
212         }
213     }
214 
215     /**
216      * The cached hash code for this object. Because <code>KeyStroke</code>
217      * objects are immutable, their hash codes need only to be computed once.
218      * After the first call to <code>hashCode()</code>, the computed value
219      * is cached here for all subsequent calls.
220      */
221     private transient int hashCode;
222 
223     /**
224      * A flag to determine if the <code>hashCode</code> field has already
225      * been computed.
226      */
227     private transient boolean hashCodeComputed;
228 
229     /**
230      * The set of modifier keys for this key stroke.
231      */
232     private SortedSet   modifierKeys;
233 
234     /**
235      * The set of modifier keys for this key stroke in the form of an array.
236      * Used internally by <code>int compareTo(Object)</code>.
237      */
238     private transient ModifierKey[] modifierKeysAsArray;
239 
240     /**
241      * The natural key for this key stroke.
242      */
243     private NaturalKey naturalKey;
244 
245     /**
246      * Constructs an instance of <code>KeyStroke</code> given a set of
247      * modifier keys and a natural key.
248      * 
249      * @param modifierKeys
250      *            the set of modifier keys. This set may be empty, but it must
251      *            not be <code>null</code>. If this set is not empty, it
252      *            must only contain instances of <code>ModifierKey</code>.
253      * @param naturalKey
254      *            the natural key. May be <code>null</code>.
255      */
256     private KeyStroke(SortedSet   modifierKeys, NaturalKey naturalKey) {
257         this.modifierKeys = Util.safeCopy(modifierKeys, ModifierKey.class);
258         this.naturalKey = naturalKey;
259         this.modifierKeysAsArray = (ModifierKey[]) this.modifierKeys
260                 .toArray(new ModifierKey[this.modifierKeys.size()]);
261     }
262 
263     /**
264      * @see java.lang.Comparable#compareTo(java.lang.Object)
265      */
266     public int compareTo(Object   object) {
267         KeyStroke castedObject = (KeyStroke) object;
268         int compareTo = Util.compare(modifierKeysAsArray,
269                 castedObject.modifierKeysAsArray);
270 
271         if (compareTo == 0) {
272             compareTo = Util.compare(naturalKey, castedObject.naturalKey);
273         }
274 
275         return compareTo;
276     }
277 
278     /**
279      * @see java.lang.Object#equals(java.lang.Object)
280      */
281     public boolean equals(Object   object) {
282         if (!(object instanceof KeyStroke)) {
283             return false;
284         }
285 
286         KeyStroke castedObject = (KeyStroke) object;
287         
288         if (!modifierKeys.equals(castedObject.modifierKeys)) {
289             return false;
290         }
291         return Util.equals(naturalKey, castedObject.naturalKey);
292     }
293 
294     /**
295      * Formats this key stroke into the current default look.
296      * 
297      * @return A string representation for this key stroke using the default
298      *         look; never <code>null</code>.
299      */
300     public String   format() {
301         return KeyFormatterFactory.getDefault().format(this);
302     }
303 
304     /**
305      * Returns the set of modifier keys for this key stroke.
306      * 
307      * @return the set of modifier keys. This set may be empty, but is
308      *         guaranteed not to be <code>null</code>. If this set is not
309      *         empty, it is guaranteed to only contain instances of <code>ModifierKey</code>.
310      */
311     public Set   getModifierKeys() {
312         return Collections.unmodifiableSet(modifierKeys);
313     }
314 
315     /**
316      * Returns the natural key for this key stroke.
317      * 
318      * @return the natural key. May be <code>null</code>.
319      */
320     public NaturalKey getNaturalKey() {
321         return naturalKey;
322     }
323 
324     /**
325      * @see java.lang.Object#hashCode()
326      */
327     public int hashCode() {
328         if (!hashCodeComputed) {
329             hashCode = HASH_INITIAL;
330             hashCode = hashCode * HASH_FACTOR + modifierKeys.hashCode();
331             hashCode = hashCode * HASH_FACTOR + Util.hashCode(naturalKey);
332             hashCodeComputed = true;
333         }
334 
335         return hashCode;
336     }
337 
338     /**
339      * Returns whether or not this key stroke is complete. Key strokes are
340      * complete iff they have a natural key which is not <code>null</code>.
341      * 
342      * @return <code>true</code>, iff the key stroke is complete.
343      */
344     public boolean isComplete() {
345         return naturalKey != null;
346     }
347 
348     /**
349      * Returns the formal string representation for this key stroke.
350      * 
351      * @return The formal string representation for this key stroke. Guaranteed
352      *         not to be <code>null</code>.
353      * @see java.lang.Object#toString()
354      */
355     public String   toString() {
356         return KeyFormatterFactory.getFormalKeyFormatter().format(this);
357     }
358 }
359
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