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/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* 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.
*
* 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
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.event.def;
import java.io.Serializable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.NonUniqueObjectException;
import org.hibernate.PersistentObjectException;
import org.hibernate.TypeMismatchException;
import org.hibernate.EntityMode;
import org.hibernate.cache.CacheKey;
import org.hibernate.cache.access.SoftLock;
import org.hibernate.cache.entry.CacheEntry;
import org.hibernate.engine.EntityEntry;
import org.hibernate.engine.EntityKey;
import org.hibernate.engine.PersistenceContext;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.engine.Status;
import org.hibernate.engine.TwoPhaseLoad;
import org.hibernate.engine.Versioning;
import org.hibernate.event.EventSource;
import org.hibernate.event.LoadEvent;
import org.hibernate.event.LoadEventListener;
import org.hibernate.event.PostLoadEvent;
import org.hibernate.event.PostLoadEventListener;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.pretty.MessageHelper;
import org.hibernate.proxy.HibernateProxy;
import org.hibernate.proxy.LazyInitializer;
import org.hibernate.type.EmbeddedComponentType;
import org.hibernate.type.EntityType;
import org.hibernate.type.Type;
import org.hibernate.type.TypeFactory;
/**
* Defines the default load event listeners used by hibernate for loading entities
* in response to generated load events.
*
* @author Steve Ebersole
*/
public class DefaultLoadEventListener extends AbstractLockUpgradeEventListener implements LoadEventListener {
public static final Object REMOVED_ENTITY_MARKER = new Object();
public static final Object INCONSISTENT_RTN_CLASS_MARKER = new Object();
public static final LockMode DEFAULT_LOCK_MODE = LockMode.NONE;
private static final Logger log = LoggerFactory.getLogger(DefaultLoadEventListener.class);
/**
* Handle the given load event.
*
* @param event The load event to be handled.
* @throws HibernateException
*/
public void onLoad(LoadEvent event, LoadEventListener.LoadType loadType) throws HibernateException {
final SessionImplementor source = event.getSession();
EntityPersister persister;
if ( event.getInstanceToLoad() != null ) {
persister = source.getEntityPersister( null, event.getInstanceToLoad() ); //the load() which takes an entity does not pass an entityName
event.setEntityClassName( event.getInstanceToLoad().getClass().getName() );
}
else {
persister = source.getFactory().getEntityPersister( event.getEntityClassName() );
}
if ( persister == null ) {
throw new HibernateException(
"Unable to locate persister: " +
event.getEntityClassName()
);
}
if ( persister.getIdentifierType().isComponentType() && EntityMode.DOM4J == event.getSession().getEntityMode() ) {
// skip this check for composite-ids relating to dom4j entity-mode;
// alternatively, we could add a check to make sure the incoming id value is
// an instance of Element...
}
else {
Class idClass = persister.getIdentifierType().getReturnedClass();
if ( idClass != null && ! idClass.isInstance( event.getEntityId() ) ) {
// we may have the kooky jpa requirement of allowing find-by-id where
// "id" is the "simple pk value" of a dependent objects parent. This
// is part of its generally goofy "derived identity" "feature"
if ( persister.getEntityMetamodel().getIdentifierProperty().isEmbedded() ) {
final EmbeddedComponentType dependentIdType =
(EmbeddedComponentType) persister.getEntityMetamodel().getIdentifierProperty().getType();
if ( dependentIdType.getSubtypes().length == 1 ) {
final Type singleSubType = dependentIdType.getSubtypes()[0];
if ( singleSubType.isEntityType() ) {
final EntityType dependentParentType = (EntityType) singleSubType;
final Type dependentParentIdType = dependentParentType.getIdentifierOrUniqueKeyType( source.getFactory() );
if ( dependentParentIdType.getReturnedClass().isInstance( event.getEntityId() ) ) {
// yep that's what we have...
loadByDerivedIdentitySimplePkValue(
event,
loadType,
persister,
dependentIdType,
source.getFactory().getEntityPersister( dependentParentType.getAssociatedEntityName() )
);
return;
}
}
}
}
throw new TypeMismatchException(
"Provided id of the wrong type for class " + persister.getEntityName() + ". Expected: " + idClass + ", got " + event.getEntityId().getClass()
);
}
}
EntityKey keyToLoad = new EntityKey( event.getEntityId(), persister, source.getEntityMode() );
try {
if ( loadType.isNakedEntityReturned() ) {
//do not return a proxy!
