ingo@1115: /*
ingo@1115:  * Copyright (c) 2010 by Intevation GmbH
ingo@1115:  *
ingo@1115:  * This program is free software under the LGPL (>=v2.1)
ingo@1115:  * Read the file LGPL.txt coming with the software for details
ingo@1115:  * or visit http://www.gnu.org/licenses/ if it does not exist.
ingo@1115:  */
ingo@1115: 
sascha@431: package de.intevation.gnv.math;
sascha@431: 
sascha@431: import java.io.Serializable;
sascha@431: 
sascha@431: /**
sascha@798:  * Tuple (i, j) to model a pair of integers. Useful to store index pairs
sascha@798:  * in maps.
sascha@780:  * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
sascha@431:  */
sascha@431: public class IJKey
sascha@431: implements   Serializable
sascha@431: {
sascha@798:     /**
sascha@798:      * i component of the tuple.
sascha@798:      */
sascha@431:     public int i;
sascha@798:     /**
sascha@798:      * j component of the tuple.
sascha@798:      */
sascha@431:     public int j;
sascha@431: 
sascha@798:     /**
sascha@798:      * Default constructor.
sascha@798:      */
sascha@431:     public IJKey() {
sascha@431:     }
sascha@431: 
sascha@798:     /**
sascha@798:      * Constructor to set i and j.
sascha@798:      * @param i The i component.
sascha@798:      * @param j The j component.
sascha@798:      */
sascha@431:     public IJKey(int i, int j) {
sascha@431:         this.i = i;
sascha@431:         this.j = j;
sascha@431:     }
sascha@431: 
sascha@798:     /**
sascha@798:      * Orders i and j by their values.
sascha@798:      */
sascha@437:     public void sort() {
sascha@437:         if (i > j) {
sascha@437:             int t = i;
sascha@437:             i = j;
sascha@437:             j = t;
sascha@437:         }
sascha@437:     }
sascha@437: 
sascha@798:     /**
sascha@798:      * Hashes i and j into a common value.
sascha@801:      * @return the hash code.
sascha@798:      */
sascha@798:     @Override
sascha@431:     public int hashCode() {
sascha@431:         return (i << 16) | j;
sascha@431:     }
sascha@431: 
sascha@798:     /**
sascha@798:      * IJKeys are considered equal if the i and j components
sascha@798:      * are equal.
sascha@798:      * @param obj The other IJKey
sascha@798:      * @return true if the IJKeys are equal else false.
sascha@798:      */
sascha@798:     @Override
sascha@431:     public boolean equals(Object obj) {
sascha@798:         if (!(obj instanceof IJKey)) {
sascha@798:             return false;
sascha@798:         }
sascha@431:         IJKey other = (IJKey)obj;
sascha@431:         return i == other.i && j == other.j;
sascha@431:     }
sascha@431: }
sascha@798: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :