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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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1+/*
2+ * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
3+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4+ *
5+ * This code is free software; you can redistribute it and/or modify it
6+ * under the terms of the GNU General Public License version 2 only, as
7+ * published by the Free Software Foundation. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
9+ * by Oracle in the LICENSE file that accompanied this code.
10+ *
11+ * This code is distributed in the hope that it will be useful, but WITHOUT
12+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14+ * version 2 for more details (a copy is included in the LICENSE file that
15+ * accompanied this code).
16+ *
17+ * You should have received a copy of the GNU General Public License version
18+ * 2 along with this work; if not, write to the Free Software Foundation,
19+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20+ *
21+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22+ * or visit www.oracle.com if you need additional information or have any
23+ * questions.
24+ */
25+
26+package java.util;
27+
28+/**
29+ * A collection that contains no duplicate elements. More formally, sets
30+ * contain no pair of elements <code>e1</code> and <code>e2</code> such that
31+ * <code>e1.equals(e2)</code>, and at most one null element. As implied by
32+ * its name, this interface models the mathematical <i>set</i> abstraction.
33+ *
34+ * <p>The <tt>Set</tt> interface places additional stipulations, beyond those
35+ * inherited from the <tt>Collection</tt> interface, on the contracts of all
36+ * constructors and on the contracts of the <tt>add</tt>, <tt>equals</tt> and
37+ * <tt>hashCode</tt> methods. Declarations for other inherited methods are
38+ * also included here for convenience. (The specifications accompanying these
39+ * declarations have been tailored to the <tt>Set</tt> interface, but they do
40+ * not contain any additional stipulations.)
41+ *
42+ * <p>The additional stipulation on constructors is, not surprisingly,
43+ * that all constructors must create a set that contains no duplicate elements
44+ * (as defined above).
45+ *
46+ * <p>Note: Great care must be exercised if mutable objects are used as set
47+ * elements. The behavior of a set is not specified if the value of an object
48+ * is changed in a manner that affects <tt>equals</tt> comparisons while the
49+ * object is an element in the set. A special case of this prohibition is
50+ * that it is not permissible for a set to contain itself as an element.
51+ *
52+ * <p>Some set implementations have restrictions on the elements that
53+ * they may contain. For example, some implementations prohibit null elements,
54+ * and some have restrictions on the types of their elements. Attempting to
55+ * add an ineligible element throws an unchecked exception, typically
56+ * <tt>NullPointerException</tt> or <tt>ClassCastException</tt>. Attempting
57+ * to query the presence of an ineligible element may throw an exception,
58+ * or it may simply return false; some implementations will exhibit the former
59+ * behavior and some will exhibit the latter. More generally, attempting an
60+ * operation on an ineligible element whose completion would not result in
61+ * the insertion of an ineligible element into the set may throw an
62+ * exception or it may succeed, at the option of the implementation.
63+ * Such exceptions are marked as "optional" in the specification for this
64+ * interface.
65+ *
66+ * <p>This interface is a member of the
67+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
68+ * Java Collections Framework</a>.
69+ *
70+ * @param <E> the type of elements maintained by this set
71+ *
72+ * @author Josh Bloch
73+ * @author Neal Gafter
74+ * @see Collection
75+ * @see List
76+ * @see SortedSet
77+ * @see HashSet
78+ * @see TreeSet
79+ * @see AbstractSet
80+ * @see Collections#singleton(java.lang.Object)
81+ * @see Collections#EMPTY_SET
82+ * @since 1.2
83+ */
84+
85+public interface Set<E> extends Collection<E> {
86+ // Query Operations
87+
88+ /**
89+ * Returns the number of elements in this set (its cardinality). If this
90+ * set contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
91+ * <tt>Integer.MAX_VALUE</tt>.
92+ *
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&nbsp;?&nbsp;e==null&nbsp;:&nbsp;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
138+ * allocate a new array even if this set is backed by an array).
139+ * The caller is thus free to modify the returned array.
140+ *
141+ * <p>This method acts as bridge between array-based and collection-based
142+ * APIs.
143+ *
144+ * @return an array containing all the elements in this set
145+ */
146+ Object[] toArray();
147+
148+ /**
149+ * Returns an array containing all of the elements in this set; the
150+ * runtime type of the returned array is that of the specified array.
151+ * If the set fits in the specified array, it is returned therein.
