/*
* 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
* 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.engine.loading.internal;
import java.io.Serializable;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.jboss.logging.Logger;
import org.hibernate.CacheMode;
import org.hibernate.EntityMode;
import org.hibernate.HibernateException;
import org.hibernate.cache.spi.CacheKey;
import org.hibernate.collection.spi.PersistentCollection;
import org.hibernate.engine.spi.CollectionKey;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.cache.spi.entry.CollectionCacheEntry;
import org.hibernate.engine.spi.CollectionEntry;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.spi.Status;
import org.hibernate.persister.collection.CollectionPersister;
import org.hibernate.pretty.MessageHelper;
/**
* Represents state associated with the processing of a given {@link ResultSet}
* in regards to loading collections.
* <p/>
* Another implementation option to consider is to not expose {@link ResultSet}s
* directly (in the JDBC redesign) but to always "wrap" them and apply a
* [series of] context[s] to that wrapper.
*
* @author Steve Ebersole
*/
public class CollectionLoadContext {
private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, CollectionLoadContext.class.getName());
private final LoadContexts loadContexts;
private final ResultSet resultSet;
private Set localLoadingCollectionKeys = new HashSet();
/**
* Creates a collection load context for the given result set.
*
* @param loadContexts Callback to other collection load contexts.
* @param resultSet The result set this is "wrapping".
*/
public CollectionLoadContext(LoadContexts loadContexts, ResultSet resultSet) {
this.loadContexts = loadContexts;
this.resultSet = resultSet;
}
public ResultSet getResultSet() {
return resultSet;
}
public LoadContexts getLoadContext() {
return loadContexts;
}
/**
* Retrieve the collection that is being loaded as part of processing this
* result set.
* <p/>
* Basically, there are two valid return values from this method:<ul>
* <li>an instance of {@link org.hibernate.collection.spi.PersistentCollection} which indicates to
* continue loading the result set row data into that returned collection
* instance; this may be either an instance already associated and in the
* midst of being loaded, or a newly instantiated instance as a matching
* associated collection was not found.</li>
* <li><i>null</i> indicates to ignore the corresponding result set row
* data relating to the requested collection; this indicates that either
* the collection was found to already be associated with the persistence
* context in a fully loaded state, or it was found in a loading state
* associated with another result set processing context.</li>
* </ul>
*
* @param persister The persister for the collection being requested.
* @param key The key of the collection being requested.
*
* @return The loading collection (see discussion above).
*/
public PersistentCollection getLoadingCollection(final CollectionPersister persister, final Serializable key) {
final EntityMode em = persister.getOwnerEntityPersister().getEntityMetamodel().getEntityMode();
final CollectionKey collectionKey = new CollectionKey( persister, key, em );
if (LOG.isTraceEnabled()) LOG.trace("Starting attempt to find loading collection ["
+ MessageHelper.collectionInfoString(persister.getRole(), key) + "]");
final LoadingCollectionEntry loadingCollectionEntry = loadContexts.locateLoadingCollectionEntry( collectionKey );
if ( loadingCollectionEntry == null ) {
// look for existing collection as part of the persistence context
PersistentCollection collection = loadContexts.getPersistenceContext().getCollection( collectionKey );
if ( collection != null ) {
if ( collection.wasInitialized() ) {
LOG.trace("Collection already initialized; ignoring");
return null; // ignore this row of results! Note the early exit
}
LOG.trace("Collection not yet initialized; initializing");
}
else {
Object owner = loadContexts.getPersistenceContext().getCollectionOwner( key, persister );
final boolean newlySavedEntity = owner != null
&& loadContexts.getPersistenceContext().getEntry( owner ).getStatus() != Status.LOADING;
if ( newlySavedEntity ) {
// important, to account for newly saved entities in query
// todo : some kind of check for new status...
