/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
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 * distributed under license by Red Hat Inc.
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 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
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 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
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 * You should have received a copy of the GNU Lesser General Public License
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package org.hibernate.proxy;

import java.io.Serializable;
import javax.naming.NamingException;

import org.hibernate.FlushMode;
import org.hibernate.HibernateException;
import org.hibernate.LazyInitializationException;
import org.hibernate.Session;
import org.hibernate.SessionException;
import org.hibernate.TransientObjectException;
import org.hibernate.engine.spi.EntityKey;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.internal.SessionFactoryRegistry;
import org.hibernate.persister.entity.EntityPersister;

import org.jboss.logging.Logger;

Convenience base class for lazy initialization handlers. Centralizes the basic plumbing of doing lazy initialization freeing subclasses to acts as essentially adapters to their intended entity mode and/or proxy generation strategy.
Author:Gavin King
/** * Convenience base class for lazy initialization handlers. Centralizes the basic plumbing of doing lazy * initialization freeing subclasses to acts as essentially adapters to their intended entity mode and/or * proxy generation strategy. * * @author Gavin King */
public abstract class AbstractLazyInitializer implements LazyInitializer { private static final Logger log = Logger.getLogger( AbstractLazyInitializer.class ); private String entityName; private Serializable id; private Object target; private boolean initialized; private boolean readOnly; private boolean unwrap; private transient SessionImplementor session; private Boolean readOnlyBeforeAttachedToSession; private String sessionFactoryUuid; private boolean allowLoadOutsideTransaction;
For serialization from the non-pojo initializers (HHH-3309)
/** * For serialization from the non-pojo initializers (HHH-3309) */
protected AbstractLazyInitializer() { }
Main constructor.
Params:
  • entityName – The name of the entity being proxied.
  • id – The identifier of the entity being proxied.
  • session – The session owning the proxy.
/** * Main constructor. * * @param entityName The name of the entity being proxied. * @param id The identifier of the entity being proxied. * @param session The session owning the proxy. */
protected AbstractLazyInitializer(String entityName, Serializable id, SessionImplementor session) { this.entityName = entityName; this.id = id; // initialize other fields depending on session state if ( session == null ) { unsetSession(); } else { setSession( session ); } } @Override public final String getEntityName() { return entityName; } @Override public final Serializable getIdentifier() { return id; } @Override public final void setIdentifier(Serializable id) { this.id = id; } @Override public final boolean isUninitialized() { return !initialized; } @Override public final SessionImplementor getSession() { return session; } @Override public final void setSession(SessionImplementor s) throws HibernateException { if ( s != session ) { // check for s == null first, since it is least expensive if ( s == null ) { unsetSession(); } else if ( isConnectedToSession() ) { //TODO: perhaps this should be some other RuntimeException... throw new HibernateException( "illegally attempted to associate a proxy with two open Sessions" ); } else { // s != null session = s; if ( readOnlyBeforeAttachedToSession == null ) { // use the default read-only/modifiable setting final EntityPersister persister = s.getFactory().getEntityPersister( entityName ); setReadOnly( s.getPersistenceContext().isDefaultReadOnly() || !persister.isMutable() ); } else { // use the read-only/modifiable setting indicated during deserialization setReadOnly( readOnlyBeforeAttachedToSession ); readOnlyBeforeAttachedToSession = null; } } } } private static EntityKey generateEntityKeyOrNull(Serializable id, SessionImplementor s, String entityName) { if ( id == null || s == null || entityName == null ) { return null; } return s.generateEntityKey( id, s.getFactory().getEntityPersister( entityName ) ); } @Override public final void unsetSession() { prepareForPossibleLoadingOutsideTransaction(); session = null; readOnly = false; readOnlyBeforeAttachedToSession = null; } @Override public final void initialize() throws HibernateException { if ( !initialized ) { if ( allowLoadOutsideTransaction ) { permissiveInitialization(); } else if ( session == null ) { throw new LazyInitializationException( "could not initialize proxy - no Session" ); } else if ( !session.isOpen() ) { throw new LazyInitializationException( "could not initialize proxy - the owning Session was closed" ); } else if ( !session.isConnected() ) { throw new LazyInitializationException( "could not initialize proxy - the owning Session is disconnected" ); } else { target = session.immediateLoad( entityName, id ); initialized = true; checkTargetState(); } } else { checkTargetState(); } } protected void permissiveInitialization() { if ( session == null ) { //we have a detached collection thats set to null, reattach if ( sessionFactoryUuid == null ) { throw new LazyInitializationException( "could not initialize proxy - no Session" ); } try { SessionFactoryImplementor sf = (SessionFactoryImplementor) SessionFactoryRegistry.INSTANCE.getSessionFactory( sessionFactoryUuid ); SessionImplementor session = (SessionImplementor) sf.openSession(); session.getPersistenceContext().setDefaultReadOnly( true ); session.setFlushMode( FlushMode.MANUAL ); boolean isJTA = session.getTransactionCoordinator() .getTransactionContext().getTransactionEnvironment() .getTransactionFactory() .compatibleWithJtaSynchronization(); if ( !isJTA ) { // Explicitly handle the transactions only if we're not in // a JTA environment. A lazy loading temporary session can // be created even if a current session and transaction are // open (ex: session.clear() was used). We must prevent // multiple transactions. ( ( Session) session ).beginTransaction(); } try { target = session.immediateLoad( entityName, id ); } finally { // make sure the just opened temp session gets closed! try { if ( !isJTA ) { ( ( Session) session ).getTransaction().commit(); } ( (Session) session ).close(); } catch (Exception e) { log.warn( "Unable to close temporary session used to load lazy proxy associated to no session" ); } } initialized = true; checkTargetState(); } catch (Exception e) { e.printStackTrace(); throw new LazyInitializationException( e.getMessage() ); } } else if ( session.isOpen() && session.isConnected() ) { target = session.immediateLoad( entityName, id ); initialized = true; checkTargetState(); } else { throw new LazyInitializationException( "could not initialize proxy - Session was closed or disced" ); } } protected void prepareForPossibleLoadingOutsideTransaction() { if ( session != null ) { allowLoadOutsideTransaction = session.getFactory().getSettings().isInitializeLazyStateOutsideTransactionsEnabled(); if ( allowLoadOutsideTransaction && sessionFactoryUuid == null ) { try { sessionFactoryUuid = (String) session.getFactory().getReference().get( "uuid" ).getContent(); } catch (NamingException e) { //not much we can do if this fails... } } } } private void checkTargetState() { if ( !unwrap ) { if ( target == null ) { getSession().getFactory().getEntityNotFoundDelegate().handleEntityNotFound( entityName, id ); } } }
Getter for property 'connectedToSession'.
Returns:Value for property 'connectedToSession'.
/** * Getter for property 'connectedToSession'. * * @return Value for property 'connectedToSession'. */
protected final boolean isConnectedToSession() { return getProxyOrNull() != null; } private Object getProxyOrNull() { final EntityKey entityKey = generateEntityKeyOrNull( getIdentifier(), session, getEntityName() ); if ( entityKey != null && session != null && session.isOpen() ) { return session.getPersistenceContext().getProxy( entityKey ); } return null; } @Override public final Object getImplementation() { initialize(); return target; } @Override public final void setImplementation(Object target) { this.target = target; initialized = true; } @Override public final Object getImplementation(SessionImplementor s) throws HibernateException { final EntityKey entityKey = generateEntityKeyOrNull( getIdentifier(), s, getEntityName() ); return (entityKey == null ? null : s.getPersistenceContext().getEntity( entityKey )); }
Getter for property 'target'.

