001: /*
002: * Copyright 2002-2006 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: boolean existingTransaction = SessionFactoryUtils
093: .isSessionTransactional(session, getSessionFactory());
094:
095: if (existingTransaction) {
096: logger
097: .debug("Found thread-bound Session for HibernateInterceptor");
098: } else {
099: TransactionSynchronizationManager.bindResource(
100: getSessionFactory(), new SessionHolder(session));
101: }
102:
103: FlushMode previousFlushMode = null;
104: try {
105: previousFlushMode = applyFlushMode(session,
106: existingTransaction);
107: enableFilters(session);
108: Object retVal = methodInvocation.proceed();
109: flushIfNecessary(session, existingTransaction);
110: return retVal;
111: } catch (HibernateException ex) {
112: if (this .exceptionConversionEnabled) {
113: throw convertHibernateAccessException(ex);
114: } else {
115: throw ex;
116: }
117: } finally {
118: if (existingTransaction) {
119: logger
120: .debug("Not closing pre-bound Hibernate Session after HibernateInterceptor");
121: disableFilters(session);
122: if (previousFlushMode != null) {
123: session.setFlushMode(previousFlushMode);
124: }
125: } else {
126: TransactionSynchronizationManager
127: .unbindResource(getSessionFactory());
128: SessionFactoryUtils
129: .closeSessionOrRegisterDeferredClose(session,
130: getSessionFactory());
131: }
132: }
133: }
134:
135: /**
136: * Return a Session for use by this interceptor.
137: * @see SessionFactoryUtils#getSession
138: */
139: protected Session getSession() {
140: return SessionFactoryUtils.getSession(getSessionFactory(),
141: getEntityInterceptor(), getJdbcExceptionTranslator());
142: }
143:
144: }
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