//$Id: BatchingEntityLoader.java 6929 2005-05-27 03:54:08Z oneovthafew $ package org.hibernate.loader.entity; import java.io.Serializable; import java.util.Iterator; import java.util.List; import java.util.Map; import org.hibernate.HibernateException; import org.hibernate.LockMode; import org.hibernate.MappingException; import org.hibernate.engine.SessionFactoryImplementor; import org.hibernate.engine.SessionImplementor; import org.hibernate.loader.Loader; import org.hibernate.persister.entity.EntityPersister; import org.hibernate.persister.entity.OuterJoinLoadable; import org.hibernate.type.Type; import org.hibernate.util.ArrayHelper; /** * "Batch" loads entities, using multiple primary key values in the * SQL <tt>where</tt> clause. * * @see EntityLoader * @author Gavin King */ public class BatchingEntityLoader implements UniqueEntityLoader { private final Loader[] loaders; private final int[] batchSizes; private final EntityPersister persister; private final Type idType; public BatchingEntityLoader(EntityPersister persister, int[] batchSizes, Loader[] loaders) { this.batchSizes = batchSizes; this.loaders = loaders; this.persister = persister; idType = persister.getIdentifierType(); } private Object getObjectFromList(List results, Serializable id, SessionImplementor session) { // get the right object from the list ... would it be easier to just call getEntity() ?? Iterator iter = results.iterator(); while ( iter.hasNext() ) { Object obj = iter.next(); final boolean equal = idType.isEqual( id, session.getContextEntityIdentifier(obj), session.getEntityMode(), session.getFactory() ); if ( equal ) return obj; } return null; } public Object load(Serializable id, Object optionalObject, SessionImplementor session) throws HibernateException { Serializable[] batch = session.getPersistenceContext() .getBatchFetchQueue() .getEntityBatch( persister, id, batchSizes[0], session.getEntityMode() ); for ( int i=0; i<batchSizes.length-1; i++) { final int smallBatchSize = batchSizes[i]; if ( batch[smallBatchSize-1]!=null ) { Serializable[] smallBatch = new Serializable[smallBatchSize]; System.arraycopy(batch, 0, smallBatch, 0, smallBatchSize); final List results = loaders[i].loadEntityBatch( session, smallBatch, idType, optionalObject, persister.getEntityName(), id, persister ); return getObjectFromList(results, id, session); //EARLY EXIT } } return ( (UniqueEntityLoader) loaders[batchSizes.length-1] ).load(id, optionalObject, session); } public static UniqueEntityLoader createBatchingEntityLoader( final OuterJoinLoadable persister, final int maxBatchSize, final LockMode lockMode, final SessionFactoryImplementor factory, final Map enabledFilters) throws MappingException { if ( maxBatchSize>1 ) { int[] batchSizesToCreate = ArrayHelper.getBatchSizes(maxBatchSize); Loader[] loadersToCreate = new Loader[ batchSizesToCreate.length ]; for ( int i=0; i<batchSizesToCreate.length; i++ ) { loadersToCreate[i] = new EntityLoader(persister, batchSizesToCreate[i], lockMode, factory, enabledFilters); } return new BatchingEntityLoader(persister, batchSizesToCreate, loadersToCreate); } else { return new EntityLoader(persister, lockMode, factory, enabledFilters); } } }