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 | } |