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Exposes JPA-style shared proxy instances through LocalSessionFactoryBean. Closes gh-7184pull/34146/merge
Juergen Hoeller
5 months ago
9 changed files with 424 additions and 73 deletions
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/* |
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* Copyright 2002-present the original author or authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* https://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package org.springframework.orm.jpa.hibernate; |
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import java.lang.reflect.InvocationHandler; |
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import java.lang.reflect.InvocationTargetException; |
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import java.lang.reflect.Method; |
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import java.lang.reflect.Proxy; |
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import java.util.function.Supplier; |
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import org.hibernate.Session; |
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import org.hibernate.SessionFactory; |
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import org.hibernate.StatelessSession; |
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import org.jspecify.annotations.Nullable; |
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/** |
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* Delegate for creating shareable {@link Session}/{@link StatelessSession} |
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* references for a given {@link SessionFactory}. |
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* |
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* <p>Typically used next to {@link LocalSessionFactoryBuilder}. Note that |
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* {@link LocalSessionFactoryBean} exposes shared {@link Session} as well |
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* as {@link StatelessSession} references for dependency injection already, |
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* avoiding the need to define separate beans for the shared sessions. |
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* |
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* @author Juergen Hoeller |
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* @since 7.0 |
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* @see LocalSessionFactoryBuilder |
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* @see LocalSessionFactoryBean |
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* @see org.springframework.orm.jpa.SharedEntityManagerCreator |
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*/ |
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public abstract class SharedSessionCreator { |
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/** |
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* Create a shared {@link Session} proxy for the given {@link SessionFactory}. |
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* <p>The returned instance behaves like {@link SessionFactory#getCurrentSession()} |
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* but without the manual get call, automatically delegating every {@link Session} |
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* method invocation to the current thread-bound transactional session instance. |
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* Designed to work with {@link HibernateTransactionManager} as well as JTA. |
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* <p>Alternatively, use {@link SessionFactory#getCurrentSession()} directly. |
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* @param sessionFactory the SessionFactory to build the Session proxy for |
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* @see SessionFactory#getCurrentSession() |
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*/ |
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public static Session createSharedSession(SessionFactory sessionFactory) { |
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return (Session) Proxy.newProxyInstance(SharedSessionCreator.class.getClassLoader(), |
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new Class<?>[] {Session.class}, |
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new SharedSessionInvocationHandler(sessionFactory, sessionFactory::getCurrentSession)); |
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} |
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/** |
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* Create a shared {@link StatelessSession} proxy for the given {@link SessionFactory}. |
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* <p>The returned instance automatically delegates every {@link StatelessSession} |
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* method invocation to the current thread-bound transactional session instance. |
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* On the first invocation within a new transaction, a {@link StatelessSession} |
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* will be opened for the current transactional JDBC Connection. |
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* <p>Works with {@link HibernateTransactionManager} (side by side with a |
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* thread-bound regular Session that drives the transaction) as well as |
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* {@link org.springframework.jdbc.support.JdbcTransactionManager} or |
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* {@link org.springframework.transaction.jta.JtaTransactionManager} |
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* (with a plain StatelessSession on top of a transactional JDBC Connection). |
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* <p>Alternatively, call {@link SpringSessionContext#currentStatelessSession} |
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* for every operation, avoiding the need for a proxy. |
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* @param sessionFactory the SessionFactory to build the StatelessSession proxy for |
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* @see SpringSessionContext#currentStatelessSession(SessionFactory) |
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*/ |
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public static StatelessSession createSharedStatelessSession(SessionFactory sessionFactory) { |
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return (StatelessSession) Proxy.newProxyInstance(SharedSessionCreator.class.getClassLoader(), |
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new Class<?>[] {StatelessSession.class}, |
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new SharedSessionInvocationHandler(sessionFactory, |
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() -> SpringSessionContext.currentStatelessSession(sessionFactory))); |
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} |
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private static class SharedSessionInvocationHandler implements InvocationHandler { |
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private final SessionFactory sessionFactory; |
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private final Supplier<Object> currentSessionSupplier; |
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public SharedSessionInvocationHandler(SessionFactory sessionFactory, Supplier<Object> currentSessionSupplier) { |
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this.sessionFactory = sessionFactory; |
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this.currentSessionSupplier = currentSessionSupplier; |
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} |
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@Override |
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public @Nullable Object invoke(Object proxy, Method method, Object[] args) throws Throwable { |
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switch (method.getName()) { |
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case "equals" -> { |
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// Only consider equal when proxies are identical.
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return (proxy == args[0]); |
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} |
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case "hashCode" -> { |
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// Use hashCode of EntityManager proxy.
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return hashCode(); |
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} |
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case "toString" -> { |
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// Deliver toString without touching a target EntityManager.
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return "Shared Session proxy for target factory [" + this.sessionFactory + "]"; |
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} |
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case "getSessionFactory", "getEntityManagerFactory" -> { |
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// JPA 2.0: return EntityManagerFactory without creating an EntityManager.
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return this.sessionFactory; |
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} |
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case "getCriteriaBuilder", "getMetamodel" -> { |
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// JPA 2.0: return EntityManagerFactory's CriteriaBuilder/Metamodel (avoid creation of EntityManager)
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try { |
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return SessionFactory.class.getMethod(method.getName()).invoke(this.sessionFactory); |
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} |
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catch (InvocationTargetException ex) { |
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throw ex.getTargetException(); |
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} |
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} |
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case "unwrap" -> { |
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// JPA 2.0: handle unwrap method - could be a proxy match.
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Class<?> targetClass = (Class<?>) args[0]; |
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if (targetClass != null && targetClass.isInstance(proxy)) { |
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return proxy; |
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} |
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} |
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case "isOpen" -> { |
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// Handle isOpen method: always return true.
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return true; |
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} |
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case "close" -> { |
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// Handle close method: suppress, not valid.
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return null; |
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} |
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case "getTransaction" -> { |
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throw new IllegalStateException( |
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"Not allowed to create transaction on shared EntityManager - " + |
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"use Spring transactions or EJB CMT instead"); |
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} |
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} |
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Object target = this.currentSessionSupplier.get(); |
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try { |
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return method.invoke(target, args); |
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} |
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catch (InvocationTargetException ex) { |
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throw ex.getTargetException(); |
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} |
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} |
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} |
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} |
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