//(this option indicates we are initializing a proxy)
event.setResult( load(event, persister, keyToLoad, loadType) );
}
else {
//return a proxy if appropriate
if ( event.getLockMode() == LockMode.NONE ) {
event.setResult( proxyOrLoad(event, persister, keyToLoad, loadType) );
}
else {
event.setResult( lockAndLoad(event, persister, keyToLoad, loadType, source) );
}
}
}
catch(HibernateException e) {
log.info("Error performing load command", e);
throw e;
}
}
private void loadByDerivedIdentitySimplePkValue(
LoadEvent event,
LoadEventListener.LoadType options,
EntityPersister dependentPersister,
EmbeddedComponentType dependentIdType,
EntityPersister parentPersister) {
final EntityKey parentEntityKey = new EntityKey(
event.getEntityId(),
parentPersister,
event.getSession().getEntityMode()
);
final Object parent = doLoad(
event,
parentPersister,
parentEntityKey,
options
);
Serializable dependent = (Serializable) dependentIdType.instantiate( parent, event.getSession() );
dependentIdType.setPropertyValues( dependent, new Object[] {parent}, event.getSession().getEntityMode() );
final EntityKey dependentEntityKey = new EntityKey(
dependent,
dependentPersister,
event.getSession().getEntityMode()
);
event.setEntityId( dependent );
dependent = (Serializable) doLoad(
event,
dependentPersister,
dependentEntityKey,
options
);
event.setResult( dependent );
}
/**
* Perfoms the load of an entity.
*
* @param event The initiating load request event
* @param persister The persister corresponding to the entity to be loaded
* @param keyToLoad The key of the entity to be loaded
* @param options The defined load options
* @return The loaded entity.
* @throws HibernateException
*/
protected Object load(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options) {
if ( event.getInstanceToLoad() != null ) {
if ( event.getSession().getPersistenceContext().getEntry( event.getInstanceToLoad() ) != null ) {
throw new PersistentObjectException(
"attempted to load into an instance that was already associated with the session: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
persister.setIdentifier( event.getInstanceToLoad(), event.getEntityId(), event.getSession() );
}
Object entity = doLoad(event, persister, keyToLoad, options);
boolean isOptionalInstance = event.getInstanceToLoad() != null;
if ( !options.isAllowNulls() || isOptionalInstance ) {
if ( entity == null ) {
event.getSession().getFactory().getEntityNotFoundDelegate().handleEntityNotFound( event.getEntityClassName(), event.getEntityId() );
}
}
if ( isOptionalInstance && entity != event.getInstanceToLoad() ) {
throw new NonUniqueObjectException( event.getEntityId(), event.getEntityClassName() );
}
return entity;
}
/**
* Based on configured options, will either return a pre-existing proxy,
* generate a new proxy, or perform an actual load.
*
* @param event The initiating load request event
* @param persister The persister corresponding to the entity to be loaded
* @param keyToLoad The key of the entity to be loaded
* @param options The defined load options
* @return The result of the proxy/load operation.
*/
protected Object proxyOrLoad(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options) {
if ( log.isTraceEnabled() ) {
log.trace(
"loading entity: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
if ( !persister.hasProxy() ) {
// this class has no proxies (so do a shortcut)
return load(event, persister, keyToLoad, options);
}
else {
final PersistenceContext persistenceContext = event.getSession().getPersistenceContext();
// look for a proxy
Object proxy = persistenceContext.getProxy(keyToLoad);
if ( proxy != null ) {
return returnNarrowedProxy( event, persister, keyToLoad, options, persistenceContext, proxy );
}
else {
if ( options.isAllowProxyCreation() ) {
return createProxyIfNecessary( event, persister, keyToLoad, options, persistenceContext );
}
else {
// return a newly loaded object
return load(event, persister, keyToLoad, options);
}
}
}
}
/**
* Given a proxy, initialize it and/or narrow it provided either
* is necessary.
