| /* Set.java -- A collection that prohibits duplicates |
| Copyright (C) 1998, 2001, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
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| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.util; |
| |
| /** |
| * A collection that contains no duplicates. In other words, for two set |
| * elements e1 and e2, <code>e1.equals(e2)</code> returns false. There |
| * are additional stipulations on <code>add</code>, <code>equals</code> |
| * and <code>hashCode</code>, as well as the requirements that constructors |
| * do not permit duplicate elements. The Set interface is incompatible with |
| * List; you cannot implement both simultaneously. |
| * <p> |
| * |
| * Note: Be careful about using mutable objects in sets. In particular, |
| * if a mutable object changes to become equal to another set element, you |
| * have violated the contract. As a special case of this, a Set is not |
| * allowed to be an element of itself, without risking undefined behavior. |
| * |
| * @author Original author unknown |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * @see Collection |
| * @see List |
| * @see SortedSet |
| * @see HashSet |
| * @see TreeSet |
| * @see LinkedHashSet |
| * @see AbstractSet |
| * @see Collections#singleton(Object) |
| * @see Collections#EMPTY_SET |
| * @since 1.2 |
| * @status updated to 1.4 |
| */ |
| public interface Set extends Collection |
| { |
| /** |
| * Adds the specified element to the set if it is not already present |
| * (optional operation). In particular, the comparison algorithm is |
| * <code>o == null ? e == null : o.equals(e)</code>. Sets need not permit |
| * all values, and may document what exceptions will be thrown if |
| * a value is not permitted. |
| * |
| * @param o the object to add |
| * @return true if the object was not previously in the set |
| * @throws UnsupportedOperationException if this operation is not allowed |
| * @throws ClassCastException if the class of o prevents it from being added |
| * @throws IllegalArgumentException if some aspect of o prevents it from |
| * being added |
| * @throws NullPointerException if null is not permitted in this set |
| */ |
| boolean add(Object o); |
| |
| /** |
| * Adds all of the elements of the given collection to this set (optional |
| * operation). If the argument is also a Set, this returns the mathematical |
| * <i>union</i> of the two. The behavior is unspecified if the set is |
| * modified while this is taking place. |
| * |
| * @param c the collection to add |
| * @return true if the set changed as a result |
| * @throws UnsupportedOperationException if this operation is not allowed |
| * @throws ClassCastException if the class of an element prevents it from |
| * being added |
| * @throws IllegalArgumentException if something about an element prevents |
| * it from being added |
| * @throws NullPointerException if null is not permitted in this set, or |
| * if the argument c is null |
| * @see #add(Object) |
| */ |
| boolean addAll(Collection c); |
| |
| /** |
| * Removes all elements from this set (optional operation). This set will |
| * be empty afterwords, unless an exception occurs. |
| * |
| * @throws UnsupportedOperationException if this operation is not allowed |
| */ |
| void clear(); |
| |
| /** |
| * Returns true if the set contains the specified element. In other words, |
| * this looks for <code>o == null ? e == null : o.equals(e)</code>. |
| * |
| * @param o the object to look for |
| * @return true if it is found in the set |
| * @throws ClassCastException if the type of o is not a valid type |
| * for this set. |
| * @throws NullPointerException if o is null and this set doesn't |
| * support null values. |
| */ |
| boolean contains(Object o); |
| |
| /** |
| * Returns true if this set contains all elements in the specified |
| * collection. If the argument is also a set, this is the <i>subset</i> |
| * relationship. |
| * |
| * @param c the collection to check membership in |
| * @return true if all elements in this set are in c |
| * @throws NullPointerException if c is null |
| * @throws ClassCastException if the type of any element in c is not |
| * a valid type for this set. |
| * @throws NullPointerException if some element of c is null and this |
| * set doesn't support null values. |
| * @see #contains(Object) |
| */ |
| boolean containsAll(Collection c); |
| |
| /** |
