01: /*
02: * Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved.
03: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04: *
05: * This code is free software; you can redistribute it and/or modify it
06: * under the terms of the GNU General Public License version 2 only, as
07: * published by the Free Software Foundation. Sun designates this
08: * particular file as subject to the "Classpath" exception as provided
09: * 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: @Version("@(#)Pair.java 1.25 07/05/05")
36: public class Pair<A, B> {
37:
38: public final A fst;
39: public final B snd;
40:
41: public Pair(A fst, B snd) {
42: this .fst = fst;
43: this .snd = snd;
44: }
45:
46: public String toString() {
47: return "Pair[" + fst + "," + snd + "]";
48: }
49:
50: private static boolean equals(Object x, Object y) {
51: return (x == null && y == null) || (x != null && x.equals(y));
52: }
53:
54: public boolean equals(Object other) {
55: return other instanceof Pair && equals(fst, ((Pair) other).fst)
56: && equals(snd, ((Pair) other).snd);
57: }
58:
59: public int hashCode() {
60: if (fst == null)
61: return (snd == null) ? 0 : snd.hashCode() + 1;
62: else if (snd == null)
63: return fst.hashCode() + 2;
64: else
65: return fst.hashCode() * 17 + snd.hashCode();
66: }
67:
68: public static <A, B> Pair<A, B> of(A a, B b) {
69: return new Pair<A, B>(a, b);
70: }
71: }
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