*
* @param event The initiating load request event
* @param persister The persister corresponding to the entity to be loaded
* @param keyToLoad The key of the entity to be loaded
* @param options The defined load options
* @param persistenceContext The originating session
* @param proxy The proxy to narrow
* @return The created/existing proxy
*/
private Object returnNarrowedProxy(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options,
final PersistenceContext persistenceContext,
final Object proxy) {
log.trace("entity proxy found in session cache");
LazyInitializer li = ( (HibernateProxy) proxy ).getHibernateLazyInitializer();
if ( li.isUnwrap() ) {
return li.getImplementation();
}
Object impl = null;
if ( !options.isAllowProxyCreation() ) {
impl = load( event, persister, keyToLoad, options );
if ( impl == null ) {
event.getSession().getFactory().getEntityNotFoundDelegate().handleEntityNotFound( persister.getEntityName(), keyToLoad.getIdentifier());
}
}
return persistenceContext.narrowProxy( proxy, persister, keyToLoad, impl );
}
/**
* If there is already a corresponding proxy associated with the
* persistence context, return it; otherwise create a proxy, associate it
* with the persistence context, and return the just-created proxy.
*
* @param event The initiating load request event
* @param persister The persister corresponding to the entity to be loaded
* @param keyToLoad The key of the entity to be loaded
* @param options The defined load options
* @param persistenceContext The originating session
* @return The created/existing proxy
*/
private Object createProxyIfNecessary(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options,
final PersistenceContext persistenceContext) {
Object existing = persistenceContext.getEntity( keyToLoad );
if ( existing != null ) {
// return existing object or initialized proxy (unless deleted)
log.trace( "entity found in session cache" );
if ( options.isCheckDeleted() ) {
EntityEntry entry = persistenceContext.getEntry( existing );
Status status = entry.getStatus();
if ( status == Status.DELETED || status == Status.GONE ) {
return null;
}
}
return existing;
}
else {
log.trace( "creating new proxy for entity" );
// return new uninitialized proxy
Object proxy = persister.createProxy( event.getEntityId(), event.getSession() );
persistenceContext.getBatchFetchQueue().addBatchLoadableEntityKey(keyToLoad);
persistenceContext.addProxy(keyToLoad, proxy);
return proxy;
}
}
/**
* If the class to be loaded has been configured with a cache, then lock
* given id in that cache and then perform the load.
*
* @param event The initiating load request event
* @param persister The persister corresponding to the entity to be loaded
* @param keyToLoad The key of the entity to be loaded
* @param options The defined load options
* @param source The originating session
* @return The loaded entity
* @throws HibernateException
*/
protected Object lockAndLoad(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options,
final SessionImplementor source) {
SoftLock lock = null;
final CacheKey ck;
if ( persister.hasCache() ) {
ck = new CacheKey(
event.getEntityId(),
persister.getIdentifierType(),
persister.getRootEntityName(),
source.getEntityMode(),
source.getFactory()
);
lock = persister.getCacheAccessStrategy().lockItem( ck, null );
}
else {
ck = null;
}
Object entity;
try {
entity = load(event, persister, keyToLoad, options);
}
finally {
if ( persister.hasCache() ) {
persister.getCacheAccessStrategy().unlockItem( ck, lock );
}
}
return event.getSession().getPersistenceContext().proxyFor( persister, keyToLoad, entity );
}
/**
* Coordinates the efforts to load a given entity. First, an attempt is
* made to load the entity from the session-level cache. If not found there,
* an attempt is made to locate it in second-level cache. Lastly, an
* attempt is made to load it directly from the datasource.
*
* @param event The load event
* @param persister The persister for the entity being requested for load
* @param keyToLoad The EntityKey representing the entity to be loaded.