LOG.trace("Owning entity already loaded; ignoring");
return null;
}
// create one
LOG.trace("Instantiating new collection [key=" + key + ", rs=" + resultSet + "]");
collection = persister.getCollectionType().instantiate(loadContexts.getPersistenceContext().getSession(),
persister,
key);
}
collection.beforeInitialize( persister, -1 );
collection.beginRead();
localLoadingCollectionKeys.add( collectionKey );
loadContexts.registerLoadingCollectionXRef( collectionKey, new LoadingCollectionEntry( resultSet, persister, key, collection ) );
return collection;
}
if (loadingCollectionEntry.getResultSet() == resultSet) {
LOG.trace("Found loading collection bound to current result set processing; reading row");
return loadingCollectionEntry.getCollection();
}
// ignore this row, the collection is in process of
// being loaded somewhere further "up" the stack
LOG.trace("Collection is already being initialized; ignoring row");
return null;
}
/**
* Finish the process of collection-loading for this bound result set. Mainly this
* involves cleaning up resources and notifying the collections that loading is
* complete.
*
* @param persister The persister for which to complete loading.
*/
public void endLoadingCollections(CollectionPersister persister) {
SessionImplementor session = getLoadContext().getPersistenceContext().getSession();
if ( !loadContexts.hasLoadingCollectionEntries()
&& localLoadingCollectionKeys.isEmpty() ) {
return;
}
// in an effort to avoid concurrent-modification-exceptions (from
// potential recursive calls back through here as a result of the
// eventual call to PersistentCollection#endRead), we scan the
// internal loadingCollections map for matches and store those matches
// in a temp collection. the temp collection is then used to "drive"
// the #endRead processing.
List matches = null;
Iterator iter = localLoadingCollectionKeys.iterator();
while ( iter.hasNext() ) {
final CollectionKey collectionKey = (CollectionKey) iter.next();
final LoadingCollectionEntry lce = loadContexts.locateLoadingCollectionEntry( collectionKey );
if (lce == null) LOG.loadingCollectionKeyNotFound(collectionKey);
else if ( lce.getResultSet() == resultSet && lce.getPersister() == persister ) {
if ( matches == null ) {
matches = new ArrayList();
}
matches.add( lce );
if ( lce.getCollection().getOwner() == null ) {
session.getPersistenceContext().addUnownedCollection(
new CollectionKey(
persister,
lce.getKey(),
persister.getOwnerEntityPersister().getEntityMetamodel().getEntityMode()
),
lce.getCollection()
);
}
LOG.trace("Removing collection load entry [" + lce + "]");
// todo : i'd much rather have this done from #endLoadingCollection(CollectionPersister,LoadingCollectionEntry)...
loadContexts.unregisterLoadingCollectionXRef( collectionKey );
iter.remove();
}
}
endLoadingCollections( persister, matches );
if ( localLoadingCollectionKeys.isEmpty() ) {
// todo : hack!!!
// NOTE : here we cleanup the load context when we have no more local
// LCE entries. This "works" for the time being because really
// only the collection load contexts are implemented. Long term,
// this cleanup should become part of the "close result set"
// processing from the (sandbox/jdbc) jdbc-container code.
loadContexts.cleanup( resultSet );
}
}
private void endLoadingCollections(CollectionPersister persister, List matchedCollectionEntries) {
if ( matchedCollectionEntries == null ) {
LOG.debugf("No collections were found in result set for role: %s", persister.getRole());
return;
}
final int count = matchedCollectionEntries.size();
LOG.debugf("%s collections were found in result set for role: %s", count, persister.getRole());
for ( int i = 0; i < count; i++ ) {
LoadingCollectionEntry lce = ( LoadingCollectionEntry ) matchedCollectionEntries.get( i );
endLoadingCollection( lce, persister );
}
LOG.debugf("%s collections initialized for role: %s", count, persister.getRole());
}
private void endLoadingCollection(LoadingCollectionEntry lce, CollectionPersister persister) {
LOG.trace("Ending loading collection [" + lce + "]");
final SessionImplementor session = getLoadContext().getPersistenceContext().getSession();
boolean hasNoQueuedAdds = lce.getCollection().endRead(); // warning: can cause a recursive calls! (proxy initialization)
if ( persister.getCollectionType().hasHolder() ) {
getLoadContext().getPersistenceContext().addCollectionHolder( lce.getCollection() );
}
