/* * Copyright (c) 2005, John Mettraux, OpenWFE.org * All rights reserved. *  * Redistribution and use in source and binary forms, with or without  * modification, are permitted provided that the following conditions are met: *  * . Redistributions of source code must retain the above copyright notice, this *   list of conditions and the following disclaimer.   *  * . 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. *  * . Neither the name of the "OpenWFE" nor the names of its contributors may be *   used to endorse or promote products derived from this software without *   specific prior written permission. *  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"  * AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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. * * $Id: SetUtils.java,v 1.3 2005/05/17 16:40:59 jmettraux Exp $ *///// SetUtils.java//// john.mettraux@openwfe.org//// generated with // jtmpl 1.1.01 2004/05/19 (john.mettraux@openwfe.org)//package openwfe.org.query.sets;/** * Methods about sets [of results]. * * <p><font size=2>CVS Info : * <br>$Author: jmettraux $ * <br>$Id: SetUtils.java,v 1.3 2005/05/17 16:40:59 jmettraux Exp $ </font> * * @author john.mettraux@openwfe.org */public abstract class SetUtils{    private final static org.apache.log4j.Logger log = org.apache.log4j.Logger        .getLogger(SetUtils.class.getName());    //    // STATIC METHODS    /**     * Inverts a set.     */    public static Set doNot (final Set s)    {        final Set result = (Set)s.clone();        result.invert();        return result;    }    /**     * Returns a set that is the union of two sets, ie whose elements     * belong to either s1 or s2.     */    public static Set doUnion (Set s1, Set s2)    {        if (s1.isNegative() && s2.isNegative())            return doNot(doIntersection(doNot(s1), doNot(s2)));        if (s1.isPositive() && s2.isPositive())        {            final Set result = (Set)s1.clone();            final java.util.Iterator it = s2.iterator();            while (it.hasNext())                result.add(it.next());            return result;        }        if (s1.isNegative())        {            final Set tmp = s1;            s1 = s2;            s2 = tmp;        }        final Set result = (Set)s1.clone();        final java.util.Iterator it = s2.iterator();        while (it.hasNext())            result.remove(it.next());        return result;    }    /**     * Returns a set whose elements belong to both s1 and s2.     */    public static Set doIntersection (Set s1, Set s2)    {        if (s1.isEmpty() || s2.isEmpty()) return s1.newInstance();            // shortcut        if (s1.isNegative() && s2.isNegative())            return doNot(doUnion(doNot(s1), doNot(s2)));        if (s1.isPositive() && s2.isPositive())        {            final Set result = s1.newInstance();            final java.util.Iterator it = s1.iterator();            while (it.hasNext())            {                final Object o = it.next();                if (s2.contains(o))                    result.add(o);            }            return result;        }        if (s1.isNegative())        {            final Set tmp = s1;            s1 = (Set)s2.clone();            s2 = tmp;        }        final java.util.Iterator it = s2.iterator();        while (it.hasNext())        {            final Object o = it.next();            if (s1.contains(o))                s1.remove(o);        }        return s1;    }}