* @param options The load options.
* @return The loaded entity, or null.
*/
protected Object doLoad(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options) {
if ( log.isTraceEnabled() ) {
log.trace(
"attempting to resolve: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
Object entity = loadFromSessionCache( event, keyToLoad, options );
if ( entity == REMOVED_ENTITY_MARKER ) {
log.debug( "load request found matching entity in context, but it is scheduled for removal; returning null" );
return null;
}
if ( entity == INCONSISTENT_RTN_CLASS_MARKER ) {
log.debug( "load request found matching entity in context, but the matched entity was of an inconsistent return type; returning null" );
return null;
}
if ( entity != null ) {
if ( log.isTraceEnabled() ) {
log.trace(
"resolved object in session cache: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
return entity;
}
entity = loadFromSecondLevelCache(event, persister, options);
if ( entity != null ) {
if ( log.isTraceEnabled() ) {
log.trace(
"resolved object in second-level cache: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
return entity;
}
if ( log.isTraceEnabled() ) {
log.trace(
"object not resolved in any cache: " +
MessageHelper.infoString( persister, event.getEntityId(), event.getSession().getFactory() )
);
}
return loadFromDatasource(event, persister, keyToLoad, options);
}
/**
* Performs the process of loading an entity from the configured
* underlying datasource.
*
* @param event The load event
* @param persister The persister for the entity being requested for load
* @param keyToLoad The EntityKey representing the entity to be loaded.
* @param options The load options.
* @return The object loaded from the datasource, or null if not found.
*/
protected Object loadFromDatasource(
final LoadEvent event,
final EntityPersister persister,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options) {
final SessionImplementor source = event.getSession();
Object entity = persister.load(
event.getEntityId(),
event.getInstanceToLoad(),
event.getLockOptions(),
source
);
if ( event.isAssociationFetch() && source.getFactory().getStatistics().isStatisticsEnabled() ) {
source.getFactory().getStatisticsImplementor().fetchEntity( event.getEntityClassName() );
}
return entity;
}
/**
* Attempts to locate the entity in the session-level cache.
*
* If allowed to return nulls, then if the entity happens to be found in
* the session cache, we check the entity type for proper handling
* of entity hierarchies.
*
* If checkDeleted was set to true, then if the entity is found in the
* session-level cache, it's current status within the session cache
* is checked to see if it has previously been scheduled for deletion.
*
* @param event The load event
* @param keyToLoad The EntityKey representing the entity to be loaded.
* @param options The load options.
* @return The entity from the session-level cache, or null.
* @throws HibernateException Generally indicates problems applying a lock-mode.
*/
protected Object loadFromSessionCache(
final LoadEvent event,
final EntityKey keyToLoad,
final LoadEventListener.LoadType options) throws HibernateException {
SessionImplementor session = event.getSession();
Object old = session.getEntityUsingInterceptor( keyToLoad );
if ( old != null ) {
// this object was already loaded
EntityEntry oldEntry = session.getPersistenceContext().getEntry( old );
if ( options.isCheckDeleted() ) {
Status status = oldEntry.getStatus();
if ( status == Status.DELETED || status == Status.GONE ) {
return REMOVED_ENTITY_MARKER;
}
}
if ( options.isAllowNulls() ) {
EntityPersister persister = event.getSession().getFactory().getEntityPersister( event.getEntityClassName() );
if ( ! persister.isInstance( old, event.getSession().getEntityMode() ) ) {
return INCONSISTENT_RTN_CLASS_MARKER;
}
}
upgradeLock( old, oldEntry, event.getLockOptions(), event.getSession() );
}
return old;
}
/**
* Attempts to load the entity from the second-level cache.
*
* @param event The load event
* @param persister The persister for the entity being requested for load
* @param options The load options.
* @return The entity from the second-level cache, or null.
