public StandardQueryCache(Settings settings,
    Properties props,
    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;
}

 public  void clear() throws CacheException 
{
	     
		cacheRegion.evictAll();
}

 public  void destroy() 
{
		try {
			cacheRegion.destroy();
		}
		catch ( Exception e ) {
			log.warn( "could not destroy query cache: " + cacheRegion.getName(), e );
		}
}

 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 {
				TypeFactory.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(
							TypeFactory.assemble(
									( Serializable[] ) cacheable.get( i ), returnTypes, session, null
							)
					);
				}
			}
			catch ( UnresolvableObjectException uoe ) {
				if ( isNaturalKeyLookup ) {
					//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 uoe;
				}
			}
		}
		return result;
}

 public QueryResultsRegion getRegion() 
{
		return cacheRegion;
}

 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 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.getTimestamp() );
			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 ( int i = 0; i <  result.size(); i++ ) {
				if ( returnTypes.length == 1 ) {
					cacheable.add( returnTypes[0].disassemble( result.get( i ), session, null ) );
				}
				else {
					cacheable.add(
							TypeFactory.disassemble(
									( Object[] ) result.get( i ), returnTypes, null, session, null
							)
					);
				}
			}
			cacheRegion.put( key, cacheable );
			return true;
		}
}

 public String toString() 
{
		return "StandardQueryCache(" + cacheRegion.getName() + ')";
}