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Java > Open Source Codes > org > apache > ojb > odmg > locking > ObjectLocks


1 package org.apache.ojb.odmg.locking;
2
3 /* Copyright 2002-2005 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 import java.util.Hashtable JavaDoc;
19
20 class ObjectLocks
21 {
22     private LockEntry writer;
23
24     private Hashtable JavaDoc readers;
25     
26     private long m_youngestReader = 0;
27
28     public LockEntry getWriter()
29     {
30         return writer;
31     }
32
33     public void setWriter(LockEntry writer)
34     {
35         this.writer = writer;
36     }
37
38     public Hashtable JavaDoc getReaders()
39     {
40         return readers;
41     }
42
43     public void addReader(LockEntry reader)
44     {
45         /**
46          * MBAIRD:
47          * we want to track the youngest reader so we can remove all readers at timeout
48          * if the youngestreader is older than the timeoutperiod.
49          */
50         if ((reader.getTimestamp() < m_youngestReader) || (m_youngestReader==0))
51         {
52             m_youngestReader = reader.getTimestamp();
53         }
54         this.readers.put(reader.getTransactionId(), reader);
55     }
56
57     public long getYoungestReader()
58     {
59         return m_youngestReader;
60     }
61     
62     public LockEntry getReader(String JavaDoc transactionId)
63     {
64         return (LockEntry) this.readers.get(transactionId);
65     }
66
67     ObjectLocks()
68     {
69         writer = null;
70         readers = new Hashtable JavaDoc();
71     }
72
73 }
74
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