/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-2014 The eXist Project
* http://exist-db.org
*
* This program 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
* of the License, or (at your option) any later version.
*
* This program 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 program; if not, write to the Free Software Foundation
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery.value;
import org.exist.xquery.Constants;
import java.util.Comparator;
/**
* Comparator for comparing instances of Item
* apart from the XQuery atomic types there are
* two Node types in eXist org.exist.dom.persistent.*
* and org.exist.dom.memtree.* this class is
* used so that both types can be compared to each other
* as Item even though they have quite different inheritance
* hierarchies.
*
* @author Adam Retter <adam.retter@googlemail.com>
*/
public class ItemComparator implements Comparator<Item> {
public final static ItemComparator INSTANCE = new ItemComparator();
private ItemComparator() {
}
@Override
public int compare(final Item n1, final Item n2) {
if (n1 instanceof org.exist.dom.memtree.NodeImpl && (!(n2 instanceof org.exist.dom.memtree.NodeImpl))) {
return Constants.INFERIOR;
} else if (n1 instanceof Comparable) {
return ((Comparable) n1).compareTo(n2);
} else {
return Constants.INFERIOR;
}
}
}