AtomContainerComparatorBy2DCenter.java

/*  
*  Copyright (C) 2009  Mark Rijnbeek <markrynbeek@gmail.com>
*
*  Contact: cdk-devel@list.sourceforge.net
*
*  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 2.1
*  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 St, Fifth Floor, Boston, MA 02110-1301 USA.
*/

package org.openscience.cdk.tools.manipulator;

import java.util.Comparator;

import javax.vecmath.Point2d;

import org.openscience.cdk.geometry.GeometryTools;
import org.openscience.cdk.interfaces.IAtomContainer;

/**
 * Compares two IAtomContainers based on their 2D position.
 * <p>
 * Implemented specifically to be used in JChemPaint.
 *
 * @author Mark Rijnbeek
 * @cdk.created  2009-10-14
 * @cdk.module   standard
 */

public class AtomContainerComparatorBy2DCenter implements Comparator<IAtomContainer> {


    /** 
     * Compare two AtomContainers based on their 2D position.
     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
     */
    public int compare(IAtomContainer atCont1, IAtomContainer atCont2) {
        if(atCont1!=null && atCont2!=null) {
            Point2d p1= GeometryTools.get2DCenter(atCont1);
            Point2d p2= GeometryTools.get2DCenter(atCont2);
            if (p1!=null && p2!=null) {
                if (p1.x!=p2.x) {
                    return new Double(p1.x).compareTo(new Double(p2.x));
                }
                else {
                    return new Double(p1.y).compareTo(new Double(p2.y));
                }
            }
        }
        return 0;
    }
}