ExternalXid


1   /**
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3    * ("Software"), with or without modification, are permitted provided
4    * that the following conditions are met:
5    *
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14   *
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21   *    nor may "Exolab" appear in their names without prior written
22   *    permission of Exoffice Technologies. Exolab is a registered
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25   * 5. Due credit should be given to the Exolab Project
26   *    (http://www.exolab.org/).
27   *
28   * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29   * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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32   * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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37   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39   * OF THE POSSIBILITY OF SUCH DAMAGE.
40   *
41   * Copyright 2002-2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42   *
43   *
44   * $Id: ExternalXid.java,v 1.1 2004/11/26 01:51:01 tanderson Exp $
45   *
46   * Date         Author  Changes
47   * 24/01/2002   jima    Created
48   */
49  package org.exolab.jms.tranlog;
50  
51  import java.io.Externalizable  ;
52  import java.io.IOException  ;
53  import java.io.ObjectInput  ;
54  import java.io.ObjectOutput  ;
55  
56  import javax.transaction.xa.Xid  ;
57  
58  
59  /**
60   * This class maps an external XID that is set in the transaction manager.
61   * It needs to do this so that it can use it internally.
62   *
63   * @version     $Revision: 1.1 $ $Date: 2004/11/26 01:51:01 $
64   * @author      <a HREF="mailto:jima@exoffice.com">Jim Alateras</a>
65   * @see         javax.transaction.xa.Xid
66   */
67  public final class ExternalXid
68      implements Xid  , Externalizable   {
69  
70      /**
71       * This is the unique id used to identify the version of the class
72       * for the purpose of Serialization
73       */
74      static final long serialVersionUID = 1;
75  
76      /**
77       * Efficient mapping from 4 bit value to lower case hexadecimal digit.
78       * gobbled from Tyrex imple
79       */
80      protected final static char[] HEX_DIGITS = new char[]{'0', '1', '2', '3', '4', '5', '6', '7',
81                                                            '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
82  
83      /**
84       * The format identifier of the distributed transaction identifier
85       */
86      private int _formatId;
87  
88      /**
89       * The array of bytes corresponding to the global transaction identifier
90       * part of the XID.
91       */
92      private byte[] _global;
93  
94      /**
95       * The array of bytes corresponding to the branch qualifier
96       * part of the XID.
97       */
98      private byte[] _branch;
99  
100     /**
101      * Cache a trnasient instance of the stringified version of the xid
102      */
103     private transient String   _string = null;
104 
105 
106     /**
107      * Default constructor for Serialization
108      */
109     public ExternalXid() {
110     }
111 
112     /**
113      * Create an instance of this class using the specified XID. This
114      * will always create a new instance and copy the format id, global
115      * transaction id and branch qualifier id to the new instance
116      *
117      * @param xid - the xid to use
118      */
119     public ExternalXid(Xid   xid) {
120         this(xid.getFormatId(), xid.getGlobalTransactionId(),
121             xid.getBranchQualifier());
122     }
123 
124     /**
125      * Create an insrance of this class using the specified format id,
126      * global transaction id and the branch qualifier.
