93 * @return the number of elements in this set (its cardinality)
94 */
95 int size();
96
97 /**
98 * Returns <tt>true</tt> if this set contains no elements.
99 *
100 * @return <tt>true</tt> if this set contains no elements
101 */
102 boolean isEmpty();
103
104 /**
105 * Returns <tt>true</tt> if this set contains the specified element.
106 * More formally, returns <tt>true</tt> if and only if this set
107 * contains an element <tt>e</tt> such that
108 * <tt>(o==null ? e==null : o.equals(e))</tt>.
109 *
110 * @param o element whose presence in this set is to be tested
111 * @return <tt>true</tt> if this set contains the specified element
112 * @throws ClassCastException if the type of the specified element
113 * is incompatible with this set (optional)
114 * @throws NullPointerException if the specified element is null and this
115 * set does not permit null elements (optional)
116 */
117 boolean contains(Object o);
118
119 /**
120 * Returns an iterator over the elements in this set. The elements are
121 * returned in no particular order (unless this set is an instance of some
122 * class that provides a guarantee).
123 *
124 * @return an iterator over the elements in this set
125 */
126 Iterator<E> iterator();
127
128 /**
129 * Returns an array containing all of the elements in this set.
130 * If this set makes any guarantees as to what order its elements
131 * are returned by its iterator, this method must return the
132 * elements in the same order.
133 *
134 * <p>The returned array will be "safe" in that no references to it
135 * are maintained by this set. (In other words, this method must
219 * set does not permit null elements
220 * @throws IllegalArgumentException if some property of the specified element
221 * prevents it from being added to this set
222 */
223 boolean add(E e);
224
225
226 /**
227 * Removes the specified element from this set if it is present
228 * (optional operation). More formally, removes an element <tt>e</tt>
229 * such that
230 * <tt>(o==null ? e==null : o.equals(e))</tt>, if
231 * this set contains such an element. Returns <tt>true</tt> if this set
232 * contained the element (or equivalently, if this set changed as a
233 * result of the call). (This set will not contain the element once the
234 * call returns.)
235 *
236 * @param o object to be removed from this set, if present
237 * @return <tt>true</tt> if this set contained the specified element
238 * @throws ClassCastException if the type of the specified element
239 * is incompatible with this set (optional)
240 * @throws NullPointerException if the specified element is null and this
241 * set does not permit null elements (optional)
242 * @throws UnsupportedOperationException if the <tt>remove</tt> operation
243 * is not supported by this set
244 */
245 boolean remove(Object o);
246
247
248 // Bulk Operations
249
250 /**
251 * Returns <tt>true</tt> if this set contains all of the elements of the
252 * specified collection. If the specified collection is also a set, this
253 * method returns <tt>true</tt> if it is a <i>subset</i> of this set.
254 *
255 * @param c collection to be checked for containment in this set
256 * @return <tt>true</tt> if this set contains all of the elements of the
257 * specified collection
258 * @throws ClassCastException if the types of one or more elements
259 * in the specified collection are incompatible with this
260 * set (optional)
261 * @throws NullPointerException if the specified collection contains one
262 * or more null elements and this set does not permit null
263 * elements (optional), or if the specified collection is null
264 * @see #contains(Object)
265 */
266 boolean containsAll(Collection<?> c);
267
268 /**
269 * Adds all of the elements in the specified collection to this set if
270 * they're not already present (optional operation). If the specified
271 * collection is also a set, the <tt>addAll</tt> operation effectively
272 * modifies this set so that its value is the <i>union</i> of the two
273 * sets. The behavior of this operation is undefined if the specified
274 * collection is modified while the operation is in progress.
275 *
276 * @param c collection containing elements to be added to this set
277 * @return <tt>true</tt> if this set changed as a result of the call
278 *
279 * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
280 * is not supported by this set
281 * @throws ClassCastException if the class of an element of the
282 * specified collection prevents it from being added to this set
283 * @throws NullPointerException if the specified collection contains one
285 * elements, or if the specified collection is null
286 * @throws IllegalArgumentException if some property of an element of the
287 * specified collection prevents it from being added to this set
288 * @see #add(Object)
289 */
290 boolean addAll(Collection<? extends E> c);
291
292 /**
293 * Retains only the elements in this set that are contained in the
294 * specified collection (optional operation). In other words, removes
295 * from this set all of its elements that are not contained in the
296 * specified collection. If the specified collection is also a set, this
297 * operation effectively modifies this set so that its value is the
298 * <i>intersection</i> of the two sets.
