Hibernate example source code file (HolderInstantiator.java)

This example Hibernate source code file (HolderInstantiator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

aliastobeanconstructorresulttransformer, aliastobeanconstructorresulttransformer, constructor, holderinstantiator, holderinstantiator, noop_instantiator, object, reflection, resulttransformer, resulttransformer, string, string

The Hibernate HolderInstantiator.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
 *
 * 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.hql.internal;
import java.lang.reflect.Constructor;
import org.hibernate.transform.AliasToBeanConstructorResultTransformer;
import org.hibernate.transform.ResultTransformer;
import org.hibernate.transform.Transformers;

/**
 * @author Gavin King
 */
public final class HolderInstantiator {
		
	public static final HolderInstantiator NOOP_INSTANTIATOR = new HolderInstantiator(null,null);
	
	private final ResultTransformer transformer;
	private final String[] queryReturnAliases;
	
	public static HolderInstantiator getHolderInstantiator(ResultTransformer selectNewTransformer, ResultTransformer customTransformer, String[] queryReturnAliases) {
		return new HolderInstantiator(
				resolveResultTransformer( selectNewTransformer, customTransformer ),
				queryReturnAliases
		);
	}

	public static ResultTransformer resolveResultTransformer(ResultTransformer selectNewTransformer, ResultTransformer customTransformer) {
		return selectNewTransformer != null ? selectNewTransformer : customTransformer;
	}	

	public static ResultTransformer createSelectNewTransformer(Constructor constructor, boolean returnMaps, boolean returnLists) {
		if ( constructor != null ) {
			return new AliasToBeanConstructorResultTransformer(constructor);
		}
		else if ( returnMaps ) {
			return Transformers.ALIAS_TO_ENTITY_MAP;			
		}
		else if ( returnLists ) {
			return Transformers.TO_LIST;
		}		
		else {
			return null;
		}
	}
	
	static public HolderInstantiator createClassicHolderInstantiator(Constructor constructor, 
			ResultTransformer transformer) {
		return new HolderInstantiator( resolveClassicResultTransformer( constructor, transformer ), null );
	}

	static public ResultTransformer resolveClassicResultTransformer(
			Constructor constructor,
			ResultTransformer transformer) {
		return constructor != null ? new AliasToBeanConstructorResultTransformer( constructor ) : transformer;
	}	

	public HolderInstantiator( 
			ResultTransformer transformer,
			String[] queryReturnAliases
	) {
		this.transformer = transformer;		
		this.queryReturnAliases = queryReturnAliases;
	}
	
	public boolean isRequired() {
		return transformer!=null;
	}
	
	public Object instantiate(Object[] row) {
		if(transformer==null) {
			return row;
		} else {
			return transformer.transformTuple(row, queryReturnAliases);
		}
	}	
	
	public String[] getQueryReturnAliases() {
		return queryReturnAliases;
	}

	public ResultTransformer getResultTransformer() {
		return transformer;
	}

}