1 | // Copyright 2012 Georg-August-Universität Göttingen, Germany |
---|
2 | // |
---|
3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
---|
4 | // you may not use this file except in compliance with the License. |
---|
5 | // You may obtain a copy of the License at |
---|
6 | // |
---|
7 | // http://www.apache.org/licenses/LICENSE-2.0 |
---|
8 | // |
---|
9 | // Unless required by applicable law or agreed to in writing, software |
---|
10 | // distributed under the License is distributed on an "AS IS" BASIS, |
---|
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
---|
12 | // See the License for the specific language governing permissions and |
---|
13 | // limitations under the License. |
---|
14 | |
---|
15 | package de.ugoe.cs.autoquest.usageprofiles; |
---|
16 | |
---|
17 | import java.io.Serializable; |
---|
18 | import java.util.ArrayList; |
---|
19 | import java.util.Arrays; |
---|
20 | import java.util.Collection; |
---|
21 | import java.util.HashMap; |
---|
22 | import java.util.Iterator; |
---|
23 | import java.util.LinkedList; |
---|
24 | import java.util.List; |
---|
25 | import java.util.Map; |
---|
26 | import java.util.Map.Entry; |
---|
27 | |
---|
28 | /** |
---|
29 | * <p> |
---|
30 | * This class is a data structure for holding symbols which is more efficient than a simple list. |
---|
31 | * This data structure can be used with a comparator to adapt the effective list behavior and to |
---|
32 | * define the equals strategy for comparing objects. After a certain size ({@link #MAX_LIST_SIZE}), |
---|
33 | * the symbol map creates a symbol index consisting of buckets. This allows searching for symbols |
---|
34 | * in a more efficient order as the search can start in the most appropriate of the internal |
---|
35 | * buckets. |
---|
36 | * </p> |
---|
37 | * <p> |
---|
38 | * The class is called a map, although it is not. It may contain the same element as separate keys. |
---|
39 | * This implementation is done for performance improvements. If it is required to really assure, |
---|
40 | * that a key exists only once, then each call to the {@link #addSymbol(Object, Object)} method |
---|
41 | * should be done only, if the {@link #containsSymbol(Object)} method for the same symbol returns |
---|
42 | * false. |
---|
43 | * </p> |
---|
44 | * |
---|
45 | * @see SymbolComparator |
---|
46 | * |
---|
47 | * @author Patrick Harms |
---|
48 | */ |
---|
49 | public class SymbolMap<K, V> implements Serializable { |
---|
50 | |
---|
51 | /** |
---|
52 | * <p> |
---|
53 | * default serial version UID |
---|
54 | * </p> |
---|
55 | */ |
---|
56 | private static final long serialVersionUID = 1L; |
---|
57 | |
---|
58 | /** |
---|
59 | * <p> |
---|
60 | * the maximum number of symbols in this map which is still only treated as list instead of |
---|
61 | * using buckets. |
---|
62 | * </p> |
---|
63 | */ |
---|
64 | private static final int MAX_LIST_SIZE = 15; |
---|
65 | |
---|
66 | /** |
---|
67 | * <p> |
---|
68 | * Comparator to be used for comparing the symbols with each other and to determine a bucket |
---|
69 | * search order |
---|
70 | * </p> |
---|
71 | */ |
---|
72 | private SymbolComparator<K> comparator; |
---|
73 | |
---|
74 | /** |
---|
75 | * <p> |
---|
76 | * Internally maintained plain list of symbols and associated values |
---|
77 | * </p> |
---|
78 | */ |
---|
79 | private List<Map.Entry<K, V>> symbolList; |
---|
80 | |
---|
81 | /** |
---|
82 | * <p> |
---|
83 | * If the size of the map exceeds {@link #MAX_LIST_SIZE}, this is the symbol index using buckets |
---|
84 | * for optimizing the search order. |
---|
85 | * </p> |
---|
86 | */ |
---|
87 | private Map<Integer, List<Map.Entry<K, V>>> symbolBuckets; |
---|
88 | |
---|
89 | /** |
---|
90 | * <p> |
---|
91 | * When using buckets, not any symbol may be associated a correct bucket by the used |
