/* * Distributed as part of debuggen v.0.1.0 * * Copyright (C) 2005 Machinery For Change, Inc. * * Author: Steve Waldman <swaldman@mchange.com> * * This library is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License version 2.1, as  * published by the Free Software Foundation. * * This software 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 software; see the file LICENSE.  If not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. */package com.mchange.v1.util;import java.util.Iterator;import java.util.Set;import java.util.AbstractSet;import java.util.HashSet;public final class SetUtils{    public static Set oneElementUnmodifiableSet(final Object elem)    {	return new AbstractSet()	    {		public Iterator iterator()		{ return IteratorUtils.oneElementUnmodifiableIterator( elem ); }		public int size() { return 1; }		public boolean isEmpty()		{ return false; }		public boolean contains(Object o) 		{ return o == elem; }	    };    }    public static Set setFromArray(Object[] array)    {	HashSet out = new HashSet();	for (int i = 0, len = array.length; i < len; ++i)	    out.add( array[i] );	return out;    }    public static boolean equivalentDisregardingSort(Set a, Set b)    {	return 	    a.containsAll( b ) &&	    b.containsAll( a );    }    /**     * finds a hash value which takes into account     * the value of all elements, such that two sets     * for which equivalentDisregardingSort(a, b) returns     * true will hashContentsDisregardingSort() to the same value     */    public static int hashContentsDisregardingSort(Set s)    {	int out = 0;	for (Iterator ii = s.iterator(); ii.hasNext(); )	    {		Object o = ii.next();		if (o != null) out ^= o.hashCode();	    }	return out;    }}