152+ * Otherwise, a new array is allocated with the runtime type of the
153+ * specified array and the size of this set.
154+ *
155+ * <p>If this set fits in the specified array with room to spare
156+ * (i.e., the array has more elements than this set), the element in
157+ * the array immediately following the end of the set is set to
158+ * <tt>null</tt>. (This is useful in determining the length of this
159+ * set <i>only</i> if the caller knows that this set does not contain
160+ * any null elements.)
161+ *
162+ * <p>If this set makes any guarantees as to what order its elements
163+ * are returned by its iterator, this method must return the elements
164+ * in the same order.
165+ *
166+ * <p>Like the {@link #toArray()} method, this method acts as bridge between
167+ * array-based and collection-based APIs. Further, this method allows
168+ * precise control over the runtime type of the output array, and may,
169+ * under certain circumstances, be used to save allocation costs.
170+ *
171+ * <p>Suppose <tt>x</tt> is a set known to contain only strings.
172+ * The following code can be used to dump the set into a newly allocated
173+ * array of <tt>String</tt>:
174+ *
175+ * <pre>
176+ * String[] y = x.toArray(new String[0]);</pre>
177+ *
178+ * Note that <tt>toArray(new Object[0])</tt> is identical in function to
179+ * <tt>toArray()</tt>.
180+ *
181+ * @param a the array into which the elements of this set are to be
182+ * stored, if it is big enough; otherwise, a new array of the same
183+ * runtime type is allocated for this purpose.
184+ * @return an array containing all the elements in this set
185+ * @throws ArrayStoreException if the runtime type of the specified array
186+ * is not a supertype of the runtime type of every element in this
187+ * set
188+ * @throws NullPointerException if the specified array is null
189+ */
190+ <T> T[] toArray(T[] a);
191+
192+
193+ // Modification Operations
194+
195+ /**
196+ * Adds the specified element to this set if it is not already present
197+ * (optional operation). More formally, adds the specified element
198+ * <tt>e</tt> to this set if the set contains no element <tt>e2</tt>
199+ * such that
200+ * <tt>(e==null&nbsp;?&nbsp;e2==null&nbsp;:&nbsp;e.equals(e2))</tt>.
201+ * If this set already contains the element, the call leaves the set
202+ * unchanged and returns <tt>false</tt>. In combination with the
203+ * restriction on constructors, this ensures that sets never contain
204+ * duplicate elements.
205+ *
206+ * <p>The stipulation above does not imply that sets must accept all
207+ * elements; sets may refuse to add any particular element, including
208+ * <tt>null</tt>, and throw an exception, as described in the
209+ * specification for {@link Collection#add Collection.add}.
210+ * Individual set implementations should clearly document any
211+ * restrictions on the elements that they may contain.
212+ *
213+ * @param e element to be added to this set
214+ * @return <tt>true</tt> if this set did not already contain the specified
215+ * element
216+ * @throws UnsupportedOperationException if the <tt>add</tt> operation
217+ * is not supported by this set
218+ * @throws ClassCastException if the class of the specified element
219+ * prevents it from being added to this set
220+ * @throws NullPointerException if the specified element is null and this
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&nbsp;?&nbsp;e==null&nbsp;:&nbsp;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
291+ * or more null elements and this set does not permit null
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
359+ * <tt>true</tt> if the specified object is also a set, the two sets
360+ * have the same size, and every member of the specified set is
361+ * contained in this set (or equivalently, every member of this set is
362+ * contained in the specified set). This definition ensures that the
363+ * equals method works properly across different implementations of the
364+ * set interface.
365+ *
366+ * @param o object to be compared for equality with this set
367+ * @return <tt>true</tt> if the specified object is equal to this set
368+ */
369+ boolean equals(Object o);
370+
371+ /**
372+ * Returns the hash code value for this set. The hash code of a set is
373+ * defined to be the sum of the hash codes of the elements in the set,
374+ * where the hash code of a <tt>null</tt> element is defined to be zero.
375+ * This ensures that <tt>s1.equals(s2)</tt> implies that
376+ * <tt>s1.hashCode()==s2.hashCode()</tt> for any two sets <tt>s1</tt>
377+ * and <tt>s2</tt>, as required by the general contract of
378+ * {@link Object#hashCode}.
379+ *
380+ * @return the hash code value for this set
381+ * @see Object#equals(Object)
382+ * @see Set#equals(Object)
383+ */
384+ int hashCode();
385+}