299 *
300 * @param c collection containing elements to be retained in this set
301 * @return <tt>true</tt> if this set changed as a result of the call
302 * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
303 * is not supported by this set
304 * @throws ClassCastException if the class of an element of this set
305 * is incompatible with the specified collection (optional)
306 * @throws NullPointerException if this set contains a null element and the
307 * specified collection does not permit null elements (optional),
308 * or if the specified collection is null
309 * @see #remove(Object)
310 */
311 boolean retainAll(Collection<?> c);
312
313 /**
314 * Removes from this set all of its elements that are contained in the
315 * specified collection (optional operation). If the specified
316 * collection is also a set, this operation effectively modifies this
317 * set so that its value is the <i>asymmetric set difference</i> of
318 * the two sets.
319 *
320 * @param c collection containing elements to be removed from this set
321 * @return <tt>true</tt> if this set changed as a result of the call
322 * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
323 * is not supported by this set
324 * @throws ClassCastException if the class of an element of this set
325 * is incompatible with the specified collection (optional)
326 * @throws NullPointerException if this set contains a null element and the
327 * specified collection does not permit null elements (optional),
328 * or if the specified collection is null
329 * @see #remove(Object)
330 * @see #contains(Object)
331 */
332 boolean removeAll(Collection<?> c);
333
334 /**
335 * Removes all of the elements from this set (optional operation).
336 * The set will be empty after this call returns.
337 *
338 * @throws UnsupportedOperationException if the <tt>clear</tt> method
339 * is not supported by this set
340 */
341 void clear();
342
343
344 // Comparison and hashing
345
346 /**
347 * Compares the specified object with this set for equality. Returns
|
93 * @return the number of elements in this set (its cardinality)
94 */
95 int size();
96
97 /**
98 * Returns <tt>true</tt> if this set contains no elements.
99 *
100 * @return <tt>true</tt> if this set contains no elements
101 */
102 boolean isEmpty();
103
104 /**
105 * Returns <tt>true</tt> if this set contains the specified element.
106 * More formally, returns <tt>true</tt> if and only if this set
107 * contains an element <tt>e</tt> such that
108 * <tt>(o==null ? e==null : o.equals(e))</tt>.
109 *
110 * @param o element whose presence in this set is to be tested
111 * @return <tt>true</tt> if this set contains the specified element
112 * @throws ClassCastException if the type of the specified element
113 * is incompatible with this set
114 * (<a href="Collection.html#optional-restrictions">optional</a>)
115 * @throws NullPointerException if the specified element is null and this
116 * set does not permit null elements
117 * (<a href="Collection.html#optional-restrictions">optional</a>)
118 */
119 boolean contains(Object o);
120
121 /**
122 * Returns an iterator over the elements in this set. The elements are
123 * returned in no particular order (unless this set is an instance of some
124 * class that provides a guarantee).
125 *
126 * @return an iterator over the elements in this set
127 */
128 Iterator<E> iterator();
129
130 /**
131 * Returns an array containing all of the elements in this set.
132 * If this set makes any guarantees as to what order its elements
133 * are returned by its iterator, this method must return the
134 * elements in the same order.
135 *
136 * <p>The returned array will be "safe" in that no references to it
137 * are maintained by this set. (In other words, this method must
221 * set does not permit null elements
222 * @throws IllegalArgumentException if some property of the specified element
223 * prevents it from being added to this set
224 */
225 boolean add(E e);
226
227
228 /**
229 * Removes the specified element from this set if it is present
230 * (optional operation). More formally, removes an element <tt>e</tt>
231 * such that
232 * <tt>(o==null ? e==null : o.equals(e))</tt>, if
233 * this set contains such an element. Returns <tt>true</tt> if this set
234 * contained the element (or equivalently, if this set changed as a
235 * result of the call). (This set will not contain the element once the
236 * call returns.)