CollectionEntry ce = getLoadContext().getPersistenceContext().getCollectionEntry( lce.getCollection() );
if ( ce == null ) {
ce = getLoadContext().getPersistenceContext().addInitializedCollection( persister, lce.getCollection(), lce.getKey() );
}
else {
ce.postInitialize( lce.getCollection() );
}
boolean addToCache = hasNoQueuedAdds && // there were no queued additions
persister.hasCache() && // and the role has a cache
session.getCacheMode().isPutEnabled() &&
!ce.isDoremove(); // and this is not a forced initialization during flush
if (addToCache) addCollectionToCache(lce, persister);
if (LOG.isDebugEnabled()) {
LOG.debugf(
"Collection fully initialized: %s",
MessageHelper.collectionInfoString(persister, lce.getKey(), session.getFactory())
);
}
if (session.getFactory().getStatistics().isStatisticsEnabled()) {
session.getFactory().getStatisticsImplementor().loadCollection(persister.getRole());
}
}
/**
* Add the collection to the second-level cache
*
* @param lce The entry representing the collection to add
* @param persister The persister
*/
private void addCollectionToCache(LoadingCollectionEntry lce, CollectionPersister persister) {
final SessionImplementor session = getLoadContext().getPersistenceContext().getSession();
final SessionFactoryImplementor factory = session.getFactory();
if (LOG.isDebugEnabled()) LOG.debugf("Caching collection: %s",
MessageHelper.collectionInfoString(persister, lce.getKey(), factory));
if ( !session.getEnabledFilters().isEmpty() && persister.isAffectedByEnabledFilters( session ) ) {
// some filters affecting the collection are enabled on the session, so do not do the put into the cache.
LOG.debugf("Refusing to add to cache due to enabled filters");
// todo : add the notion of enabled filters to the CacheKey to differentiate filtered collections from non-filtered;
// but CacheKey is currently used for both collections and entities; would ideally need to define two seperate ones;
// currently this works in conjuction with the check on
// DefaultInitializeCollectionEventHandler.initializeCollectionFromCache() (which makes sure to not read from
// cache with enabled filters).
return; // EARLY EXIT!!!!!
}
final Object version;
if ( persister.isVersioned() ) {
Object collectionOwner = getLoadContext().getPersistenceContext().getCollectionOwner( lce.getKey(), persister );
if ( collectionOwner == null ) {
// generally speaking this would be caused by the collection key being defined by a property-ref, thus
// the collection key and the owner key would not match up. In this case, try to use the key of the
// owner instance associated with the collection itself, if one. If the collection does already know
// about its owner, that owner should be the same instance as associated with the PC, but we do the
// resolution against the PC anyway just to be safe since the lookup should not be costly.
if ( lce.getCollection() != null ) {
Object linkedOwner = lce.getCollection().getOwner();
if ( linkedOwner != null ) {
final Serializable ownerKey = persister.getOwnerEntityPersister().getIdentifier( linkedOwner, session );
collectionOwner = getLoadContext().getPersistenceContext().getCollectionOwner( ownerKey, persister );
}
}
if ( collectionOwner == null ) {
throw new HibernateException(
"Unable to resolve owner of loading collection [" +
MessageHelper.collectionInfoString( persister, lce.getKey(), factory ) +
"] for second level caching"
);
}
}
version = getLoadContext().getPersistenceContext().getEntry( collectionOwner ).getVersion();
}
else {
version = null;
}
CollectionCacheEntry entry = new CollectionCacheEntry( lce.getCollection(), persister );
CacheKey cacheKey = session.generateCacheKey( lce.getKey(), persister.getKeyType(), persister.getRole() );
boolean put = persister.getCacheAccessStrategy().putFromLoad(
cacheKey,
persister.getCacheEntryStructure().structure(entry),
session.getTimestamp(),
version,
factory.getSettings().isMinimalPutsEnabled() && session.getCacheMode()!= CacheMode.REFRESH
);
if ( put && factory.getStatistics().isStatisticsEnabled() ) {
factory.getStatisticsImplementor().secondLevelCachePut( persister.getCacheAccessStrategy().getRegion().getName() );
}
}
void cleanup() {
if (!localLoadingCollectionKeys.isEmpty()) LOG.localLoadingCollectionKeysCount(localLoadingCollectionKeys.size());
loadContexts.cleanupCollectionXRefs( localLoadingCollectionKeys );
localLoadingCollectionKeys.clear();
}
@Override
public String toString() {
return super.toString() + "<rs=" + resultSet + ">";
}
}