/*
* 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.transform;
import java.util.Arrays;
import org.hibernate.HibernateException;
import org.hibernate.property.ChainedPropertyAccessor;
import org.hibernate.property.PropertyAccessor;
import org.hibernate.property.PropertyAccessorFactory;
import org.hibernate.property.Setter;
/**
* Result transformer that allows to transform a result to
* a user specified class which will be populated via setter
* methods or fields matching the alias names.
* <p/>
* <pre>
* List resultWithAliasedBean = s.createCriteria(Enrolment.class)
* .createAlias("student", "st")
* .createAlias("course", "co")
* .setProjection( Projections.projectionList()
* .add( Projections.property("co.description"), "courseDescription" )
* )
* .setResultTransformer( new AliasToBeanResultTransformer(StudentDTO.class) )
* .list();
* <p/>
* StudentDTO dto = (StudentDTO)resultWithAliasedBean.get(0);
* </pre>
*
* @author max
*/
public class AliasToBeanResultTransformer extends AliasedTupleSubsetResultTransformer {
// IMPL NOTE : due to the delayed population of setters (setters cached
// for performance), we really cannot pro0perly define equality for
// this transformer
private final Class resultClass;
private boolean isInitialized;
private String[] aliases;
private Setter[] setters;
public AliasToBeanResultTransformer(Class resultClass) {
if ( resultClass == null ) {
throw new IllegalArgumentException( "resultClass cannot be null" );
}
this.isInitialized = false;
this.resultClass = resultClass;
}
/**
* {@inheritDoc}
*/
public boolean isTransformedValueATupleElement(String[] aliases, int tupleLength) {
return false;
}
public Object transformTuple(Object[] tuple, String[] aliases) {
Object result;
try {
if ( ! isInitialized ) {
initialize( aliases );
}
else {
check( aliases );
}
result = resultClass.newInstance();
for ( int i = 0; i < aliases.length; i++ ) {
if ( setters[i] != null ) {
setters[i].set( result, tuple[i], null );
}
}
}
catch ( InstantiationException e ) {
throw new HibernateException( "Could not instantiate resultclass: " + resultClass.getName() );
}
catch ( IllegalAccessException e ) {
throw new HibernateException( "Could not instantiate resultclass: " + resultClass.getName() );
}
return result;
}
private void initialize(String[] aliases) {
PropertyAccessor propertyAccessor = new ChainedPropertyAccessor(
new PropertyAccessor[] {
PropertyAccessorFactory.getPropertyAccessor( resultClass, null ),
PropertyAccessorFactory.getPropertyAccessor( "field" )
}
);
this.aliases = new String[ aliases.length ];
setters = new Setter[ aliases.length ];
for ( int i = 0; i < aliases.length; i++ ) {
String alias = aliases[ i ];
if ( alias != null ) {
this.aliases[ i ] = alias;
setters[ i ] = propertyAccessor.getSetter( resultClass, alias );
}
}
isInitialized = true;
}
private void check(String[] aliases) {
if ( ! Arrays.equals( aliases, this.aliases ) ) {
throw new IllegalStateException(
"aliases are different from what is cached; aliases=" + Arrays.asList( aliases ) +
" cached=" + Arrays.asList( this.aliases ) );
}
}
public boolean equals(Object o) {
if ( this == o ) {
return true;
}
if ( o == null || getClass() != o.getClass() ) {
return false;
}
AliasToBeanResultTransformer that = ( AliasToBeanResultTransformer ) o;
if ( ! resultClass.equals( that.resultClass ) ) {
return false;
}
if ( ! Arrays.equals( aliases, that.aliases ) ) {
return false;
}
return true;
}
public int hashCode() {
int result = resultClass.hashCode();
result = 31 * result + ( aliases != null ? Arrays.hashCode( aliases ) : 0 );
return result;
}
}