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1
4 package com.tc.util;
5
6 import com.tc.logging.TCLogger;
7 import com.tc.logging.TCLogging;
8
9 import java.lang.reflect.Method  ;
10 import java.security.SecureRandom ;
11 import java.util.Random ;
12
13 public class UUID {
14
15 private static final TCLogger logger = TCLogging.getLogger(UUID.class);
16 private static final Method jdk15createMethod;
17
18 private final String uuid;
19
20 public static UUID getUUID() {
21 if (jdk15createMethod != null) { return new UUID(getJDK15()); }
22 return new UUID(getDefault());
23 }
24
25 private static String getDefault() {
26 Random r = new SecureRandom ();
27 long l1 = r.nextLong();
28 long l2 = r.nextLong();
29 return Long.toHexString(l1) + Long.toHexString(l2);
30 }
31
32 private static String getJDK15() {
33 try {
34 Object object = jdk15createMethod.invoke(null, new Object [] {});
35 String s = object.toString();
36 return s.replaceAll("[^A-Fa-f0-9]", "");
37 } catch (Exception e) {
38 throw new AssertionError (e);
39 }
40 }
41
42 public String toString() {
43 return uuid;
44 }
45
46 private UUID(String uuid) {
47 this.uuid = makeSize32(uuid);
48 if(32 != this.uuid.length()) {
49 throw new AssertionError ("UUID : length is not 32 but " + this.uuid.length() + " : UUID is : " + this.uuid);
50 }
51 }
52
53 private String makeSize32(String uuid2) {
55 int len = uuid2.length() ;
56 if(len < 32 ) {
57 StringBuffer sb = new StringBuffer (32);
58 while(len ++ < 32) {
59 sb.append('0');
60 }
61 sb.append(uuid2);
62 return sb.toString();
63 } else if ( len > 32) {
64 return uuid2.substring(0, 32);
65 } else {
66 return uuid2;
67 }
68 }
69
70 public static boolean usesJDKImpl() {
71 return jdk15createMethod != null;
72 }
73
74 static {
75 Method jdk15UUID = null;
76 try {
77 Class c = Class.forName("java.util.UUID");
78 jdk15UUID = c.getDeclaredMethod("randomUUID", new Class [] {});
79 } catch (Throwable t) {
80 logger.warn("JDK1.5+ UUID class not available, falling back to default implementation. " + t.getMessage());
81 }
82
83 jdk15createMethod = jdk15UUID;
84 }
85
86 public static void main(String args[]) {
87 for (int i = 0; i < 10; i++) {
88 System.out.println(UUID.getUUID());
89 }
90 }
91
92 }
93 |
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