Same as getImplementation() except that this method will not force initialization.
Returns:Value for property 'target'.
/** * Getter for property 'target'. * <p/> * Same as {@link #getImplementation()} except that this method will not force initialization. * * @return Value for property 'target'. */
protected final Object getTarget() { return target; } @Override public final boolean isReadOnlySettingAvailable() { return (session != null && !session.isClosed()); } private void errorIfReadOnlySettingNotAvailable() { if ( session == null ) { throw new TransientObjectException( "Proxy is detached (i.e, session is null). The read-only/modifiable setting is only accessible when the proxy is associated with an open session." ); } if ( session.isClosed() ) { throw new SessionException( "Session is closed. The read-only/modifiable setting is only accessible when the proxy is associated with an open session." ); } } @Override public final boolean isReadOnly() { errorIfReadOnlySettingNotAvailable(); return readOnly; } @Override public final void setReadOnly(boolean readOnly) { errorIfReadOnlySettingNotAvailable(); // only update if readOnly is different from current setting if ( this.readOnly != readOnly ) { final EntityPersister persister = session.getFactory().getEntityPersister( entityName ); if ( !persister.isMutable() && !readOnly ) { throw new IllegalStateException( "cannot make proxies for immutable entities modifiable" ); } this.readOnly = readOnly; if ( initialized ) { EntityKey key = generateEntityKeyOrNull( getIdentifier(), session, getEntityName() ); if ( key != null && session.getPersistenceContext().containsEntity( key ) ) { session.getPersistenceContext().setReadOnly( target, readOnly ); } } } }
Get the read-only/modifiable setting that should be put in affect when it is attached to a session.

This method should only be called during serialization when read-only/modifiable setting is not available (i.e., isReadOnlySettingAvailable() == false)
Throws:
Returns:null, if the default setting should be used; true, for read-only; false, for modifiable
/** * Get the read-only/modifiable setting that should be put in affect when it is * attached to a session. * <p/> * This method should only be called during serialization when read-only/modifiable setting * is not available (i.e., isReadOnlySettingAvailable() == false) * * @return null, if the default setting should be used; * true, for read-only; * false, for modifiable * * @throws IllegalStateException if isReadOnlySettingAvailable() == true */
protected final Boolean isReadOnlyBeforeAttachedToSession() { if ( isReadOnlySettingAvailable() ) { throw new IllegalStateException( "Cannot call isReadOnlyBeforeAttachedToSession when isReadOnlySettingAvailable == true" ); } return readOnlyBeforeAttachedToSession; }
Set the read-only/modifiable setting that should be put in affect when it is attached to a session.

This method should only be called during deserialization, before associating the proxy with a session.
Throws:
@paramreadOnlyBeforeAttachedToSession, the read-only/modifiable setting to use when associated with a session; null indicates that the default should be used.
/** * Set the read-only/modifiable setting that should be put in affect when it is * attached to a session. * <p/> * This method should only be called during deserialization, before associating * the proxy with a session. * * @param readOnlyBeforeAttachedToSession, the read-only/modifiable setting to use when * associated with a session; null indicates that the default should be used. * * @throws IllegalStateException if isReadOnlySettingAvailable() == true */
/* package-private */ final void setReadOnlyBeforeAttachedToSession(Boolean readOnlyBeforeAttachedToSession) { if ( isReadOnlySettingAvailable() ) { throw new IllegalStateException( "Cannot call setReadOnlyBeforeAttachedToSession when isReadOnlySettingAvailable == true" ); } this.readOnlyBeforeAttachedToSession = readOnlyBeforeAttachedToSession; } @Override public boolean isUnwrap() { return unwrap; } @Override public void setUnwrap(boolean unwrap) { this.unwrap = unwrap; } }