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Java > Open Source Codes > org > springframework > orm > hibernate3 > HibernateInterceptor


1 /*
2  * Copyright 2002-2006 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.springframework.orm.hibernate3;
18
19 import org.aopalliance.intercept.MethodInterceptor;
20 import org.aopalliance.intercept.MethodInvocation;
21 import org.hibernate.FlushMode;
22 import org.hibernate.HibernateException;
23 import org.hibernate.Session;
24
25 import org.springframework.transaction.support.TransactionSynchronizationManager;
26
27 /**
28  * This interceptor binds a new Hibernate Session to the thread before a method
29  * call, closing and removing it afterwards in case of any method outcome.
30  * If there already is a pre-bound Session (e.g. from HibernateTransactionManager,
31  * or from a surrounding Hibernate-intercepted method), the interceptor simply
32  * participates in it.
33  *
34  * <p>Application code must retrieve a Hibernate Session via the
35  * <code>SessionFactoryUtils.getSession</code> method or - preferably -
36  * Hibernate's own <code>SessionFactory.getCurrentSession()</code> method, to be
37  * able to detect a thread-bound Session. Typically, the code will look like as follows:
38  *
39  * <pre>
40  * public void doSomeDataAccessAction() {
41  * Session session = this.sessionFactory.getCurrentSession();
42  * ...
43  * // No need to close the Session or translate exceptions!
44  * }</pre>
45  *
46  * Note that this interceptor automatically translates HibernateExceptions,
47  * via delegating to the <code>SessionFactoryUtils.convertHibernateAccessException</code>
48  * method that converts them to exceptions that are compatible with the
49  * <code>org.springframework.dao</code> exception hierarchy (like HibernateTemplate does).
50  * This can be turned off if the raw exceptions are preferred.
51  *
52  * <p>This class can be considered a declarative alternative to HibernateTemplate's
53  * callback approach. The advantages are:
54  * <ul>
55  * <li>no anonymous classes necessary for callback implementations;
56  * <li>the possibility to throw any application exceptions from within data access code.
57  * </ul>
58  *
59  * <p>The drawback is the dependency on interceptor configuration. However, note
60  * that this interceptor is usually <i>not</i> necessary in scenarios where the
61  * data access code always executes within transactions. A transaction will always
62  * have a thread-bound Session in the first place, so adding this interceptor to the
63  * configuration just adds value when fine-tuning Session settings like the flush mode
64  * - or when relying on exception translation.
65  *
66  * @author Juergen Hoeller
67  * @since 1.2
68  * @see org.hibernate.SessionFactory#getCurrentSession()
69  * @see HibernateTransactionManager
70  * @see HibernateTemplate
71  */
72 public class HibernateInterceptor extends HibernateAccessor implements MethodInterceptor {
73
74     private boolean exceptionConversionEnabled = true;
75
76
77     /**
78      * Set whether to convert any HibernateException raised to a Spring DataAccessException,
79      * compatible with the <code>org.springframework.dao</code> exception hierarchy.
80      * <p>Default is "true". Turn this flag off to let the caller receive raw exceptions
81      * as-is, without any wrapping.
82      * @see org.springframework.dao.DataAccessException
83      */
84     public void setExceptionConversionEnabled(boolean exceptionConversionEnabled) {
85         this.exceptionConversionEnabled = exceptionConversionEnabled;
86     }
87
88
89     public Object JavaDoc invoke(MethodInvocation methodInvocation) throws Throwable JavaDoc {
90         Session session = getSession();
91         boolean existingTransaction = SessionFactoryUtils.isSessionTransactional(session, getSessionFactory());
92
93         if (existingTransaction) {
94             logger.debug("Found thread-bound Session for HibernateInterceptor");
95         }
96         else {
97             TransactionSynchronizationManager.bindResource(getSessionFactory(), new SessionHolder(session));
98         }
99
100         FlushMode previousFlushMode = null;
101         try {
102             previousFlushMode = applyFlushMode(session, existingTransaction);
103             enableFilters(session);
104             Object JavaDoc retVal = methodInvocation.proceed();
105             flushIfNecessary(session, existingTransaction);
106             return retVal;
107         }
108         catch (HibernateException ex) {
109             if (this.exceptionConversionEnabled) {
110                 throw convertHibernateAccessException(ex);
111             }
112             else {
113                 throw ex;
114             }
115         }
116         finally {
117             if (existingTransaction) {
118                 logger.debug("Not closing pre-bound Hibernate Session after HibernateInterceptor");
119                 disableFilters(session);
120                 if (previousFlushMode != null) {
121                     session.setFlushMode(previousFlushMode);
122                 }
123             }
124             else {
125                 TransactionSynchronizationManager.unbindResource(getSessionFactory());
126                 SessionFactoryUtils.closeSessionOrRegisterDeferredClose(session, getSessionFactory());
127             }
128         }
129     }
130
131     /**
132      * Return a Session for use by this interceptor.
133      * @see SessionFactoryUtils#getSession
134      */
135     protected Session getSession() {
136         return SessionFactoryUtils.getSession(
137                 getSessionFactory(), getEntityInterceptor(), getJdbcExceptionTranslator());
138     }
139
140 }
141
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