/*
* dk.brics.automaton
*
* Copyright (c) 2001-2009 Anders Moeller
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
package org.apache.lucene.util.automaton;
/**
* Pair of states.
*
* @lucene.experimental
*/
public class StatePair {
int s;
int s1;
int s2;
StatePair(int s, int s1, int s2) {
this.s = s;
this.s1 = s1;
this.s2 = s2;
}
/**
* Constructs a new state pair.
*
* @param s1 first state
* @param s2 second state
*/
public StatePair(int s1, int s2) {
this.s1 = s1;
this.s2 = s2;
this.s = -1;
}
/**
* Checks for equality.
*
* @param obj object to compare with
* @return true if <tt>obj</tt> represents the same pair of states as this
* pair
*/
@Override
public boolean equals(Object obj) {
if (obj instanceof StatePair) {
StatePair p = (StatePair) obj;
return p.s1 == s1 && p.s2 == s2;
} else return false;
}
/**
* Returns hash code.
*
* @return hash code
*/
@Override
public int hashCode() {
// Don't use s1 ^ s2 since it's vulnerable to the case where s1 == s2 always --> hashCode = 0, e.g. if you call Operations.sameLanguage,
// passing the same automaton against itself:
return s1 * 31 + s2;
}
@Override
public String toString() {
return "StatePair(s1=" + s1 + " s2=" + s2 + ")";
}
}