*/
protected Object loadFromSecondLevelCache(
final LoadEvent event,
final EntityPersister persister,
final LoadEventListener.LoadType options) {
final SessionImplementor source = event.getSession();
final boolean useCache = persister.hasCache()
&& source.getCacheMode().isGetEnabled()
&& event.getLockMode().lessThan(LockMode.READ);
if ( useCache ) {
final SessionFactoryImplementor factory = source.getFactory();
final CacheKey ck = new CacheKey(
event.getEntityId(),
persister.getIdentifierType(),
persister.getRootEntityName(),
source.getEntityMode(),
source.getFactory()
);
Object ce = persister.getCacheAccessStrategy().get( ck, source.getTimestamp() );
if ( factory.getStatistics().isStatisticsEnabled() ) {
if ( ce == null ) {
factory.getStatisticsImplementor().secondLevelCacheMiss(
persister.getCacheAccessStrategy().getRegion().getName()
);
}
else {
factory.getStatisticsImplementor().secondLevelCacheHit(
persister.getCacheAccessStrategy().getRegion().getName()
);
}
}
if ( ce != null ) {
CacheEntry entry = (CacheEntry) persister.getCacheEntryStructure().destructure( ce, factory );
// Entity was found in second-level cache...
return assembleCacheEntry(
entry,
event.getEntityId(),
persister,
event
);
}
}
return null;
}
private Object assembleCacheEntry(
final CacheEntry entry,
final Serializable id,
final EntityPersister persister,
final LoadEvent event) throws HibernateException {
final Object optionalObject = event.getInstanceToLoad();
final EventSource session = event.getSession();
final SessionFactoryImplementor factory = session.getFactory();
if ( log.isTraceEnabled() ) {
log.trace(
"assembling entity from second-level cache: " +
MessageHelper.infoString( persister, id, factory )
);
}
EntityPersister subclassPersister = factory.getEntityPersister( entry.getSubclass() );
Object result = optionalObject == null ?
session.instantiate( subclassPersister, id ) : optionalObject;
// make it circular-reference safe
EntityKey entityKey = new EntityKey( id, subclassPersister, session.getEntityMode() );
TwoPhaseLoad.addUninitializedCachedEntity(
entityKey,
result,
subclassPersister,
LockMode.NONE,
entry.areLazyPropertiesUnfetched(),
entry.getVersion(),
session
);
Type[] types = subclassPersister.getPropertyTypes();
Object[] values = entry.assemble( result, id, subclassPersister, session.getInterceptor(), session ); // intializes result by side-effect
TypeFactory.deepCopy(
values,
types,
subclassPersister.getPropertyUpdateability(),
values,
session
);
Object version = Versioning.getVersion( values, subclassPersister );
if ( log.isTraceEnabled() ) log.trace( "Cached Version: " + version );
final PersistenceContext persistenceContext = session.getPersistenceContext();
boolean isReadOnly = session.isDefaultReadOnly();
if ( persister.isMutable() ) {
Object proxy = persistenceContext.getProxy( entityKey );
if ( proxy != null ) {
// there is already a proxy for this impl
// only set the status to read-only if the proxy is read-only
isReadOnly = ( ( HibernateProxy ) proxy ).getHibernateLazyInitializer().isReadOnly();
}
}
else {
isReadOnly = true;
}
persistenceContext.addEntry(
result,
( isReadOnly ? Status.READ_ONLY : Status.MANAGED ),
values,
null,
id,
version,
LockMode.NONE,
true,
subclassPersister,
false,
entry.areLazyPropertiesUnfetched()
);
subclassPersister.afterInitialize( result, entry.areLazyPropertiesUnfetched(), session );
persistenceContext.initializeNonLazyCollections();
// upgrade the lock if necessary:
//lock(result, lockMode);
//PostLoad is needed for EJB3
//TODO: reuse the PostLoadEvent...
PostLoadEvent postLoadEvent = new PostLoadEvent(session).setEntity(result)
.setId(id).setPersister(persister);
PostLoadEventListener[] listeners = session.getListeners().getPostLoadEventListeners();
for ( int i = 0; i < listeners.length; i++ ) {
listeners[i].onPostLoad(postLoadEvent);
}
return result;
}
}
