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comparison src/clojure/lang/Util.java @ 10:ef7dbbd6452c

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added clojure source goodness
author Robert McIntyre <rlm@mit.edu>
date Sat, 21 Aug 2010 06:25:44 -0400
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9:35cf337adfcf 10:ef7dbbd6452c
1 /**
2 * Copyright (c) Rich Hickey. All rights reserved.
3 * The use and distribution terms for this software are covered by the
4 * Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
5 * which can be found in the file epl-v10.html at the root of this distribution.
6 * By using this software in any fashion, you are agreeing to be bound by
7 * the terms of this license.
8 * You must not remove this notice, or any other, from this software.
9 **/
10
11 /* rich Apr 19, 2008 */
12
13 package clojure.lang;
14
15 import java.math.BigInteger;
16 import java.util.Map;
17 import java.util.concurrent.ConcurrentHashMap;
18 import java.lang.ref.SoftReference;
19 import java.lang.ref.ReferenceQueue;
20 import java.lang.ref.Reference;
21
22 public class Util{
23 static public boolean equiv(Object k1, Object k2){
24 if(k1 == k2)
25 return true;
26 if(k1 != null)
27 {
28 if(k1 instanceof Number && k2 instanceof Number)
29 return Numbers.equiv(k1, k2);
30 else if(k1 instanceof IPersistentCollection || k2 instanceof IPersistentCollection)
31 return pcequiv(k1,k2);
32 return k1.equals(k2);
33 }
34 return false;
35 }
36
37 static public boolean pcequiv(Object k1, Object k2){
38 if(k1 instanceof IPersistentCollection)
39 return ((IPersistentCollection)k1).equiv(k2);
40 return ((IPersistentCollection)k2).equiv(k1);
41 }
42
43 static public boolean equals(Object k1, Object k2){
44 if(k1 == k2)
45 return true;
46 return k1 != null && k1.equals(k2);
47 }
48
49 static public boolean identical(Object k1, Object k2){
50 return k1 == k2;
51 }
52
53 static public Class classOf(Object x){
54 if(x != null)
55 return x.getClass();
56 return null;
57 }
58
59 static public int compare(Object k1, Object k2){
60 if(k1 == k2)
61 return 0;
62 if(k1 != null)
63 {
64 if(k2 == null)
65 return 1;
66 if(k1 instanceof Number)
67 return Numbers.compare((Number) k1, (Number) k2);
68 return ((Comparable) k1).compareTo(k2);
69 }
70 return -1;
71 }
72
73 static public int hash(Object o){
74 if(o == null)
75 return 0;
76 return o.hashCode();
77 }
78
79 static public int hashCombine(int seed, int hash){
80 //a la boost
81 seed ^= hash + 0x9e3779b9 + (seed << 6) + (seed >> 2);
82 return seed;
83 }
84
85 static public boolean isPrimitive(Class c){
86 return c != null && c.isPrimitive() && !(c == Void.TYPE);
87 }
88
89 static public boolean isInteger(Object x){
90 return x instanceof Integer
91 || x instanceof Long
92 || x instanceof BigInteger;
93 }
94
95 static public Object ret1(Object ret, Object nil){
96 return ret;
97 }
98
99 static public ISeq ret1(ISeq ret, Object nil){
100 return ret;
101 }
102
103 static public <K,V> void clearCache(ReferenceQueue rq, ConcurrentHashMap<K, SoftReference<V>> cache){
104 //cleanup any dead entries
105 if(rq.poll() != null)
106 {
107 while(rq.poll() != null)
108 ;
109 for(Map.Entry<K, SoftReference<V>> e : cache.entrySet())
110 {
111 if(e.getValue().get() == null)
112 cache.remove(e.getKey(), e.getValue());
113 }
114 }
115 }
116 }