--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/util/Set.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,413 @@
+/*
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util;
+
+/**
+ * A collection that contains no duplicate elements. More formally, sets
+ * contain no pair of elements <code>e1</code> and <code>e2</code> such that
+ * <code>e1.equals(e2)</code>, and at most one null element. As implied by
+ * its name, this interface models the mathematical <i>set</i> abstraction.
+ *
+ * <p>The <tt>Set</tt> interface places additional stipulations, beyond those
+ * inherited from the <tt>Collection</tt> interface, on the contracts of all
+ * constructors and on the contracts of the <tt>add</tt>, <tt>equals</tt> and
+ * <tt>hashCode</tt> methods. Declarations for other inherited methods are
+ * also included here for convenience. (The specifications accompanying these
+ * declarations have been tailored to the <tt>Set</tt> interface, but they do
+ * not contain any additional stipulations.)
+ *
+ * <p>The additional stipulation on constructors is, not surprisingly,
+ * that all constructors must create a set that contains no duplicate elements
+ * (as defined above).
+ *
+ * <p>Note: Great care must be exercised if mutable objects are used as set
+ * elements. The behavior of a set is not specified if the value of an object
+ * is changed in a manner that affects <tt>equals</tt> comparisons while the
+ * object is an element in the set. A special case of this prohibition is
+ * that it is not permissible for a set to contain itself as an element.
+ *
+ * <p>Some set implementations have restrictions on the elements that
+ * they may contain. For example, some implementations prohibit null elements,
+ * and some have restrictions on the types of their elements. Attempting to
+ * add an ineligible element throws an unchecked exception, typically
+ * <tt>NullPointerException</tt> or <tt>ClassCastException</tt>. Attempting
+ * to query the presence of an ineligible element may throw an exception,
+ * or it may simply return false; some implementations will exhibit the former
+ * behavior and some will exhibit the latter. More generally, attempting an
+ * operation on an ineligible element whose completion would not result in
+ * the insertion of an ineligible element into the set may throw an
+ * exception or it may succeed, at the option of the implementation.
+ * Such exceptions are marked as "optional" in the specification for this
+ * interface.
+ *
+ * <p>This interface is a member of the
+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @param <E> the type of elements maintained by this set
+ *
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @see Collection
+ * @see List
+ * @see SortedSet
+ * @see HashSet
+ * @see TreeSet
+ * @see AbstractSet
+ * @see Collections#singleton(java.lang.Object)
+ * @see Collections#EMPTY_SET
+ * @since 1.2
+ */
+
+public interface Set<E> extends Collection<E> {
+ // Query Operations
+
+ /**
+ * Returns the number of elements in this set (its cardinality). If this
+ * set contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
+ * <tt>Integer.MAX_VALUE</tt>.
+ *
+ * @return the number of elements in this set (its cardinality)
+ */
+ int size();
+
+ /**
+ * Returns <tt>true</tt> if this set contains no elements.
+ *
+ * @return <tt>true</tt> if this set contains no elements
+ */
+ boolean isEmpty();
+
+ /**
+ * Returns <tt>true</tt> if this set contains the specified element.
+ * More formally, returns <tt>true</tt> if and only if this set
+ * contains an element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>.
+ *
+ * @param o element whose presence in this set is to be tested
+ * @return <tt>true</tt> if this set contains the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this set
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws NullPointerException if the specified element is null and this
+ * set does not permit null elements
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ */
+ boolean contains(Object o);
+
+ /**
+ * Returns an iterator over the elements in this set. The elements are
+ * returned in no particular order (unless this set is an instance of some
+ * class that provides a guarantee).
+ *
+ * @return an iterator over the elements in this set
+ */
+ Iterator<E> iterator();
+
+ /**
+ * Returns an array containing all of the elements in this set.
+ * If this set makes any guarantees as to what order its elements
+ * are returned by its iterator, this method must return the
+ * elements in the same order.
+ *
+ * <p>The returned array will be "safe" in that no references to it
+ * are maintained by this set. (In other words, this method must
+ * allocate a new array even if this set is backed by an array).
+ * The caller is thus free to modify the returned array.
+ *
+ * <p>This method acts as bridge between array-based and collection-based
+ * APIs.
+ *
+ * @return an array containing all the elements in this set
+ */
+ Object[] toArray();
+
+ /**
+ * Returns an array containing all of the elements in this set; the
+ * runtime type of the returned array is that of the specified array.
+ * If the set fits in the specified array, it is returned therein.
+ * Otherwise, a new array is allocated with the runtime type of the
+ * specified array and the size of this set.
