| 1 | /* |
| 2 | * Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.tools.javac.util; |
| 27 | |
| 28 | /** A generic class for pairs. |
| 29 | * |
| 30 | * <p><b>This is NOT part of any API supported by Sun Microsystems. If |
| 31 | * you write code that depends on this, you do so at your own risk. |
| 32 | * This code and its internal interfaces are subject to change or |
| 33 | * deletion without notice.</b> |
| 34 | */ |
| 35 | public class Pair<A, B> { |
| 36 | |
| 37 | public final A fst; |
| 38 | public final B snd; |
| 39 | |
| 40 | public Pair(A fst, B snd) { |
| 41 | this.fst = fst; |
| 42 | this.snd = snd; |
| 43 | } |
| 44 | |
| 45 | public String toString() { |
| 46 | return "Pair[" + fst + "," + snd + "]"; |
| 47 | } |
| 48 | |
| 49 | private static boolean equals(Object x, Object y) { |
| 50 | return (x == null && y == null) || (x != null && x.equals(y)); |
| 51 | } |
| 52 | |
| 53 | public boolean equals(Object other) { |
| 54 | return |
| 55 | other instanceof Pair && |
| 56 | equals(fst, ((Pair)other).fst) && |
| 57 | equals(snd, ((Pair)other).snd); |
| 58 | } |
| 59 | |
| 60 | public int hashCode() { |
| 61 | if (fst == null) return (snd == null) ? 0 : snd.hashCode() + 1; |
| 62 | else if (snd == null) return fst.hashCode() + 2; |
| 63 | else return fst.hashCode() * 17 + snd.hashCode(); |
| 64 | } |
| 65 | |
| 66 | public static <A,B> Pair<A,B> of(A a, B b) { |
| 67 | return new Pair<A,B>(a,b); |
| 68 | } |
| 69 | } |