/*
* Created on 27-Jan-2005
*
*/
package org.hibernate.transform;
import java.util.List;
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.
*
* <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();
*
* StudentDTO dto = (StudentDTO)resultWithAliasedBean.get(0);
* </pre>
*
* @author max
*
*/
public class AliasToBeanResultTransformer implements ResultTransformer {
private final Class resultClass;
private Setter[] setters;
private PropertyAccessor propertyAccessor;
public AliasToBeanResultTransformer(Class resultClass) {
if(resultClass==null) throw new IllegalArgumentException("resultClass cannot be null");
this.resultClass = resultClass;
propertyAccessor = new ChainedPropertyAccessor(new PropertyAccessor[] { PropertyAccessorFactory.getPropertyAccessor(resultClass,null), PropertyAccessorFactory.getPropertyAccessor("field")});
}
public Object transformTuple(Object[] tuple, String[] aliases) {
Object result;
try {
if(setters==null) {
setters = new Setter[aliases.length];
for (int i = 0; i < aliases.length; i++) {
String alias = aliases[i];
if(alias != null) {
setters[i] = propertyAccessor.getSetter(resultClass, alias);
}
}
}
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;
}
public List transformList(List collection) {
return collection;
}
}