+ *
+ * <p>If this set fits in the specified array with room to spare
+ * (i.e., the array has more elements than this set), the element in
+ * the array immediately following the end of the set is set to
+ * <tt>null</tt>. (This is useful in determining the length of this
+ * set <i>only</i> if the caller knows that this set does not contain
+ * any null elements.)
+ *
+ * <p>If this set makes any guarantees as to what order its elements
+ * are returned by its iterator, this method must return the elements
+ * in the same order.
+ *
+ * <p>Like the {@link #toArray()} method, this method acts as bridge between
+ * array-based and collection-based APIs. Further, this method allows
+ * precise control over the runtime type of the output array, and may,
+ * under certain circumstances, be used to save allocation costs.
+ *
+ * <p>Suppose <tt>x</tt> is a set known to contain only strings.
+ * The following code can be used to dump the set into a newly allocated
+ * array of <tt>String</tt>:
+ *
+ * <pre>
+ * String[] y = x.toArray(new String[0]);</pre>
+ *
+ * Note that <tt>toArray(new Object[0])</tt> is identical in function to
+ * <tt>toArray()</tt>.
+ *
+ * @param a the array into which the elements of this set are to be
+ * stored, if it is big enough; otherwise, a new array of the same
+ * runtime type is allocated for this purpose.
+ * @return an array containing all the elements in this set
+ * @throws ArrayStoreException if the runtime type of the specified array
+ * is not a supertype of the runtime type of every element in this
+ * set
+ * @throws NullPointerException if the specified array is null
+ */
+ <T> T[] toArray(T[] a);
+
+
+ // Modification Operations
+
+ /**
+ * Adds the specified element to this set if it is not already present
+ * (optional operation). More formally, adds the specified element
+ * <tt>e</tt> to this set if the set contains no element <tt>e2</tt>
+ * such that
+ * <tt>(e==null ? e2==null : e.equals(e2))</tt>.
+ * If this set already contains the element, the call leaves the set
+ * unchanged and returns <tt>false</tt>. In combination with the
+ * restriction on constructors, this ensures that sets never contain
+ * duplicate elements.
+ *
+ * <p>The stipulation above does not imply that sets must accept all
+ * elements; sets may refuse to add any particular element, including
+ * <tt>null</tt>, and throw an exception, as described in the
+ * specification for {@link Collection#add Collection.add}.
+ * Individual set implementations should clearly document any
+ * restrictions on the elements that they may contain.
+ *
+ * @param e element to be added to this set
+ * @return <tt>true</tt> if this set did not already contain the specified
+ * element
+ * @throws UnsupportedOperationException if the <tt>add</tt> operation
+ * is not supported by this set
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this set
+ * @throws NullPointerException if the specified element is null and this
+ * set does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified element
+ * prevents it from being added to this set
+ */
+ boolean add(E e);
+
+
+ /**
+ * Removes the specified element from this set if it is present
+ * (optional operation). More formally, removes an element <tt>e</tt>
+ * such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>, if
+ * this set contains such an element. Returns <tt>true</tt> if this set
+ * contained the element (or equivalently, if this set changed as a
+ * result of the call). (This set will not contain the element once the
+ * call returns.)
+ *
+ * @param o object to be removed from this set, if present
+ * @return <tt>true</tt> if this set contained the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this set
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws NullPointerException if the specified element is null and this
+ * set does not permit null elements
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws UnsupportedOperationException if the <tt>remove</tt> operation
+ * is not supported by this set
+ */
+ boolean remove(Object o);
+
+
+ // Bulk Operations
+
+ /**
+ * Returns <tt>true</tt> if this set contains all of the elements of the
+ * specified collection. If the specified collection is also a set, this
+ * method returns <tt>true</tt> if it is a <i>subset</i> of this set.
+ *
+ * @param c collection to be checked for containment in this set
+ * @return <tt>true</tt> if this set contains all of the elements of the
+ * specified collection
+ * @throws ClassCastException if the types of one or more elements
+ * in the specified collection are incompatible with this
+ * set
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this set does not permit null
+ * elements
+ * (<a href="Collection.html#optional-restrictions">optional</a>),
+ * or if the specified collection is null
+ * @see #contains(Object)
+ */
+ boolean containsAll(Collection<?> c);
+
+ /**
+ * Adds all of the elements in the specified collection to this set if
+ * they're not already present (optional operation). If the specified
+ * collection is also a set, the <tt>addAll</tt> operation effectively
+ * modifies this set so that its value is the <i>union</i> of the two
+ * sets. The behavior of this operation is undefined if the specified
+ * collection is modified while the operation is in progress.
