1 /*
2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. 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
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7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle 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.
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24  */
25 
26 package com.sun.tools.javac.util;
27 
28 import java.util.Objects;
29 
30 /** A generic class for pairs.
31  *
32  *  <p><b>This is NOT part of any supported API.
33  *  If you write code that depends on this, you do so at your own risk.
34  *  This code and its internal interfaces are subject to change or
35  *  deletion without notice.</b>
36  */
37 public class Pair<A, B> {
38 
39     public final A fst;
40     public final B snd;
41 
Pair(A fst, B snd)42     public Pair(A fst, B snd) {
43         this.fst = fst;
44         this.snd = snd;
45     }
46 
toString()47     public String toString() {
48         return "Pair[" + fst + "," + snd + "]";
49     }
50 
equals(Object other)51     public boolean equals(Object other) {
52         return
53             other instanceof Pair<?,?> &&
54             Objects.equals(fst, ((Pair<?,?>)other).fst) &&
55             Objects.equals(snd, ((Pair<?,?>)other).snd);
56     }
57 
hashCode()58     public int hashCode() {
59         if (fst == null) return (snd == null) ? 0 : snd.hashCode() + 1;
60         else if (snd == null) return fst.hashCode() + 2;
61         else return fst.hashCode() * 17 + snd.hashCode();
62     }
63 
of(A a, B b)64     public static <A,B> Pair<A,B> of(A a, B b) {
65         return new Pair<>(a,b);
66     }
67 }
68