Mercurial > hg > blitz_condensed
diff src/com/go/trove/util/MapBackedSet.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/com/go/trove/util/MapBackedSet.java Sat Mar 21 11:00:06 2009 +0000 @@ -0,0 +1,142 @@ +/* ==================================================================== + * Trove - Copyright (c) 1997-2000 Walt Disney Internet Group + * ==================================================================== + * The Tea Software License, Version 1.1 + * + * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. The end-user documentation included with the redistribution, + * if any, must include the following acknowledgment: + * "This product includes software developed by the + * Walt Disney Internet Group (http://opensource.go.com/)." + * Alternately, this acknowledgment may appear in the software itself, + * if and wherever such third-party acknowledgments normally appear. + * + * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must + * not be used to endorse or promote products derived from this + * software without prior written permission. For written + * permission, please contact opensource@dig.com. + * + * 5. Products derived from this software may not be called "Tea", + * "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet", + * "Kettle", "Trove" or "BeanDoc" appear in their name, without prior + * written permission of the Walt Disney Internet Group. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * ==================================================================== + * + * For more information about Tea, please see http://opensource.go.com/. + */ + +package com.go.trove.util; + +import java.util.*; + +/****************************************************************************** + * A set implementation that is backed by any map. + * + * @author Brian S O'Neill + * @version + * <!--$$Revision: 1.1 $-->, <!--$$JustDate:--> 9/07/00 <!-- $--> + */ +public class MapBackedSet extends AbstractSet implements java.io.Serializable { + // Dummy value to associate with an Object in the backing Map + private static final Object PRESENT = new Object(); + + protected final Map mMap; + + /** + * @param map The map to back this set. + */ + public MapBackedSet(Map map) { + mMap = map; + } + + /** + * Returns an iterator over the elements in this set. The elements + * are returned in the order determined by the backing map. + * + * @return an Iterator over the elements in this set. + * @see ConcurrentModificationException + */ + public Iterator iterator() { + return mMap.keySet().iterator(); + } + + /** + * Returns the number of elements in this set (its cardinality). + * + * @return the number of elements in this set (its cardinality). + */ + public int size() { + return mMap.size(); + } + + /** + * Returns true if this set contains no elements. + * + * @return true if this set contains no elements. + */ + public boolean isEmpty() { + return mMap.isEmpty(); + } + + /** + * Returns true if this set contains the specified element. + * + * @return true if this set contains the specified element. + */ + public boolean contains(Object obj) { + return mMap.containsKey(obj); + } + + /** + * Adds the specified element to this set if it is not already + * present. + * + * @param obj element to be added to this set. + * @return true if the set did not already contain the specified element. + */ + public boolean add(Object obj) { + return mMap.put(obj, PRESENT) == null; + } + + /** + * Removes the given element from this set if it is present. + * + * @param obj object to be removed from this set, if present. + * @return true if the set contained the specified element. + */ + public boolean remove(Object obj) { + return mMap.remove(obj) == PRESENT; + } + + /** + * Removes all of the elements from this set. + */ + public void clear() { + mMap.clear(); + } +}