1 /*
2 * Copyright 2005-2008 The Kuali Foundation
3 *
4 * Licensed under the Educational Community License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.opensource.org/licenses/ecl2.php
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.kuali.rice.kns.util;
17
18 import java.security.MessageDigest;
19 import java.security.NoSuchAlgorithmException;
20
21 import org.apache.ojb.broker.util.GUID;
22
23 /**
24 *
25 * This class wraps an OJB Guid so that it conforms to the format (and using the algorithm) described in
26 * RFC 4122 entitled " A Universally Unique IDentifier (UUID) URN Namespace"
27 */
28 public class Guid {
29
30 private final static char HYPHEN='-';
31 private final static String DIGITS="0123456789ABCDEF";
32 private String stringValue=null;
33 private GUID guid;
34
35 public Guid() {
36
37 guid = new GUID(); // This OJB class is deprecated; remove this line when we upgrade OJB
38
39
40 String guidString=guid.toString();
41 // this is roughly the prefered way with the new OJB GUIDFactory:
42 // String guidString=org.apache.ojb.broker.util.GUIDFactory.next();
43
44
45 MessageDigest sha;
46 try {
47 sha = MessageDigest.getInstance("SHA-1");
48 }
49 catch (NoSuchAlgorithmException e) {
50 throw new RuntimeException(e);
51 }
52 sha.update(guidString.getBytes());
53 byte[] hash=sha.digest();
54
55 StringBuffer result=new StringBuffer();
56 for (int i=0; i<hash.length; i++) {
57 result.append(toHex(hash[i]));
58 }
59
60 // hyphenate
61 for (int i=20; i>4; i-=4) {
62 result.insert(i,HYPHEN);
63 }
64
65 // truncate
66 result.delete(32,40);
67 stringValue=result.toString();
68 }
69
70 public static String toHex(byte b) {
71
72 int ub=b<0?b+256:b;
73
74 StringBuffer result=new StringBuffer(2);
75 result.append(DIGITS.charAt(ub/16));
76 result.append(DIGITS.charAt(ub%16));
77
78 return result.toString();
79 }
80
81 @Override
82 public String toString() {
83 return stringValue;
84 }
85
86 }