1 /*
2  * Copyright 2002-2007 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 	 */
setExceptionConversionEnabled(boolean exceptionConversionEnabled)84 	public void setExceptionConversionEnabled(boolean exceptionConversionEnabled) {
85 		this.exceptionConversionEnabled = exceptionConversionEnabled;
86 	}
87 
88 
invoke(MethodInvocation methodInvocation)89 	public Object invoke(MethodInvocation methodInvocation) throws Throwable {
90 		Session session = getSession();
91 		SessionHolder sessionHolder =
92 				(SessionHolder) TransactionSynchronizationManager.getResource(getSessionFactory());
93 
94 		boolean existingTransaction = (sessionHolder != null && sessionHolder.containsSession(session));
95 		if (existingTransaction) {
96 			logger.debug("Found thread-bound Session for HibernateInterceptor");
97 		}
98 		else {
99 			if (sessionHolder != null) {
100 				sessionHolder.addSession(session);
101 			}
102 			else {
103 				TransactionSynchronizationManager.bindResource(getSessionFactory(), new SessionHolder(session));
104 			}
105 		}
106 
107 		FlushMode previousFlushMode = null;
108 		try {
109 			previousFlushMode = applyFlushMode(session, existingTransaction);
110 			enableFilters(session);
111 			Object retVal = methodInvocation.proceed();
112 			flushIfNecessary(session, existingTransaction);
113 			return retVal;
114 		}
115 		catch (HibernateException ex) {
116 			if (this.exceptionConversionEnabled) {
117 				throw convertHibernateAccessException(ex);
118 			}
119 			else {
120 				throw ex;
121 			}
122 		}
123 		finally {
124 			if (existingTransaction) {
125 				logger.debug("Not closing pre-bound Hibernate Session after HibernateInterceptor");
126 				disableFilters(session);
127 				if (previousFlushMode != null) {
128 					session.setFlushMode(previousFlushMode);
129 				}
130 			}
131 			else {
132 				SessionFactoryUtils.closeSessionOrRegisterDeferredClose(session, getSessionFactory());
133 				if (sessionHolder == null || sessionHolder.doesNotHoldNonDefaultSession()) {
134 					TransactionSynchronizationManager.unbindResource(getSessionFactory());
135 				}
136 			}
137 		}
138 	}
139 
140 	/**
141 	 * Return a Session for use by this interceptor.
142 	 * @see SessionFactoryUtils#getSession
143 	 */
getSession()144 	protected Session getSession() {
145 		return SessionFactoryUtils.getSession(
146 				getSessionFactory(), getEntityInterceptor(), getJdbcExceptionTranslator());
147 	}
148 
149 }
150