---|
92 | * comparator. Therefore, we set a default bucket for all such symbols. This may change |
---|
93 | * if the comparator defines the same bucket for a specific symbol. |
---|
94 | * </p> |
---|
95 | */ |
---|
96 | private int defaultBucket = 0; |
---|
97 | |
---|
98 | /** |
---|
99 | * <p> |
---|
100 | * Instantiates a symbol map with a comparator |
---|
101 | * </p> |
---|
102 | * |
---|
103 | * @param comparator the comparator to use for comparing symbols and for determining bucket |
---|
104 | * search orders |
---|
105 | * |
---|
106 | * @throws IllegalArgumentException if the provided comparator is null |
---|
107 | */ |
---|
108 | public SymbolMap(SymbolComparator<K> comparator) { |
---|
109 | if (comparator == null) { |
---|
110 | throw new IllegalArgumentException("comparator must not be null"); |
---|
111 | } |
---|
112 | |
---|
113 | this.comparator = comparator; |
---|
114 | this.symbolList = new ArrayList<Map.Entry<K, V>>(); |
---|
115 | } |
---|
116 | |
---|
117 | /** |
---|
118 | * <p> |
---|
119 | * Copy constructure |
---|
120 | * </p> |
---|
121 | * |
---|
122 | * @param otherMap the other map to be copied including its comparator |
---|
123 | * |
---|
124 | * @throws IllegalArgumentException if the provided other map is null |
---|
125 | */ |
---|
126 | public SymbolMap(SymbolMap<K, V> otherMap) { |
---|
127 | if (otherMap == null) { |
---|
128 | throw new IllegalArgumentException("otherMap must not be null"); |
---|
129 | } |
---|
130 | |
---|
131 | this.comparator = otherMap.comparator; |
---|
132 | this.symbolList = new ArrayList<Map.Entry<K, V>>(otherMap.symbolList); |
---|
133 | |
---|
134 | if (this.symbolList.size() > MAX_LIST_SIZE) { |
---|
135 | createSymbolBuckets(); |
---|
136 | } |
---|
137 | } |
---|
138 | |
---|
139 | /** |
---|
140 | * <p> |
---|
141 | * Returns the size of the map, i.e. the number of symbol entries |
---|
142 | * </p> |
---|
143 | * |
---|
144 | * @return as described |
---|
145 | */ |
---|
146 | public int size() { |
---|
147 | return symbolList.size(); |
---|
148 | } |
---|
149 | |
---|
150 | /** |
---|
151 | * <p> |
---|
152 | * Returns true if this map is empty, i.e. if {@link #size()} returns 0 |
---|
153 | * </p> |
---|
154 | * |
---|
155 | * @return as described |
---|
156 | */ |
---|
157 | public boolean isEmpty() { |
---|
158 | return symbolList.isEmpty(); |
---|
159 | } |
---|
160 | |
---|
161 | /** |
---|
162 | * <p> |
---|
163 | * Returns true if the provided symbol was stored in this map. |
---|
164 | * </p> |
---|
165 | * |
---|
166 | * @param symbol the symbol to check if it was stored in this map |
---|
167 | * |
---|
168 | * @return as described |
---|
169 | * |
---|
170 | * @throws IllegalArgumentException if the provided symbol is null |
---|
171 | */ |
---|
172 | public boolean containsSymbol(K symbol) { |
---|
173 | if (symbol == null) { |
---|
174 | throw new IllegalArgumentException("symbol must not be null"); |
---|
175 | } |
---|
176 | |
---|
177 | return getEntry(symbol) != null; |
---|
178 | } |
---|
179 | |
---|
180 | /** |
---|
181 | * <p> |
---|
182 | * Returns the value associated to the provided symbol in this map. If there is no value |
---|
183 | * associated to the given symbol or if the symbol is not stored in this map, the method |
---|
184 | * returns null. |
---|
185 | * </p> |
---|
186 | * |
---|
187 | * @param symbol the symbol to return the value for |
---|
188 | * |
---|
189 | * @return as described |
---|
190 | * |
---|
191 | * @throws IllegalArgumentException if the provided symbol is null |
---|
192 | */ |
---|
193 | public V getValue(K symbol) { |
---|
194 | if (symbol == null) { |
---|
195 | throw new IllegalArgumentException("symbol must not be null"); |
---|
196 | } |
---|
197 | |
---|
198 | Map.Entry<K, V> entry = getEntry(symbol); |
---|
199 | |
---|
