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Java > Open Source Codes > org > apache > ojb > broker > util > sequence > SequenceManagerFactory


1 package org.apache.ojb.broker.util.sequence;
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.PersistenceBroker;
19 import org.apache.ojb.broker.PersistenceBrokerException;
20 import org.apache.ojb.broker.metadata.SequenceDescriptor;
21 import org.apache.ojb.broker.util.ClassHelper;
22 import org.apache.ojb.broker.util.logging.Logger;
23 import org.apache.ojb.broker.util.logging.LoggerFactory;
24
25 /**
26  * Threadsafe factory class, creates <code>SequenceManager</code> instances.
27  * The implementation class is configured by the OJB.properties file.
28  */
29 public class SequenceManagerFactory
30 {
31     private static Logger log = LoggerFactory.getLogger(SequenceManagerFactory.class);
32     private static SequenceManagerFactory singleton;
33
34     private Class JavaDoc defaultSeqManagerClass;
35
36     public SequenceManagerFactory()
37     {
38         defaultSeqManagerClass = SequenceManagerHighLowImpl.class;
39         if(log.isDebugEnabled()) log.debug("Default sequence manager class was " + defaultSeqManagerClass.getName());
40     }
41
42     public synchronized static SequenceManager getSequenceManager(PersistenceBroker broker)
43     {
44         if (singleton == null)
45         {
46             singleton = new SequenceManagerFactory();
47         }
48         return singleton.createNewSequenceManager(broker);
49     }
50
51     private SequenceManager createNewSequenceManager(PersistenceBroker broker)
52     {
53         synchronized (singleton)
54         {
55             if (log.isDebugEnabled()) log.debug("create new sequence manager for broker " + broker);
56             try
57             {
58                 // first we use seqMan defined in the OJB.properties
59 Class JavaDoc seqManClass = defaultSeqManagerClass;
60                 SequenceDescriptor sd = broker.serviceConnectionManager().getConnectionDescriptor().getSequenceDescriptor();
61                 if (sd != null && sd.getSequenceManagerClass() != null)
62                 {
63                     // if a seqMan was defined in repository, use that
64 seqManClass = sd.getSequenceManagerClass();
65                     if (log.isDebugEnabled())
66                     {
67                         log.debug("Jdbc-Connection-Descriptor '" +
68                                 broker.serviceConnectionManager().getConnectionDescriptor().getJcdAlias() +
69                                 "' use sequence manager: " + seqManClass);
70                     }
71                 }
72                 return (SequenceManager) ClassHelper.newInstance(seqManClass, PersistenceBroker.class, broker);
73             }
74             catch (Exception JavaDoc ex)
75             {
76                 log.error("Could not create sequence manager for broker " + broker, ex);
77                 throw new PersistenceBrokerException(ex);
78             }
79         }
80     }
81 }
82
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