127      *
128      * @param formatId - the format identifier
129      * @param global - the global transaction identifier
130      * @param branch - the branch qualifier
131      */
132     public ExternalXid(int formatId, byte[] global, byte[] branch) {
133         _formatId = formatId;
134 
135         // assign the global transaction identifier
136         if ((global == null) ||
137             (global.length == 0)) {
138             _global = new byte[0];
139         } else {
140             _global = new byte[global.length];
141             System.arraycopy(global, 0, _global, 0, global.length);
142         }
143 
144         // assign the branch qualifier
145         if ((branch == null) ||
146             (branch.length == 0)) {
147             _branch = new byte[0];
148         } else {
149             _branch = new byte[branch.length];
150             System.arraycopy(branch, 0, _branch, 0, branch.length);
151         }
152     }
153 
154     // implementation of Xid.getFormatId
155     public int getFormatId() {
156         return _formatId;
157     }
158 
159     // implementation of Xid.getFormatId
160     public byte[] getGlobalTransactionId() {
161         return _global;
162     }
163 
164     // implementation of Xid.getFormatId
165     public byte[] getBranchQualifier() {
166         return _branch;
167     }
168 
169     /**
170      * Returns the global transaction identifier in the form of
171      * exid://formatId.global.branch
172      *
173      * @return String
174      */
175     public String   toString() {
176 
177         if (_string == null) {
178             StringBuffer   buffer = new StringBuffer  ("xid://");
179             buffer.append(HEX_DIGITS[(int) ((_formatId >> 28) & 0x0F)]);
180             buffer.append(HEX_DIGITS[(int) ((_formatId >> 24) & 0x0F)]);
181             buffer.append(HEX_DIGITS[(int) ((_formatId >> 20) & 0x0F)]);
182             buffer.append(HEX_DIGITS[(int) ((_formatId >> 16) & 0x0F)]);
183             buffer.append(HEX_DIGITS[(int) ((_formatId >> 12) & 0x0F)]);
184             buffer.append(HEX_DIGITS[(int) ((_formatId >> 8) & 0x0F)]);
185             buffer.append(HEX_DIGITS[(int) ((_formatId >> 4) & 0x0F)]);
186             buffer.append(HEX_DIGITS[(int) (_formatId & 0x0F)]);
187             buffer.append('-');
188             if (_global != null && _global.length > 0) {
189                 for (int i = _global.length; i-- > 0;) {
190                     buffer.append(HEX_DIGITS[(_global[i] & 0xF0) >> 4]);
191                     buffer.append(HEX_DIGITS[(_global[i] & 0x0F)]);
192                 }
193             }
194             buffer.append('-');
195             if (_branch != null && _branch.length > 0) {
196                 for (int i = _branch.length; i-- > 0;) {
197                     buffer.append(HEX_DIGITS[(_branch[i] & 0xF0) >> 4]);
198                     buffer.append(HEX_DIGITS[(_branch[i] & 0x0F)]);
199                 }
200             }
201             _string = buffer.toString();
202         }
203 
204         return _string;
205     }
206 
207     // override implementation of Object.hashCode
208     public int hashCode() {
209         return toString().hashCode();
210     }
211 
212     // override implementation of Object.equals
213     public boolean equals(Object   obj) {
214 
215         if (obj == this) {
216             return true;
217         }
218 
219         if (obj instanceof ExternalXid) {
220 
221             Xid   xid = (Xid  ) obj;
222             // compare format ids
223             if (xid.getFormatId() != _formatId) {
224                 return false;
225             }
226 
227             // compare global transaction id
228             byte[] global = xid.getGlobalTransactionId();
229             if ((global == null) ||
230                 (global.length == 0)) {
231                 if ((_global != null) ||
232                     (_global.length != 0)) {
233                     return false;
234                 }
235             } else {
236                 if (global.length != _global.length) {
237                     return false;
238                 }
239 
240                 for (int index = 0; index < global.length; index++) {
241                     if (global[index] != _global[index]) {
242                         return false;
243                     }
244                 }
245             }
246 
247             // compare branch qualifier
248             byte[] branch = xid.getBranchQualifier();
249             if ((branch == null) ||
250                 (branch.length == 0)) {
251                 if ((_branch != null) ||
252                     (_branch.length != 0)) {
253                     return false;
254                 }
255             } else {
256                 if (branch.length != _branch.length) {
257                     return false;
258                 }
259 
260                 for (int index = 0; index < branch.length; index++) {
261                     if (branch[index] != _branch[index]) {
262                         return false;
263                     }
264                 }
265             }
266             return true;
267         }
268 
269         return false;
270     }
271 
272     // implementation of Externalizable.writeExternal
273     public void writeExternal(ObjectOutput   stream)
274         throws IOException   {
275         stream.writeLong(serialVersionUID);
276         stream.writeInt(_formatId);
277 
278         stream.writeInt(_global.length);
279         stream.write(_global);
280 
281         stream.writeInt(_branch.length);
282         stream.write(_branch);
283 
284     }
285 
286     // implementation of Externalizable.writeExternal
287     public void readExternal(ObjectInput   stream)
288         throws IOException  , ClassNotFoundException   {
289         long version = stream.readLong();
290 
291         if (version == serialVersionUID) {
292             _formatId = stream.readInt();
293 
294             _global = new byte[stream.readInt()];
295             stream.read(_global);
296 
297             _branch = new byte[stream.readInt()];
298             stream.read(_branch);
299 
300         } else {
301             throw new IOException  ("No support for ExternalXid " +
302                 "with version " + version);
303         }
304     }
305 }
306
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