200 | if (entry != null) { |
---|
201 | return entry.getValue(); |
---|
202 | } |
---|
203 | else { |
---|
204 | return null; |
---|
205 | } |
---|
206 | } |
---|
207 | |
---|
208 | /** |
---|
209 | * <p> |
---|
210 | * Adds a symbol and an associated value to the map. If the value is null, the symbol is added, |
---|
211 | * anyway and {@link #containsSymbol(Object)} will return true for that symbol. Adding the |
---|
212 | * same symbol twice will produce two entries. This is contradictory to typical map |
---|
213 | * implementations. To prevent this, the {@link #containsSymbol(Object)} and |
---|
214 | * {@link #removeSymbol(Object)} methods should be used to ensure map behavior. |
---|
215 | * </p> |
---|
216 | * |
---|
217 | * @param symbol the symbol to add to the map |
---|
218 | * @param value the value to associate to the symbol in this map |
---|
219 | * |
---|
220 | * @return as described |
---|
221 | * |
---|
222 | * @throws IllegalArgumentException if the provided symbol is null |
---|
223 | */ |
---|
224 | public void addSymbol(K symbol, V value) { |
---|
225 | if (symbol == null) { |
---|
226 | throw new IllegalArgumentException("symbol must not be null"); |
---|
227 | } |
---|
228 | |
---|
229 | Map.Entry<K, V> entry = new SymbolMapEntry(symbol, value); |
---|
230 | |
---|
231 | symbolList.add(entry); |
---|
232 | |
---|
233 | if (symbolList.size() > MAX_LIST_SIZE) { |
---|
234 | if (symbolBuckets == null) { |
---|
235 | createSymbolBuckets(); |
---|
236 | } |
---|
237 | else { |
---|
238 | addToSymbolBucket(entry); |
---|
239 | } |
---|
240 | } |
---|
241 | } |
---|
242 | |
---|
243 | /** |
---|
244 | * <p> |
---|
245 | * Removes a symbol and its associated value from the map. If the symbol is stored several |
---|
246 | * times, the first of its occurrences is removed. |
---|
247 | * </p> |
---|
248 | * |
---|
249 | * @param symbol the symbol to be removed from the map |
---|
250 | * |
---|
251 | * @return as described |
---|
252 | * |
---|
253 | * @throws IllegalArgumentException if the provided symbol is null |
---|
254 | */ |
---|
255 | public V removeSymbol(K symbol) { |
---|
256 | if (symbol == null) { |
---|
257 | throw new IllegalArgumentException("symbol must not be null"); |
---|
258 | } |
---|
259 | |
---|
260 | for (int i = 0; i < symbolList.size(); i++) { |
---|
261 | if (comparator.equals(symbolList.get(i).getKey(), symbol)) { |
---|
262 | // found the symbol. Remove it from the list, and if required, also from the map. |
---|
263 | V value = symbolList.remove(i).getValue(); |
---|
264 | |
---|
265 | if (symbolList.size() > MAX_LIST_SIZE) { |
---|
266 | removeFromSymbolBuckets(symbol); |
---|
267 | } |
---|
268 | |
---|
269 | return value; |
---|
270 | } |
---|
271 | } |
---|
272 | |
---|
273 | return null; |
---|
274 | } |
---|
275 | |
---|
276 | /** |
---|
277 | * <p> |
---|
278 | * Returns a collection of all symbols in this map. |
---|
279 | * </p> |
---|
280 | * |
---|
281 | * @return as described |
---|
282 | */ |
---|
283 | public Collection<K> getSymbols() { |
---|
284 | return new ReadOnlyCollectionFacade<K>(symbolList, new SymbolFacade()); |
---|
285 | } |
---|
286 | |
---|
287 | /** |
---|
288 | * <p> |
---|
289 | * Returns a collection of all values associated to symbols in this map. May contain null |
---|
290 | * values, if some of the symbols are mapped to null. The length of the returned collection |
---|
291 | * is in any case the same as the size of the map. |
---|
292 | * </p> |
---|
293 | * |
---|
294 | * @return as described |
---|
295 | */ |
---|
296 | public Collection<V> getValues() { |
---|
297 | return new ReadOnlyCollectionFacade<V>(symbolList, new ValueFacade()); |
---|
298 | } |
---|
299 | |
---|
300 | /** |
---|
301 | * <p> |
---|
302 | * Removes all symbols and associated values from the map. |
---|
303 | * </p> |
---|
304 | */ |