237 *
238 * @param o object to be removed from this set, if present
239 * @return <tt>true</tt> if this set contained the specified element
240 * @throws ClassCastException if the type of the specified element
241 * is incompatible with this set
242 * (<a href="Collection.html#optional-restrictions">optional</a>)
243 * @throws NullPointerException if the specified element is null and this
244 * set does not permit null elements
245 * (<a href="Collection.html#optional-restrictions">optional</a>)
246 * @throws UnsupportedOperationException if the <tt>remove</tt> operation
247 * is not supported by this set
248 */
249 boolean remove(Object o);
250
251
252 // Bulk Operations
253
254 /**
255 * Returns <tt>true</tt> if this set contains all of the elements of the
256 * specified collection. If the specified collection is also a set, this
257 * method returns <tt>true</tt> if it is a <i>subset</i> of this set.
258 *
259 * @param c collection to be checked for containment in this set
260 * @return <tt>true</tt> if this set contains all of the elements of the
261 * specified collection
262 * @throws ClassCastException if the types of one or more elements
263 * in the specified collection are incompatible with this
264 * set
265 * (<a href="Collection.html#optional-restrictions">optional</a>)
266 * @throws NullPointerException if the specified collection contains one
267 * or more null elements and this set does not permit null
268 * elements
269 * (<a href="Collection.html#optional-restrictions">optional</a>),
270 * or if the specified collection is null
271 * @see #contains(Object)
272 */
273 boolean containsAll(Collection<?> c);
274
275 /**
276 * Adds all of the elements in the specified collection to this set if
277 * they're not already present (optional operation). If the specified
278 * collection is also a set, the <tt>addAll</tt> operation effectively
279 * modifies this set so that its value is the <i>union</i> of the two
280 * sets. The behavior of this operation is undefined if the specified
281 * collection is modified while the operation is in progress.
282 *
283 * @param c collection containing elements to be added to this set
284 * @return <tt>true</tt> if this set changed as a result of the call
285 *
286 * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
287 * is not supported by this set
288 * @throws ClassCastException if the class of an element of the
289 * specified collection prevents it from being added to this set
290 * @throws NullPointerException if the specified collection contains one
292 * elements, or if the specified collection is null
293 * @throws IllegalArgumentException if some property of an element of the
294 * specified collection prevents it from being added to this set
295 * @see #add(Object)
296 */
297 boolean addAll(Collection<? extends E> c);
298
299 /**
300 * Retains only the elements in this set that are contained in the
301 * specified collection (optional operation). In other words, removes
302 * from this set all of its elements that are not contained in the
303 * specified collection. If the specified collection is also a set, this
304 * operation effectively modifies this set so that its value is the
305 * <i>intersection</i> of the two sets.
306 *
307 * @param c collection containing elements to be retained in this set
308 * @return <tt>true</tt> if this set changed as a result of the call
309 * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
310 * is not supported by this set
311 * @throws ClassCastException if the class of an element of this set
312 * is incompatible with the specified collection
313 * (<a href="Collection.html#optional-restrictions">optional</a>)
314 * @throws NullPointerException if this set contains a null element and the
315 * specified collection does not permit null elements
316 * (<a href="Collection.html#optional-restrictions">optional</a>),
317 * or if the specified collection is null
318 * @see #remove(Object)
319 */
320 boolean retainAll(Collection<?> c);
321
322 /**
323 * Removes from this set all of its elements that are contained in the
324 * specified collection (optional operation). If the specified
325 * collection is also a set, this operation effectively modifies this
326 * set so that its value is the <i>asymmetric set difference</i> of
327 * the two sets.
328 *
329 * @param c collection containing elements to be removed from this set
330 * @return <tt>true</tt> if this set changed as a result of the call
331 * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
332 * is not supported by this set
333 * @throws ClassCastException if the class of an element of this set
334 * is incompatible with the specified collection
335 * (<a href="Collection.html#optional-restrictions">optional</a>)
336 * @throws NullPointerException if this set contains a null element and the
337 * specified collection does not permit null elements
338 * (<a href="Collection.html#optional-restrictions">optional</a>),
339 * or if the specified collection is null
340 * @see #remove(Object)
341 * @see #contains(Object)
342 */
343 boolean removeAll(Collection<?> c);
344
345 /**
346 * Removes all of the elements from this set (optional operation).
347 * The set will be empty after this call returns.
348 *
349 * @throws UnsupportedOperationException if the <tt>clear</tt> method
350 * is not supported by this set
351 */
352 void clear();
353
354
355 // Comparison and hashing
356
357 /**
358 * Compares the specified object with this set for equality. Returns
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