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


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 org.apache.ojb.odmg.TransactionImpl;
19 import org.apache.ojb.broker.util.configuration.Configuration;
20 import org.apache.ojb.broker.util.configuration.impl.OjbConfigurator;
21
22 import java.util.Collection JavaDoc;
23
24 /**
25  * The base class of all LockingStrategies. It provides the basic
26  * infrastructure to read and write locks to the persistent storage.
27  * @deprecated
28  * @author Thomas Mahler
29  */
30 public abstract class AbstractLockStrategy implements LockStrategy
31 {
32     /**
33      * the timeout for lock entries
34      */
35     public static long DEFAULT_LOCK_TIMEOUT = 30000;
36
37     /**
38      * the map holding all locks
39      */
40     private static LockMap lockMap = null;
41
42
43     public AbstractLockStrategy()
44     {
45         synchronized (AbstractLockStrategy.class)
46         {
47             if (lockMap == null)
48             {
49                 lockMap = LockMapFactory.getLockMap();
50                 Configuration conf = OjbConfigurator.getInstance().getConfigurationFor(null);
51                 DEFAULT_LOCK_TIMEOUT = conf.getInteger("LockTimeout", 60000);
52             }
53         }
54     }
55
56
57     /**
58      * returns the LockEntry for the Writer of object obj.
59      * If now writer exists, null is returned.
60      */
61     protected LockEntry getWriter(Object JavaDoc obj)
62     {
63         return lockMap.getWriter(obj);
64     }
65
66     /**
67      * returns a collection of Reader LockEntries for object obj.
68      * If now LockEntries could be found an empty Vector is returned.
69      */
70     protected Collection JavaDoc getReaders(Object JavaDoc obj)
71     {
72         return lockMap.getReaders(obj);
73     }
74
75     /**
76      * Add a reader lock entry for transaction tx on object obj
77      * to the persistent storage.
78      */
79     protected boolean addReader(TransactionImpl tx, Object JavaDoc obj)
80     {
81         return lockMap.addReader(tx, obj);
82     }
83
84     /**
85      * remove a reader lock entry for transaction tx on object obj
86      * from the persistent storage.
87      */
88     protected void removeReader(TransactionImpl tx, Object JavaDoc obj)
89     {
90         lockMap.removeReader(tx, obj);
91     }
92
93     /**
94      * remove a writer lock entry for transaction tx on object obj
95      * from the persistent storage.
96      */
97     protected void removeWriter(LockEntry writer)
98     {
99         lockMap.removeWriter(writer);
100     }
101
102
103     /**
104      * upgrade a reader lock entry for transaction tx on object obj
105      * and write it to the persistent storage.
106      */
107     protected boolean upgradeLock(LockEntry reader)
108     {
109         return lockMap.upgradeLock(reader);
110     }
111
112     /**
113      * generate a writer lock entry for transaction tx on object obj
114      * and write it to the persistent storage.
115      */
116     protected boolean setWriter(TransactionImpl tx, Object JavaDoc obj)
117     {
118         return lockMap.setWriter(tx, obj);
119     }
120
121     /**
122      * check if there is a reader lock entry for transaction tx on object obj
123      * in the persistent storage.
124      */
125     protected boolean hasReadLock(TransactionImpl tx, Object JavaDoc obj)
126     {
127         return lockMap.hasReadLock(tx, obj);
128     }
129
130 }
131
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