---|
305 | public void clear() { |
---|
306 | symbolList.clear(); |
---|
307 | symbolBuckets = null; |
---|
308 | } |
---|
309 | |
---|
310 | /* (non-Javadoc) |
---|
311 | * @see java.lang.Object#hashCode() |
---|
312 | */ |
---|
313 | @Override |
---|
314 | public int hashCode() { |
---|
315 | return symbolList.size(); |
---|
316 | } |
---|
317 | |
---|
318 | /* (non-Javadoc) |
---|
319 | * @see java.lang.Object#equals(java.lang.Object) |
---|
320 | */ |
---|
321 | @SuppressWarnings("unchecked") |
---|
322 | @Override |
---|
323 | public boolean equals(Object obj) { |
---|
324 | if (this == obj) { |
---|
325 | return true; |
---|
326 | } |
---|
327 | else if (this.getClass().isInstance(obj)) { |
---|
328 | SymbolMap<K, V> other = (SymbolMap<K, V>) obj; |
---|
329 | |
---|
330 | return (symbolList.size() == other.symbolList.size()) && |
---|
331 | (symbolList.containsAll(other.symbolList)); |
---|
332 | } |
---|
333 | else { |
---|
334 | return false; |
---|
335 | } |
---|
336 | } |
---|
337 | |
---|
338 | /** |
---|
339 | * <p> |
---|
340 | * Internally used to create symbol buckets in case the number of stored symbols increased |
---|
341 | * above {@link #MAX_LIST_SIZE}. |
---|
342 | * </p> |
---|
343 | */ |
---|
344 | private void createSymbolBuckets() { |
---|
345 | //System.out.println("creating symbol buckets"); |
---|
346 | symbolBuckets = new HashMap<Integer, List<Map.Entry<K, V>>>(); |
---|
347 | |
---|
348 | for (Map.Entry<K, V> symbol : symbolList) { |
---|
349 | addToSymbolBucket(symbol); |
---|
350 | } |
---|
351 | } |
---|
352 | |
---|
353 | /** |
---|
354 | * <p> |
---|
355 | * Adds a symbol and its value to its corresponding bucket. The corresponding bucket is |
---|
356 | * retrieved from the symbol comparator. It is the first element of the search order returned |
---|
357 | * by the symbol comparator. If the comparator does not define a search order for the symbol |
---|
358 | * the entry is added to the default bucket. If the comparator defines a bucket id |
---|
359 | * identical to the default bucket id, the default bucket id is shifted to another value. |
---|
360 | * </p> |
---|
361 | */ |
---|
362 | private void addToSymbolBucket(Map.Entry<K, V> symbolEntry) { |
---|
363 | int bucketId = defaultBucket; |
---|
364 | int[] bucketSearchOrder = comparator.getBucketSearchOrder(symbolEntry.getKey()); |
---|
365 | |
---|
366 | if ((bucketSearchOrder != null) && (bucketSearchOrder.length > 0)) { |
---|
367 | bucketId = bucketSearchOrder[0]; |
---|
368 | |
---|
369 | if (bucketId == defaultBucket) { |
---|
370 | setNewDefaultBucketId(); |
---|
371 | } |
---|
372 | } |
---|
373 | |
---|
374 | List<Map.Entry<K, V>> list = symbolBuckets.get(bucketId); |
---|
375 | |
---|
376 | if (list == null) { |
---|
377 | list = new LinkedList<Map.Entry<K, V>>(); |
---|
378 | symbolBuckets.put(bucketId, list); |
---|
379 | } |
---|
380 | |
---|
381 | list.add(symbolEntry); |
---|
382 | } |
---|
383 | |
---|
384 | /** |
---|
385 | * <p> |
---|
386 | * Removes the entry for a given symbol from the buckets. It uses the bucket search order |
---|
387 | * defined by the symbol comparator to find the symbol as fast as possible. |
---|
388 | * </p> |
---|
389 | */ |
---|
390 | private Map.Entry<K, V> removeFromSymbolBuckets(K symbol) { |
---|
391 | int bucketId = defaultBucket; |
---|
392 | int[] bucketSearchOrder = comparator.getBucketSearchOrder(symbol); |
---|
393 | |
---|
394 | if ((bucketSearchOrder != null) && (bucketSearchOrder.length > 0)) { |
---|
395 | bucketId = bucketSearchOrder[0]; |
---|
396 | } |
---|
397 | |
---|
398 | List<Map.Entry<K, V>> list = symbolBuckets.get(bucketId); |
---|
399 | Map.Entry<K, V> result = null; |
---|
400 | |
---|
401 | if (list != null) { |
---|
402 | for (int i = 0; i < list.size(); i++) { |
---|
403 | if (comparator.equals(list.get(i).getKey(), symbol)) { |
