/*
* 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;
}
}