duke@1: /*
ohair@554:  * Copyright (c) 1999, 2005, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
ohair@554:  * published by the Free Software Foundation.  Oracle designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
ohair@554:  * by Oracle in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.tools.javac.util;
duke@1: 
duke@1: /** A generic class for pairs.
duke@1:  *
jjg@581:  *  <p><b>This is NOT part of any supported API.
jjg@581:  *  If you write code that depends on this, you do so at your own risk.
duke@1:  *  This code and its internal interfaces are subject to change or
duke@1:  *  deletion without notice.</b>
duke@1:  */
duke@1: public class Pair<A, B> {
duke@1: 
duke@1:     public final A fst;
duke@1:     public final B snd;
duke@1: 
duke@1:     public Pair(A fst, B snd) {
duke@1:         this.fst = fst;
duke@1:         this.snd = snd;
duke@1:     }
duke@1: 
duke@1:     public String toString() {
duke@1:         return "Pair[" + fst + "," + snd + "]";
duke@1:     }
duke@1: 
duke@1:     private static boolean equals(Object x, Object y) {
duke@1:         return (x == null && y == null) || (x != null && x.equals(y));
duke@1:     }
duke@1: 
duke@1:     public boolean equals(Object other) {
duke@1:         return
mcimadamore@184:             other instanceof Pair<?,?> &&
mcimadamore@184:             equals(fst, ((Pair<?,?>)other).fst) &&
mcimadamore@184:             equals(snd, ((Pair<?,?>)other).snd);
duke@1:     }
duke@1: 
duke@1:     public int hashCode() {
duke@1:         if (fst == null) return (snd == null) ? 0 : snd.hashCode() + 1;
duke@1:         else if (snd == null) return fst.hashCode() + 2;
duke@1:         else return fst.hashCode() * 17 + snd.hashCode();
duke@1:     }
duke@1: 
duke@1:     public static <A,B> Pair<A,B> of(A a, B b) {
duke@1:         return new Pair<A,B>(a,b);
duke@1:     }
duke@1: }