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1   /**
2    *
3    * Copyright 2003-2004 The Apache Software Foundation
4    *
5    *  Licensed under the Apache License, Version 2.0 (the "License");
6    *  you may not use this file except in compliance with the License.
7    *  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 java.io.Serializable;
21  import java.util.Arrays;
22  import javax.transaction.xa.Xid;
23  
24  /**
25   * Unique id for a transaction.
26   *
27   * @version $Rev: 355877 $ $Date: 2005-12-10 18:48:27 -0800 (Sat, 10 Dec 2005) $
28   */
29  public class XidImpl implements Xid, Serializable {
30      private static int FORMAT_ID = 0x4765526f;  // Gero
31      private final int formatId;
32      private final byte[] globalId;
33      private final byte[] branchId;
34      private int hash;   //apparently never used by our code, so don't compute it.
35  
36      /**
37       * Constructor taking a global id (for the main transaction)
38       * @param globalId the global transaction id
39       */
40      public XidImpl(byte[] globalId) {
41          this.formatId = FORMAT_ID;
42          this.globalId = globalId;
43          //this.hash = hash(0, globalId);
44          branchId = new byte[Xid.MAXBQUALSIZE];
45      }
46  
47      /**
48       * Constructor for a branch id
49       * @param global the xid of the global transaction this branch belongs to
50       * @param branch the branch id
51       */
52      public XidImpl(Xid global, byte[] branch) {
53          this.formatId = FORMAT_ID;
54          //int hash;
55          if (global instanceof XidImpl) {
56              globalId = ((XidImpl) global).globalId;
57              //hash = ((XidImpl) global).hash;
58          } else {
59              globalId = global.getGlobalTransactionId();
60              //hash = hash(0, globalId);
61          }
62          branchId = branch;
63          //this.hash = hash(hash, branchId);
64      }
65  
66      public XidImpl(int formatId, byte[] globalId, byte[] branchId) {
67          this.formatId = formatId;
68          this.globalId = globalId;
69          this.branchId = branchId;
70      }
71  
72      private int hash(int hash, byte[] id) {
73          for (int i = 0; i < id.length; i++) {
74              hash = (hash * 37) + id[i];
75          }
76          return hash;
77      }
78  
79      public int getFormatId() {
80          return formatId;
81      }
82  
83      public byte[] getGlobalTransactionId() {
84          return (byte[]) globalId.clone();
85      }
86  
87      public byte[] getBranchQualifier() {
88          return (byte[]) branchId.clone();
89      }
90  
91      public boolean equals(Object obj) {
92          if (obj instanceof XidImpl == false) {
93              return false;
94          }
95          XidImpl other = (XidImpl) obj;
96          return formatId == other.formatId
97                  && Arrays.equals(globalId, other.globalId)
98                  && Arrays.equals(branchId, other.branchId);
99      }
100 
101     public int hashCode() {
102         if (hash == 0) {
103             hash = hash(hash(0, globalId), branchId);
104         }
105         return hash;
106     }
107 
108     public String toString() {
109         StringBuffer s = new StringBuffer();
110         s.append("[globalId=");
111         for (int i = 0; i < globalId.length; i++) {
112             s.append(Integer.toHexString(globalId[i]));
113         }
114         s.append(",branchId=");
115         for (int i = 0; i < branchId.length; i++) {
116             s.append(Integer.toHexString(branchId[i]));
117         }
118         s.append("]");
119         return s.toString();
120     }
121 }