---|
404 | result = list.remove(i); |
---|
405 | break; |
---|
406 | } |
---|
407 | } |
---|
408 | |
---|
409 | if (list.isEmpty()) { |
---|
410 | symbolBuckets.remove(bucketId); |
---|
411 | } |
---|
412 | } |
---|
413 | |
---|
414 | return result; |
---|
415 | } |
---|
416 | |
---|
417 | /** |
---|
418 | * <p> |
---|
419 | * Updates the default bucket id to a new one |
---|
420 | * </p> |
---|
421 | */ |
---|
422 | private void setNewDefaultBucketId() { |
---|
423 | int oldDefaultBucket = defaultBucket; |
---|
424 | do { |
---|
425 | defaultBucket += 1; |
---|
426 | } |
---|
427 | while (symbolBuckets.containsKey(defaultBucket)); |
---|
428 | |
---|
429 | symbolBuckets.put(defaultBucket, symbolBuckets.get(oldDefaultBucket)); |
---|
430 | } |
---|
431 | |
---|
432 | /** |
---|
433 | * <p> |
---|
434 | * searches for the entry belonging to the given symbol. The method either uses the list if |
---|
435 | * buckets are not used yet, or it uses the buckets and searches them in the order defined |
---|
436 | * by the comparator. If the symbol isn't found and the comparator does not refer all buckets, |
---|
437 | * then also the other buckets are searched for the symbol. |
---|
438 | * </p> |
---|
439 | */ |
---|
440 | private Map.Entry<K, V> getEntry(K symbol) { |
---|
441 | Map.Entry<K, V> entry = null; |
---|
442 | if (symbolBuckets == null) { |
---|
443 | entry = lookup(symbol, symbolList); |
---|
444 | } |
---|
445 | else { |
---|
446 | int[] bucketSearchOrder = comparator.getBucketSearchOrder(symbol); |
---|
447 | for (int bucketId : bucketSearchOrder) { |
---|
448 | List<Map.Entry<K, V>> list = symbolBuckets.get(bucketId); |
---|
449 | if (list != null) { |
---|
450 | entry = lookup(symbol, list); |
---|
451 | if (entry != null) { |
---|
452 | break; |
---|
453 | } |
---|
454 | } |
---|
455 | } |
---|
456 | |
---|
457 | // try to search the other buckets |
---|
458 | if (entry == null) { |
---|
459 | Arrays.sort(bucketSearchOrder); |
---|
460 | for (Map.Entry<Integer, List<Map.Entry<K, V>>> bucket : symbolBuckets.entrySet()) { |
---|
461 | if (Arrays.binarySearch(bucketSearchOrder, bucket.getKey()) < 0) { |
---|
462 | List<Map.Entry<K, V>> list = bucket.getValue(); |
---|
463 | if (list != null) { |
---|
464 | entry = lookup(symbol, list); |
---|
465 | if (entry != null) { |
---|
466 | break; |
---|
467 | } |
---|
468 | } |
---|
469 | } |
---|
470 | } |
---|
471 | } |
---|
472 | } |
---|
473 | |
---|
474 | return entry; |
---|
475 | } |
---|
476 | |
---|
477 | /** |
---|
478 | * <p> |
---|
479 | * Convenience method to look up a symbol in a list of entries using the comparator. |
---|
480 | * </p> |
---|
481 | */ |
---|
482 | private Map.Entry<K, V> lookup(K symbol, List<Map.Entry<K, V>> list) { |
---|
483 | for (Map.Entry<K, V> candidate : list) { |
---|
484 | if (comparator.equals(candidate.getKey(), symbol)) { |
---|
485 | return candidate; |
---|
486 | } |
---|
487 | } |
---|
488 | |
---|
489 | return null; |
---|
490 | } |
---|
491 | |
---|
492 | /** |
---|
493 | * <p> |
---|
494 | * Internally used data structure for storing symbol value pairs |
---|
495 | * </p> |
---|
496 | * |
---|
497 | * @author Patrick Harms |
---|
498 | */ |
---|
499 | private class SymbolMapEntry implements Map.Entry<K, V> { |
---|
500 | |
---|
501 | /** |
---|
502 | * the symbol to map to a value |
---|
503 | */ |
---|
504 | private K symbol; |
---|
505 | |
---|
506 | /** |
---|
507 | * the value associated with the symbol |
---|
508 | */ |
---|
509 | private V value; |
---|
510 | |
---|
511 | /** |
---|
512 | * <p> |
---|
513 | * Simple constructor for initializing the entry with a symbol and its associated value. |
---|
514 | * </p> |
---|
515 | */ |
---|
516 | private SymbolMapEntry(K symbol, V value) { |
---|
517 | super(); |
---|
518 | this.symbol = symbol; |
---|
