/*
* 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.cache;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import javax.persistence.EntityNotFoundException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.HibernateException;
import org.hibernate.UnresolvableObjectException;
import org.hibernate.cfg.Settings;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.type.Type;
import org.hibernate.type.TypeHelper;
/**
* The standard implementation of the Hibernate QueryCache interface. This
* implementation is very good at recognizing stale query results and
* and re-running queries when it detects this condition, recaching the new
* results.
*
* @author Gavin King
* @author Steve Ebersole
*/
public class StandardQueryCache implements QueryCache {
private static final Logger log = LoggerFactory.getLogger( StandardQueryCache.class );
private QueryResultsRegion cacheRegion;
private UpdateTimestampsCache updateTimestampsCache;
public void clear() throws CacheException {
cacheRegion.evictAll();
}
public StandardQueryCache(
final Settings settings,
final Properties props,
final UpdateTimestampsCache updateTimestampsCache,
String regionName) throws HibernateException {
if ( regionName == null ) {
regionName = StandardQueryCache.class.getName();
}
String prefix = settings.getCacheRegionPrefix();
if ( prefix != null ) {
regionName = prefix + '.' + regionName;
}
log.info( "starting query cache at region: " + regionName );
this.cacheRegion = settings.getRegionFactory().buildQueryResultsRegion( regionName, props );
this.updateTimestampsCache = updateTimestampsCache;
}
@SuppressWarnings({ "UnnecessaryBoxing", "unchecked" })
public boolean put(
QueryKey key,
Type[] returnTypes,
List result,
boolean isNaturalKeyLookup,
SessionImplementor session) throws HibernateException {
if ( isNaturalKeyLookup && result.size() == 0 ) {
return false;
}
else {
Long ts = new Long( session.getFactory().getSettings().getRegionFactory().nextTimestamp());
if ( log.isDebugEnabled() ) {
log.debug( "caching query results in region: " + cacheRegion.getName() + "; timestamp=" + ts );
}
List cacheable = new ArrayList( result.size() + 1 );
cacheable.add( ts );
for ( Object aResult : result ) {
if ( returnTypes.length == 1 ) {
cacheable.add( returnTypes[0].disassemble( aResult, session, null ) );
}
else {
cacheable.add(
TypeHelper.disassemble( (Object[]) aResult, returnTypes, null, session, null )
);
}
}
cacheRegion.put( key, cacheable );
return true;
}
}
@SuppressWarnings({ "unchecked" })
public List get(
QueryKey key,
Type[] returnTypes,
boolean isNaturalKeyLookup,
Set spaces,
SessionImplementor session) throws HibernateException {
if ( log.isDebugEnabled() ) {
log.debug( "checking cached query results in region: " + cacheRegion.getName() );
}
List cacheable = ( List ) cacheRegion.get( key );
if ( cacheable == null ) {
log.debug( "query results were not found in cache" );
return null;
}
Long timestamp = ( Long ) cacheable.get( 0 );
if ( !isNaturalKeyLookup && !isUpToDate( spaces, timestamp ) ) {
log.debug( "cached query results were not up to date" );
return null;
}
log.debug( "returning cached query results" );
for ( int i = 1; i < cacheable.size(); i++ ) {
if ( returnTypes.length == 1 ) {
returnTypes[0].beforeAssemble( ( Serializable ) cacheable.get( i ), session );
}
else {
TypeHelper.beforeAssemble( ( Serializable[] ) cacheable.get( i ), returnTypes, session );
}
}
List result = new ArrayList( cacheable.size() - 1 );
for ( int i = 1; i < cacheable.size(); i++ ) {
try {
if ( returnTypes.length == 1 ) {
result.add( returnTypes[0].assemble( ( Serializable ) cacheable.get( i ), session, null ) );
}
else {
result.add(
TypeHelper.assemble( ( Serializable[] ) cacheable.get( i ), returnTypes, session, null )
);
}
}
catch ( RuntimeException ex ) {
if ( isNaturalKeyLookup &&
( UnresolvableObjectException.class.isInstance( ex ) ||
EntityNotFoundException.class.isInstance( ex ) ) ) {
//TODO: not really completely correct, since
// the uoe could occur while resolving
// associations, leaving the PC in an
// inconsistent state
log.debug( "could not reassemble cached result set" );
cacheRegion.evict( key );
return null;
}
else {
throw ex;
}
}
}
return result;
}
protected boolean isUpToDate(Set spaces, Long timestamp) {
if ( log.isDebugEnabled() ) {
log.debug( "Checking query spaces for up-to-dateness: " + spaces );
}
return updateTimestampsCache.isUpToDate( spaces, timestamp );
}
public void destroy() {
try {
cacheRegion.destroy();
}
catch ( Exception e ) {
log.warn( "could not destroy query cache: " + cacheRegion.getName(), e );
}
}
public QueryResultsRegion getRegion() {
return cacheRegion;
}
public String toString() {
return "StandardQueryCache(" + cacheRegion.getName() + ')';
}
}