| * Compares the specified object to this for equality. For sets, the object |
| * must be a set, the two must have the same size, and every element in |
| * one must be in the other. |
| * |
| * @param o the object to compare to |
| * @return true if it is an equal set |
| */ |
| boolean equals(Object o); |
| |
| /** |
| * Returns the hash code for this set. In order to satisfy the contract of |
| * equals, this is the sum of the hashcode of all elements in the set. |
| * |
| * @return the sum of the hashcodes of all set elements |
| * @see #equals(Object) |
| */ |
| int hashCode(); |
| |
| /** |
| * Returns true if the set contains no elements. |
| * |
| * @return true if the set is empty |
| */ |
| boolean isEmpty(); |
| |
| /** |
| * Returns an iterator over the set. The iterator has no specific order, |
| * unless further specified. |
| * |
| * @return a set iterator |
| */ |
| Iterator iterator(); |
| |
| /** |
| * Removes the specified element from this set (optional operation). If |
| * an element e exists, <code>o == null ? e == null : o.equals(e)</code>, |
| * it is removed from the set. |
| * |
| * @param o the object to remove |
| * @return true if the set changed (an object was removed) |
| * @throws UnsupportedOperationException if this operation is not allowed |
| * @throws ClassCastException if the type of o is not a valid type |
| * for this set. |
| * @throws NullPointerException if o is null and this set doesn't allow |
| * the removal of a null value. |
| */ |
| boolean remove(Object o); |
| |
| /** |
| * Removes from this set all elements contained in the specified collection |
| * (optional operation). If the argument is a set, this returns the |
| * <i>asymmetric set difference</i> of the two sets. |
| * |
| * @param c the collection to remove from this set |
| * @return true if this set changed as a result |
| * @throws UnsupportedOperationException if this operation is not allowed |
| * @throws NullPointerException if c is null |
| * @throws ClassCastException if the type of any element in c is not |
| * a valid type for this set. |
| * @throws NullPointerException if some element of c is null and this |
| * set doesn't support removing null values. |
| * @see #remove(Object) |
| */ |
| boolean removeAll(Collection c); |
| |
| /** |
| * Retains only the elements in this set that are also in the specified |
| * collection (optional operation). If the argument is also a set, this |
| * performs the <i>intersection</i> of the two sets. |
| * |
| * @param c the collection to keep |
| * @return true if this set was modified |
| * @throws UnsupportedOperationException if this operation is not allowed |
| * @throws NullPointerException if c is null |
| * @throws ClassCastException if the type of any element in c is not |
| * a valid type for this set. |
| * @throws NullPointerException if some element of c is null and this |
| * set doesn't support retaining null values. |
| * @see #remove(Object) |
| */ |
| boolean retainAll(Collection c); |
| |
| /** |
| * Returns the number of elements in the set. If there are more |
| * than Integer.MAX_VALUE mappings, return Integer.MAX_VALUE. This is |
| * the <i>cardinality</i> of the set. |
| * |
| * @return the number of elements |
| */ |
| int size(); |
| |
| /** |
| * Returns an array containing the elements of this set. If the set |
| * makes a guarantee about iteration order, the array has the same |
| * order. The array is distinct from the set; modifying one does not |
| * affect the other. |
| * |
| * @return an array of this set's elements |
| * @see #toArray(Object[]) |
| */ |
| Object[] toArray(); |
| |
| /** |
| * Returns an array containing the elements of this set, of the same runtime |
| * type of the argument. If the given set is large enough, it is reused, |
| * and null is inserted in the first unused slot. Otherwise, reflection |
| * is used to build a new array. If the set makes a guarantee about iteration |
| * order, the array has the same order. The array is distinct from the set; |
| * modifying one does not affect the other. |
| * |
| * @param a the array to determine the return type; if it is big enough |
| * it is used and returned |
| * @return an array holding the elements of the set |
| * @throws ArrayStoreException if the runtime type of a is not a supertype |
| * of all elements in the set |
| * @throws NullPointerException if a is null |
| * @see #toArray() |
| */ |
| Object[] toArray(Object[] a); |
| } |