Small sets whose elements are known to be unique by construction

        
/* 
 * JGraphT : a free Java graph-theory library
 * 
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2007, by Barak Naveh and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* -----------------
 * ArrayUnenforcedSet.java
 * -----------------
 * (C) Copyright 2006-2007, by John V. Sichi and Contributors.
 *
 * Original Author:  John V. Sichi
 * Contributor(s):   -
 *
 * $Id: ArrayUnenforcedSet.java 568 2007-09-30 00:12:18Z perfecthash $
 *
 * Changes
 * -------
 * 07-May-2006 : Initial version (JVS);
 */

import java.util.*;


/**
 * Helper for efficiently representing small sets whose elements are known to be
 * unique by construction, implying we don't need to enforce the uniqueness
 * property in the data structure itself. Use with caution.
 *
 * <p>Note that for equals/hashCode, the class implements the Set behavior
 * (unordered), not the list behavior (ordered); the fact that it subclasses
 * ArrayList should be considered an implementation detail.
 *
 * @author John V. Sichi
 */
public class ArrayUnenforcedSet<E>
    extends ArrayList<E>
    implements Set<E>
{
    //~ Static fields/initializers ---------------------------------------------

    private static final long serialVersionUID = -7413250161201811238L;

    //~ Constructors -----------------------------------------------------------

    public ArrayUnenforcedSet()
    {
        super();
    }

    public ArrayUnenforcedSet(Collection<? extends E> c)
    {
        super(c);
    }

    public ArrayUnenforcedSet(int n)
    {
        super(n);
    }

    //~ Methods ----------------------------------------------------------------

    public boolean equals(Object o)
    {
        return new SetForEquality().equals(o);
    }

    public int hashCode()
    {
        return new SetForEquality().hashCode();
    }

    //~ Inner Classes ----------------------------------------------------------

    /**
     * Multiple inheritance helper.
     */
    private class SetForEquality
        extends AbstractSet<E>
    {
        public Iterator<E> iterator()
        {
            return ArrayUnenforcedSet.this.iterator();
        }

        public int size()
        {
            return ArrayUnenforcedSet.this.size();
        }
    }
}

// End ArrayUnenforcedSet.java

Related examples in the same category

1.	Set, HashSet and TreeSet
2.	Things you can do with Sets
3.	Set operations: union, intersection, difference, symmetric difference, is subset, is superset
4.	Set implementation that use == instead of equals()
5.	Set that compares object by identity rather than equality
6.	Set union and intersection
7.	Set with values iterated in insertion order.
8.	Putting your own type in a Set
9.	Use set
10.	Another Set demo
11.	Set subtraction
12.	Working with HashSet and TreeSet
13.	TreeSet Demo
14.	Show the union and intersection of two sets
15.	Demonstrate the Set interface
16.	Array Set extends AbstractSet
17.	Sync Test
18.	Set Copy
19.	Set and TreeSet
20.	Tail
21.	What you can do with a TreeSet
22.	Remove all elements from a set
23.	Copy all the elements from set2 to set1 (set1 += set2), set1 becomes the union of set1 and set2
24.	Remove all the elements in set1 from set2 (set1 -= set2), set1 becomes the asymmetric difference of set1 and set2
25.	Get the intersection of set1 and set2, set1 becomes the intersection of set1 and set2
26.	Extend AbstractSet to Create Simple Set
27.	Int Set
28.	One Item Set
29.	List Set implements Set
30.	Converts a char array to a Set
31.	Converts a string to a Set
32.	Implements the Set interface, backed by a ConcurrentHashMap instance
33.	An IdentitySet that uses reference-equality instead of object-equality
34.	An implementation of the java.util.Stack based on an ArrayList instead of a Vector, so it is not synchronized to protect against multi-threaded access.
35.	A thin wrapper around a List transforming it into a modifiable Set.
36.	A thread-safe Set that manages canonical objects
37.	This program uses a set to print all unique words in System.in
38.	Indexed Set
39.	An ObjectToSet provides a java.util.Map from arbitrary objects to objects of class java.util.Set.
40.	Sorted Multi Set
41.	Fixed Size Sorted Set
42.	Set operations
43.	A NumberedSet is a generic container of Objects where each element is identified by an integer id.
44.	Set which counts the number of times a values are added to it.
45.	Set which counts the number of times a values are added to it and assigns them a unique positive index.
46.	Indexed Set
47.	A set acts like array.
48.	Implements a Bloom filter. Which, as you may not know, is a space-efficient structure for storing a set.
49.	Implementation of disjoint-set data structure
50.	Call it an unordered list or a multiset, this collection is defined by oxymorons

Small sets whose elements are known to be unique by construction : Set « Collections Data Structure « Java

Related examples in the same category