+ *
+ * @param c collection containing elements to be added to this set
+ * @return <tt>true</tt> if this set changed as a result of the call
+ *
+ * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
+ * is not supported by this set
+ * @throws ClassCastException if the class of an element of the
+ * specified collection prevents it from being added to this set
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this set does not permit null
+ * elements, or if the specified collection is null
+ * @throws IllegalArgumentException if some property of an element of the
+ * specified collection prevents it from being added to this set
+ * @see #add(Object)
+ */
+ boolean addAll(Collection<? extends E> c);
+
+ /**
+ * Retains only the elements in this set that are contained in the
+ * specified collection (optional operation). In other words, removes
+ * from this set all of its elements that are not contained in the
+ * specified collection. If the specified collection is also a set, this
+ * operation effectively modifies this set so that its value is the
+ * <i>intersection</i> of the two sets.
+ *
+ * @param c collection containing elements to be retained in this set
+ * @return <tt>true</tt> if this set changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
+ * is not supported by this set
+ * @throws ClassCastException if the class of an element of this set
+ * is incompatible with the specified collection
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws NullPointerException if this set contains a null element and the
+ * specified collection does not permit null elements
+ * (<a href="Collection.html#optional-restrictions">optional</a>),
+ * or if the specified collection is null
+ * @see #remove(Object)
+ */
+ boolean retainAll(Collection<?> c);
+
+ /**
+ * Removes from this set all of its elements that are contained in the
+ * specified collection (optional operation). If the specified
+ * collection is also a set, this operation effectively modifies this
+ * set so that its value is the <i>asymmetric set difference</i> of
+ * the two sets.
+ *
+ * @param c collection containing elements to be removed from this set
+ * @return <tt>true</tt> if this set changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
+ * is not supported by this set
+ * @throws ClassCastException if the class of an element of this set
+ * is incompatible with the specified collection
+ * (<a href="Collection.html#optional-restrictions">optional</a>)
+ * @throws NullPointerException if this set contains a null element and the
+ * specified collection does not permit null elements
+ * (<a href="Collection.html#optional-restrictions">optional</a>),
+ * or if the specified collection is null
+ * @see #remove(Object)
+ * @see #contains(Object)
+ */
+ boolean removeAll(Collection<?> c);
+
+ /**
+ * Removes all of the elements from this set (optional operation).
+ * The set will be empty after this call returns.
+ *
+ * @throws UnsupportedOperationException if the <tt>clear</tt> method
+ * is not supported by this set
+ */
+ void clear();
+
+
+ // Comparison and hashing
+
+ /**
+ * Compares the specified object with this set for equality. Returns
+ * <tt>true</tt> if the specified object is also a set, the two sets
+ * have the same size, and every member of the specified set is
+ * contained in this set (or equivalently, every member of this set is
+ * contained in the specified set). This definition ensures that the
+ * equals method works properly across different implementations of the
+ * set interface.
+ *
+ * @param o object to be compared for equality with this set
+ * @return <tt>true</tt> if the specified object is equal to this set
+ */
+ boolean equals(Object o);
+
+ /**
+ * Returns the hash code value for this set. The hash code of a set is
+ * defined to be the sum of the hash codes of the elements in the set,
+ * where the hash code of a <tt>null</tt> element is defined to be zero.
+ * This ensures that <tt>s1.equals(s2)</tt> implies that
+ * <tt>s1.hashCode()==s2.hashCode()</tt> for any two sets <tt>s1</tt>
+ * and <tt>s2</tt>, as required by the general contract of
+ * {@link Object#hashCode}.
+ *
+ * @return the hash code value for this set
+ * @see Object#equals(Object)
+ * @see Set#equals(Object)
+ */
+ int hashCode();
+
+ /**
+ * Creates a {@code Spliterator} over the elements in this set.
+ *
+ * <p>The {@code Spliterator} reports {@link Spliterator#DISTINCT}.
+ * Implementations should document the reporting of additional
+ * characteristic values.
+ *
+ * @implSpec
+ * The default implementation creates a
+ * <em><a href="Spliterator.html#binding">late-binding</a></em> spliterator
+ * from the set's {@code Iterator}. The spliterator inherits the
+ * <em>fail-fast</em> properties of the set's iterator.
+ * <p>
+ * The created {@code Spliterator} additionally reports
+ * {@link Spliterator#SIZED}.
+ *
+ * @implNote
+ * The created {@code Spliterator} additionally reports
+ * {@link Spliterator#SUBSIZED}.
+ *
+ * @return a {@code Spliterator} over the elements in this set
+ * @since 1.8
+ */
+ @Override
+ default Spliterator<E> spliterator() {
+ return Spliterators.spliterator(this, Spliterator.DISTINCT);
+ }
+}