519 | this.value = value; |
---|
520 | } |
---|
521 | |
---|
522 | /* (non-Javadoc) |
---|
523 | * @see java.util.Map.Entry#getKey() |
---|
524 | */ |
---|
525 | @Override |
---|
526 | public K getKey() { |
---|
527 | return symbol; |
---|
528 | } |
---|
529 | |
---|
530 | /* (non-Javadoc) |
---|
531 | * @see java.util.Map.Entry#getValue() |
---|
532 | */ |
---|
533 | @Override |
---|
534 | public V getValue() { |
---|
535 | return value; |
---|
536 | } |
---|
537 | |
---|
538 | /* (non-Javadoc) |
---|
539 | * @see java.util.Map.Entry#setValue(java.lang.Object) |
---|
540 | */ |
---|
541 | @Override |
---|
542 | public V setValue(V value) { |
---|
543 | V oldValue = this.value; |
---|
544 | this.value = value; |
---|
545 | return oldValue; |
---|
546 | } |
---|
547 | |
---|
548 | /* (non-Javadoc) |
---|
549 | * @see java.lang.Object#hashCode() |
---|
550 | */ |
---|
551 | @Override |
---|
552 | public int hashCode() { |
---|
553 | return symbol.hashCode(); |
---|
554 | } |
---|
555 | |
---|
556 | /* (non-Javadoc) |
---|
557 | * @see java.lang.Object#equals(java.lang.Object) |
---|
558 | */ |
---|
559 | @SuppressWarnings("unchecked") |
---|
560 | @Override |
---|
561 | public boolean equals(Object obj) { |
---|
562 | if (this == obj) { |
---|
563 | return true; |
---|
564 | } |
---|
565 | else if (this.getClass().isInstance(obj)) { |
---|
566 | SymbolMapEntry other = (SymbolMapEntry) obj; |
---|
567 | return (symbol.equals(other.symbol) && |
---|
568 | (value == null ? other.value == null : value.equals(other.value))); |
---|
569 | } |
---|
570 | else { |
---|
571 | return false; |
---|
572 | } |
---|
573 | } |
---|
574 | |
---|
575 | /* (non-Javadoc) |
---|
576 | * @see java.lang.Object#toString() |
---|
577 | */ |
---|
578 | @Override |
---|
579 | public String toString() { |
---|
580 | return symbol + "=" + value; |
---|
581 | } |
---|
582 | |
---|
583 | } |
---|
584 | |
---|
585 | /** |
---|
586 | * <p> |
---|
587 | * Used to create an efficient facade for accessing the internal list of entries either only |
---|
588 | * for the symbols or only for the values. It is a default implementation of the collection |
---|
589 | * interface. The entry facade provided to the constructor decides, if either the list |
---|
590 | * accesses only the symbols or only the values. |
---|
591 | * </p> |
---|
592 | * |
---|
593 | * @author Patrick Harms |
---|
594 | */ |
---|
595 | private class ReadOnlyCollectionFacade<TYPE> implements Collection<TYPE> { |
---|
596 | |
---|
597 | /** |
---|
598 | * the list facaded by this facade |
---|
599 | */ |
---|
600 | private List<Map.Entry<K, V>> list; |
---|
601 | |
---|
602 | /** |
---|
603 | * the facade to be used for the entries |
---|
604 | */ |
---|
605 | private EntryFacade<TYPE> entryFacade; |
---|
606 | |
---|
607 | /** |
---|
608 | * <p> |
---|
609 | * Initializes the facade with the facaded list and the facade to be used for the entries |
---|
610 | * </p> |
---|
611 | */ |
---|
612 | private ReadOnlyCollectionFacade(List<Map.Entry<K, V>> list, EntryFacade<TYPE> entryFacade) |
---|
613 | { |
---|
614 | this.list = list; |
---|
615 | this.entryFacade = entryFacade; |
---|
616 | } |
---|
617 | |
---|
618 | /* (non-Javadoc) |
---|
619 | * @see java.util.Collection#size() |
---|
620 | */ |
---|
621 | @Override |
---|
622 | public int size() { |
---|
623 | return list.size(); |
---|
624 | } |
---|
625 | |
---|
626 | /* (non-Javadoc) |
---|
627 | * @see java.util.Collection#isEmpty() |
---|
628 | */ |
---|
629 | @Override |
---|
630 | public boolean isEmpty() { |
---|
631 | return list.isEmpty(); |
---|
632 | } |
---|
633 | |
---|
634 | /* (non-Javadoc) |
---|
635 | * @see java.util.Collection#contains(java.lang.Object) |
---|
636 | */ |
---|
637 | @Override |
---|
638 | public boolean contains(Object o) { |
---|
639 | if (o == null) { |
---|
