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Java > Open Source Codes > org > apache > ojb > odmg > PBCapsule


1 package org.apache.ojb.odmg;
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.broker.OJBRuntimeException;
19 import org.apache.ojb.broker.PBFactoryException;
20 import org.apache.ojb.broker.PBKey;
21 import org.apache.ojb.broker.PersistenceBroker;
22 import org.apache.ojb.broker.PersistenceBrokerFactory;
23 import org.apache.ojb.broker.util.logging.Logger;
24 import org.apache.ojb.broker.util.logging.LoggerFactory;
25 import org.odmg.Transaction;
26
27 public final class PBCapsule
28 {
29     private static Logger log = LoggerFactory.getLogger(PBCapsule.class);
30
31     PersistenceBroker broker;
32     PBKey pbKey;
33     Transaction tx;
34     boolean needsTxCommit = false;
35     boolean needsPBCommit = false;
36     boolean isIlleagal = false;
37
38     public PBCapsule(final PBKey pbKey, final Transaction tx)
39     {
40         this.tx = tx;
41         this.pbKey = pbKey;
42         prepare();
43     }
44
45     public PersistenceBroker getBroker()
46     {
47         if(isIlleagal) throw new OJBRuntimeException("You could not reuse PBCapsule after destroy");
48         return broker;
49     }
50
51     private void prepare()
52     {
53         if(isIlleagal) throw new OJBRuntimeException("You could not reuse PBCapsule after destroy");
54         // we allow queries even if no ODMG transaction is running.
55 // thus we use direct access to PBF via the given PBKey to
56 // get a PB instance
57 if (tx == null)
58         {
59             if (log.isDebugEnabled())
60                 log.debug("No running transaction found, try to get " +
61                         "PersistenceBroker instance via PBKey " + pbKey);
62             broker = obtainBroker();
63             // begin tx on the PB instance
64 if (!broker.isInTransaction())
65             {
66                 broker.beginTransaction();
67                 needsPBCommit = true;
68             }
69         }
70         else
71         {
72             // we allow to work with unopened transactions.
73 // we assume that such a tx is to be closed after performing the query
74 if (!tx.isOpen())
75             {
76                 tx.begin();
77                 needsTxCommit = true;
78             }
79             // obtain a broker instance from the current transaction
80 broker = ((HasBroker) tx).getBroker();
81         }
82     }
83
84     public void destroy()
85     {
86         if (needsTxCommit)
87         {
88             if (log.isDebugEnabled()) log.debug("Indicated to commit tx");
89             tx.commit();
90         }
91         else if (needsPBCommit)
92         {
93             if (log.isDebugEnabled()) log.debug("Indicated to commit PersistenceBroker");
94             try
95             {
96                 broker.commitTransaction();
97             }
98             finally
99             {
100                 if (broker != null) broker.close();
101             }
102         }
103         isIlleagal = true;
104         needsTxCommit = false;
105         needsPBCommit = false;
106     }
107
108     /**
109      * Used to get PB, when no tx is running.
110      */
111     private PersistenceBroker obtainBroker()
112     {
113         PersistenceBroker _broker;
114         try
115         {
116             if (pbKey == null)
117             {
118                 //throw new OJBRuntimeException("Not possible to do action, cause no tx runnning and no PBKey is set");
119 log.warn("No tx runnning and PBKey is null, try to use the default PB");
120                 _broker = PersistenceBrokerFactory.defaultPersistenceBroker();
121             }
122             else
123             {
124                 _broker = PersistenceBrokerFactory.createPersistenceBroker(pbKey);
125             }
126         }
127         catch (PBFactoryException e)
128         {
129             log.error("Could not obtain PB for PBKey " + pbKey, e);
130             throw new OJBRuntimeException("Unexpected micro-kernel exception", e);
131         }
132         return _broker;
133     }
134 }
135
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