001: /*
002: * Copyright 2002-2007 the original author or authors.
003: *
004: * Licensed under the Apache License, Version 2.0 (the "License");
005: * you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at
007: *
008: * http://www.apache.org/licenses/LICENSE-2.0
009: *
010: * Unless required by applicable law or agreed to in writing, software
011: * distributed under the License is distributed on an "AS IS" BASIS,
012: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013: * See the License for the specific language governing permissions and
014: * limitations under the License.
015: */
016:
017: package org.springframework.orm.hibernate3;
018:
019: import org.aopalliance.intercept.MethodInterceptor;
020: import org.aopalliance.intercept.MethodInvocation;
021: import org.hibernate.FlushMode;
022: import org.hibernate.HibernateException;
023: import org.hibernate.Session;
024:
025: import org.springframework.transaction.support.TransactionSynchronizationManager;
026:
027: /**
028: * This interceptor binds a new Hibernate Session to the thread before a method
029: * call, closing and removing it afterwards in case of any method outcome.
030: * If there already is a pre-bound Session (e.g. from HibernateTransactionManager,
031: * or from a surrounding Hibernate-intercepted method), the interceptor simply
032: * participates in it.
033: *
034: * <p>Application code must retrieve a Hibernate Session via the
035: * <code>SessionFactoryUtils.getSession</code> method or - preferably -
036: * Hibernate's own <code>SessionFactory.getCurrentSession()</code> method, to be
037: * able to detect a thread-bound Session. Typically, the code will look like as follows:
038: *
039: * <pre>
040: * public void doSomeDataAccessAction() {
041: * Session session = this.sessionFactory.getCurrentSession();
042: * ...
043: * // No need to close the Session or translate exceptions!
044: * }</pre>
045: *
046: * Note that this interceptor automatically translates HibernateExceptions,
047: * via delegating to the <code>SessionFactoryUtils.convertHibernateAccessException</code>
048: * method that converts them to exceptions that are compatible with the
049: * <code>org.springframework.dao</code> exception hierarchy (like HibernateTemplate does).
050: * This can be turned off if the raw exceptions are preferred.
051: *
052: * <p>This class can be considered a declarative alternative to HibernateTemplate's
053: * callback approach. The advantages are:
054: * <ul>
055: * <li>no anonymous classes necessary for callback implementations;
056: * <li>the possibility to throw any application exceptions from within data access code.
057: * </ul>
058: *
059: * <p>The drawback is the dependency on interceptor configuration. However, note
060: * that this interceptor is usually <i>not</i> necessary in scenarios where the
061: * data access code always executes within transactions. A transaction will always
062: * have a thread-bound Session in the first place, so adding this interceptor to the
063: * configuration just adds value when fine-tuning Session settings like the flush mode
064: * - or when relying on exception translation.
065: *
066: * @author Juergen Hoeller
067: * @since 1.2
068: * @see org.hibernate.SessionFactory#getCurrentSession()
069: * @see HibernateTransactionManager
070: * @see HibernateTemplate
071: */
072: public class HibernateInterceptor extends HibernateAccessor implements
073: MethodInterceptor {
074:
075: private boolean exceptionConversionEnabled = true;
076:
077: /**
078: * Set whether to convert any HibernateException raised to a Spring DataAccessException,
079: * compatible with the <code>org.springframework.dao</code> exception hierarchy.
080: * <p>Default is "true". Turn this flag off to let the caller receive raw exceptions
081: * as-is, without any wrapping.
082: * @see org.springframework.dao.DataAccessException
083: */
084: public void setExceptionConversionEnabled(
085: boolean exceptionConversionEnabled) {
086: this .exceptionConversionEnabled = exceptionConversionEnabled;
087: }
088:
089: public Object invoke(MethodInvocation methodInvocation)
090: throws Throwable {
091: Session session = getSession();
092: SessionHolder sessionHolder = (SessionHolder) TransactionSynchronizationManager
093: .getResource(getSessionFactory());
094:
095: boolean existingTransaction = (sessionHolder != null && sessionHolder
096: .containsSession(session));
097: if (existingTransaction) {
098: logger
099: .debug("Found thread-bound Session for HibernateInterceptor");
100: } else {
101: if (sessionHolder != null) {
102: sessionHolder.addSession(session);
103: } else {
104: TransactionSynchronizationManager
105: .bindResource(getSessionFactory(),
106: new SessionHolder(session));
107: }
108: }
109:
110: FlushMode previousFlushMode = null;
111: try {
112: previousFlushMode = applyFlushMode(session,
113: existingTransaction);
114: enableFilters(session);
115: Object retVal = methodInvocation.proceed();
116: flushIfNecessary(session, existingTransaction);
117: return retVal;
118: } catch (HibernateException ex) {
119: if (this .exceptionConversionEnabled) {
120: throw convertHibernateAccessException(ex);
121: } else {
122: throw ex;
123: }
124: } finally {
125: if (existingTransaction) {
126: logger
127: .debug("Not closing pre-bound Hibernate Session after HibernateInterceptor");
128: disableFilters(session);
129: if (previousFlushMode != null) {
130: session.setFlushMode(previousFlushMode);
131: }
132: } else {
133: SessionFactoryUtils
134: .closeSessionOrRegisterDeferredClose(session,
135: getSessionFactory());
136: if (sessionHolder == null
137: || sessionHolder.doesNotHoldNonDefaultSession()) {
138: TransactionSynchronizationManager
139: .unbindResource(getSessionFactory());
140: }
141: }
142: }
143: }
144:
145: /**
146: * Return a Session for use by this interceptor.
147: * @see SessionFactoryUtils#getSession
148: */
149: protected Session getSession() {
150: return SessionFactoryUtils.getSession(getSessionFactory(),
151: getEntityInterceptor(), getJdbcExceptionTranslator());
152: }
153:
154: }
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