640 | for (Map.Entry<K, V> entry : list) { |
---|
641 | if (entryFacade.getFacadedElement(entry) == null) { |
---|
642 | return true; |
---|
643 | } |
---|
644 | } |
---|
645 | } |
---|
646 | else { |
---|
647 | for (Map.Entry<K, V> entry : list) { |
---|
648 | if (o.equals(entryFacade.getFacadedElement(entry))) { |
---|
649 | return true; |
---|
650 | } |
---|
651 | } |
---|
652 | } |
---|
653 | |
---|
654 | return false; |
---|
655 | } |
---|
656 | |
---|
657 | /* (non-Javadoc) |
---|
658 | * @see java.util.Collection#toArray() |
---|
659 | */ |
---|
660 | @Override |
---|
661 | public Object[] toArray() { |
---|
662 | Object[] result = new Object[list.size()]; |
---|
663 | |
---|
664 | for (int i = 0; i < list.size(); i++) { |
---|
665 | result[i] = entryFacade.getFacadedElement(list.get(i)); |
---|
666 | } |
---|
667 | |
---|
668 | return result; |
---|
669 | } |
---|
670 | |
---|
671 | /* (non-Javadoc) |
---|
672 | * @see java.util.Collection#toArray(T[]) |
---|
673 | */ |
---|
674 | @SuppressWarnings("unchecked") |
---|
675 | @Override |
---|
676 | public <T> T[] toArray(T[] a) { |
---|
677 | T[] result = a; |
---|
678 | |
---|
679 | for (int i = 0; i < list.size(); i++) { |
---|
680 | result[i] = (T) entryFacade.getFacadedElement(list.get(i)); |
---|
681 | } |
---|
682 | |
---|
683 | return result; |
---|
684 | } |
---|
685 | |
---|
686 | /* (non-Javadoc) |
---|
687 | * @see java.util.Collection#add(java.lang.Object) |
---|
688 | */ |
---|
689 | @Override |
---|
690 | public boolean add(TYPE e) { |
---|
691 | throw new UnsupportedOperationException("this collection is read only"); |
---|
692 | } |
---|
693 | |
---|
694 | /* (non-Javadoc) |
---|
695 | * @see java.util.Collection#remove(java.lang.Object) |
---|
696 | */ |
---|
697 | @Override |
---|
698 | public boolean remove(Object o) { |
---|
699 | throw new UnsupportedOperationException("this collection is read only"); |
---|
700 | } |
---|
701 | |
---|
702 | /* (non-Javadoc) |
---|
703 | * @see java.util.Collection#containsAll(java.util.Collection) |
---|
704 | */ |
---|
705 | @Override |
---|
706 | public boolean containsAll(Collection<?> c) { |
---|
707 | for (Object candidate : c) { |
---|
708 | if (!contains(candidate)) { |
---|
709 | return false; |
---|
710 | } |
---|
711 | } |
---|
712 | |
---|
713 | return true; |
---|
714 | } |
---|
715 | |
---|
716 | /* (non-Javadoc) |
---|
717 | * @see java.util.Collection#addAll(java.util.Collection) |
---|
718 | */ |
---|
719 | @Override |
---|
720 | public boolean addAll(Collection<? extends TYPE> c) { |
---|
721 | throw new UnsupportedOperationException("this collection is read only"); |
---|
722 | } |
---|
723 | |
---|
724 | /* (non-Javadoc) |
---|
725 | * @see java.util.Collection#removeAll(java.util.Collection) |
---|
726 | */ |
---|
727 | @Override |
---|
728 | public boolean removeAll(Collection<?> c) { |
---|
729 | throw new UnsupportedOperationException("this collection is read only"); |
---|
730 | } |
---|
731 | |
---|
732 | /* (non-Javadoc) |
---|
733 | * @see java.util.Collection#retainAll(java.util.Collection) |
---|
734 | */ |
---|
735 | @Override |
---|
736 | public boolean retainAll(Collection<?> c) { |
---|
737 | throw new UnsupportedOperationException("this collection is read only"); |
---|
738 | } |
---|
739 | |
---|
740 | /* (non-Javadoc) |
---|
741 | * @see java.util.Collection#clear() |
---|
742 | */ |
---|
743 | @Override |
---|
744 | public void clear() { |
---|
745 | throw new UnsupportedOperationException("this collection is read only"); |
---|
746 | } |
---|
747 | |
---|
748 | /* (non-Javadoc) |
---|
749 | * @see java.util.Collection#iterator() |
---|
750 | */ |
---|
751 | @Override |
---|
752 | public Iterator<TYPE> iterator() { |
---|
753 | return new ReadOnlyCollectionIteratorFacade<TYPE>(list.iterator(), entryFacade); |
---|
754 | } |
---|
755 | |
