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Java > Open Source Codes > org > apache > geronimo > transaction > manager > XidFactoryImpl


1 /**
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 package org.apache.geronimo.transaction.manager;
19
20 import javax.transaction.xa.Xid JavaDoc;
21 import java.net.InetAddress JavaDoc;
22 import java.net.UnknownHostException JavaDoc;
23
24 /**
25  * Factory for transaction ids.
26  * The Xid is constructed of three parts:
27  * <ol><li>8 byte count (LSB first)</li>
28  * <li>4 byte system id</li>
29  * <li>4 or 16 byte IP address of host</li>
30  * <ol>
31  * @version $Rev: 476049 $ $Date: 2006-11-16 23:35:17 -0500 (Thu, 16 Nov 2006) $
32  * todo Should have a way of setting baseId
33  */
34 public class XidFactoryImpl implements XidFactory {
35     private final byte[] baseId = new byte[Xid.MAXGTRIDSIZE];
36     private long count = 1;
37
38     public XidFactoryImpl(byte[] tmId) {
39        System.arraycopy(tmId, 0, baseId, 8, tmId.length);
40     }
41
42     public XidFactoryImpl() {
43         byte[] hostid;
44         try {
45             hostid = InetAddress.getLocalHost().getAddress();
46         } catch (UnknownHostException JavaDoc e) {
47             hostid = new byte[]{127, 0, 0, 1};
48         }
49         int uid = System.identityHashCode(this);
50         baseId[8] = (byte) uid;
51         baseId[9] = (byte) (uid >>> 8);
52         baseId[10] = (byte) (uid >>> 16);
53         baseId[11] = (byte) (uid >>> 24);
54         System.arraycopy(hostid, 0, baseId, 12, hostid.length);
55     }
56
57     public Xid JavaDoc createXid() {
58         byte[] globalId = (byte[]) baseId.clone();
59         long id;
60         synchronized (this) {
61             id = count++;
62         }
63         globalId[0] = (byte) id;
64         globalId[1] = (byte) (id >>> 8);
65         globalId[2] = (byte) (id >>> 16);
66         globalId[3] = (byte) (id >>> 24);
67         globalId[4] = (byte) (id >>> 32);
68         globalId[5] = (byte) (id >>> 40);
69         globalId[6] = (byte) (id >>> 48);
70         globalId[7] = (byte) (id >>> 56);
71         return new XidImpl(globalId);
72     }
73
74     public Xid JavaDoc createBranch(Xid JavaDoc globalId, int branch) {
75         byte[] branchId = (byte[]) baseId.clone();
76         branchId[0] = (byte) branch;
77         branchId[1] = (byte) (branch >>> 8);
78         branchId[2] = (byte) (branch >>> 16);
79         branchId[3] = (byte) (branch >>> 24);
80         return new XidImpl(globalId, branchId);
81     }
82
83     public boolean matchesGlobalId(byte[] globalTransactionId) {
84         if (globalTransactionId.length != Xid.MAXGTRIDSIZE) {
85             return false;
86         }
87         for (int i = 8; i < globalTransactionId.length; i++) {
88             if (globalTransactionId[i] != baseId[i]) {
89                 return false;
90             }
91         }
92         return true;
93     }
94
95     public boolean matchesBranchId(byte[] branchQualifier) {
96         if (branchQualifier.length != Xid.MAXBQUALSIZE) {
97             return false;
98         }
99         for (int i = 8; i < branchQualifier.length; i++) {
100             if (branchQualifier[i] != baseId[i]) {
101                 return false;
102             }
103         }
104         return true;
105     }
106
107     public Xid JavaDoc recover(int formatId, byte[] globalTransactionid, byte[] branchQualifier) {
108         return new XidImpl(formatId, globalTransactionid, branchQualifier);
109     }
110
111 }
112
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