/*
 * Copyright (c) 2005, Stanford University. 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 Stanford University 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. 
 */

/*
 * Created on Jun 27, 2005
 *
 */
package org.simtk.molecularstructure.atom;

public class Bond {
    protected Atom atom1;
    protected Atom atom2;
    
    public Bond(Atom a1, Atom a2) {atom1 = a1; atom2 = a2;}

    public boolean equals(Object o) {
        if (! (o instanceof Bond)) return false;
        Bond bond2 = (Bond) o;
        if ( (atom1.equals(bond2.atom2)) &&
             (atom2.equals(bond2.atom2)) ) return true;
        // Swapping atom1 and atom2 is still the same bond
        if ( (atom2.equals(bond2.atom2)) &&
                (atom1.equals(bond2.atom2)) ) return true;
        return false;
    }
    public int hashCode() {
        // Must be symmetric with respect to atom1 vs. atom2
        return atom1.hashCode() + atom2.hashCode();
    }
}