---|
756 | } |
---|
757 | |
---|
758 | /** |
---|
759 | * <p> |
---|
760 | * Implementation of an iterator to facade an iterator on the internal list of symbol entries. |
---|
761 | * </p> |
---|
762 | * |
---|
763 | * @author Patrick Harms |
---|
764 | */ |
---|
765 | private class ReadOnlyCollectionIteratorFacade<TYPE> implements Iterator<TYPE> { |
---|
766 | |
---|
767 | /** |
---|
768 | * the facaded iterator |
---|
769 | */ |
---|
770 | private Iterator<Map.Entry<K, V>> iterator; |
---|
771 | |
---|
772 | /** |
---|
773 | * the facade for the entries provided by the facaded iterator |
---|
774 | */ |
---|
775 | private EntryFacade<TYPE> entryFacade; |
---|
776 | |
---|
777 | /** |
---|
778 | * <p> |
---|
779 | * initialized this facade with the facaded iterator and the entry facade to be used for |
---|
780 | * the entries. |
---|
781 | * </p> |
---|
782 | */ |
---|
783 | private ReadOnlyCollectionIteratorFacade(Iterator<Map.Entry<K, V>> iterator, |
---|
784 | EntryFacade<TYPE> entryFacade) |
---|
785 | { |
---|
786 | this.iterator = iterator; |
---|
787 | this.entryFacade = entryFacade; |
---|
788 | } |
---|
789 | |
---|
790 | /* (non-Javadoc) |
---|
791 | * @see java.util.Iterator#hasNext() |
---|
792 | */ |
---|
793 | @Override |
---|
794 | public boolean hasNext() { |
---|
795 | return iterator.hasNext(); |
---|
796 | } |
---|
797 | |
---|
798 | /* (non-Javadoc) |
---|
799 | * @see java.util.Iterator#next() |
---|
800 | */ |
---|
801 | @Override |
---|
802 | public TYPE next() { |
---|
803 | return entryFacade.getFacadedElement(iterator.next()); |
---|
804 | } |
---|
805 | |
---|
806 | /* (non-Javadoc) |
---|
807 | * @see java.util.Iterator#remove() |
---|
808 | */ |
---|
809 | @Override |
---|
810 | public void remove() { |
---|
811 | throw new UnsupportedOperationException("this iterator is read only"); |
---|
812 | } |
---|
813 | |
---|
814 | } |
---|
815 | |
---|
816 | /** |
---|
817 | * <p> |
---|
818 | * Used to facade symbol entries and to return only this part of an entry, that is relevant. |
---|
819 | * </p> |
---|
820 | * |
---|
821 | * @author Patrick Harms |
---|
822 | */ |
---|
823 | private abstract class EntryFacade<T> { |
---|
824 | |
---|
825 | /** |
---|
826 | * <p> |
---|
827 | * Returns only the part of an entry that is relevant or required. |
---|
828 | * </p> |
---|
829 | * |
---|
830 | * @param entry of which the part shall be returned |
---|
831 | * |
---|
832 | * @return the part of the entry to be returned |
---|
833 | */ |
---|
834 | protected abstract T getFacadedElement(Entry<K, V> entry); |
---|
835 | |
---|
836 | } |
---|
837 | |
---|
838 | /** |
---|
839 | * <p> |
---|
840 | * Implementation of the entry facade returning the entries key, i.e. the symbol. |
---|
841 | * </p> |
---|
842 | * |
---|
843 | * @author Patrick Harms |
---|
844 | */ |
---|
845 | private class SymbolFacade extends EntryFacade<K> { |
---|
846 | |
---|
847 | /* (non-Javadoc) |
---|
848 | * @see ReadOnlyCollectionIteratorFacade#getFacadedElement(Entry) |
---|
849 | */ |
---|
850 | @Override |
---|
851 | protected K getFacadedElement(Entry<K, V> entry) { |
---|
852 | return entry.getKey(); |
---|
853 | } |
---|
854 | } |
---|
855 | |
---|
856 | /** |
---|
857 | * <p> |
---|
858 | * Implementation of the entry facade returning the entries value, i.e. the value associated to |
---|
859 | * the symbol. |
---|
860 | * </p> |
---|
861 | * |
---|
862 | * @author Patrick Harms |
---|
863 | */ |
---|
864 | private class ValueFacade extends EntryFacade<V> { |
---|
865 | |
---|
866 | /* (non-Javadoc) |
---|
867 | * @see ReadOnlyCollectionIteratorFacade#getFacadedElement(Entry) |
---|
868 | */ |
---|
869 | @Override |
---|
870 | protected V getFacadedElement(Entry<K, V> entry) { |
---|
871 | return entry.getValue(); |
---|
872 | } |
---|
873 | } |
---|
874 | |
---|
875 | } |
---|