mapping Hibernate query results to custom class?

Question

Following up on a question I posted yesterday: How to populate POJO class from custom Hibernate query?

Can someone show me an example of how to code the following SQ

Answer 1

Below is a result transformer that ignores case:

package org.apec.abtc.dao.hibernate.transform;

import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.property.access.internal.PropertyAccessStrategyBasicImpl;
import org.hibernate.property.access.internal.PropertyAccessStrategyChainedImpl;
import org.hibernate.property.access.internal.PropertyAccessStrategyFieldImpl;
import org.hibernate.property.access.internal.PropertyAccessStrategyMapImpl;
import org.hibernate.property.access.spi.Setter;
import org.hibernate.transform.AliasedTupleSubsetResultTransformer;

/**
 * IgnoreCaseAlias to BeanResult Transformer
 * 
 * @author Stephen Gray
 */
public class IgnoreCaseAliasToBeanResultTransformer extends AliasedTupleSubsetResultTransformer
{

    /** The serialVersionUID field. */
    private static final long serialVersionUID = -3779317531110592988L;

    /** The resultClass field. */
    @SuppressWarnings("rawtypes")
    private final Class resultClass;
    /** The setters field. */
    private Setter[] setters;
    /** The fields field. */
    private Field[] fields;
    private String[] aliases;

    /**
     * @param resultClass
     */
    @SuppressWarnings("rawtypes")
    public IgnoreCaseAliasToBeanResultTransformer(final Class resultClass)
    {
        if (resultClass == null)
        {
            throw new IllegalArgumentException("resultClass cannot be null");
        }
        this.resultClass = resultClass;
        this.fields = this.resultClass.getDeclaredFields();
    }

    @Override
    public boolean isTransformedValueATupleElement(String[] aliases, int tupleLength) {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Object transformTuple(final Object[] tuple, final String[] aliases)
    {
        Object result;

        try
        {
            if (this.setters == null)
            {
                this.aliases = aliases;

                setSetters(aliases);
            }
            result = this.resultClass.newInstance();

            for (int i = 0; i < aliases.length; i++)
            {
                if (this.setters[i] != null)
                {
                    this.setters[i].set(result, tuple[i], null);
                }
            }
        }
        catch (final InstantiationException | IllegalAccessException e)
        {
            throw new HibernateException("Could not instantiate resultclass: " + this.resultClass.getName(), e);
        }

        return result;
    }

    private void setSetters(final String[] aliases)
    {
        PropertyAccessStrategyChainedImpl propertyAccessStrategy = new PropertyAccessStrategyChainedImpl(
                                                                                                         PropertyAccessStrategyBasicImpl.INSTANCE,
                                                                                                         PropertyAccessStrategyFieldImpl.INSTANCE,
                                                                                                         PropertyAccessStrategyMapImpl.INSTANCE
                                                                        );

        this.setters = new Setter[aliases.length];
        for (int i = 0; i < aliases.length; i++)
        {
            String alias = aliases[i];
            if (alias != null)
            {
                for (final Field field : this.fields)
                {
                    final String fieldName = field.getName();
                    if (fieldName.equalsIgnoreCase(alias))
                    {
                        alias = fieldName;
                        break;
                    }
                }
                setters[i] = propertyAccessStrategy.buildPropertyAccess( resultClass, alias ).getSetter();
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("rawtypes")
    public List transformList(final List collection)
    {
        return collection;
    }

    @Override
    public boolean equals(Object o) {
        if ( this == o ) {
            return true;
        }
        if ( o == null || getClass() != o.getClass() ) {
            return false;
        }

        IgnoreCaseAliasToBeanResultTransformer that = ( IgnoreCaseAliasToBeanResultTransformer ) o;

        if ( ! resultClass.equals( that.resultClass ) ) {
            return false;
        }
        if ( ! Arrays.equals( aliases, that.aliases ) ) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = resultClass.hashCode();
        result = 31 * result + ( aliases != null ? Arrays.hashCode( aliases ) : 0 );
        return result;
    }
}

Answer 2

In case you have a native query, all answers here use deprecated methods for newer versions of Hibernate, so if you are using 5.1+ this is the way to go:

// Note this is a org.hibernate.query.NativeQuery NOT Query.
NativeQuery query = getCurrentSession()
                .createNativeQuery(
                        "SELECT {y.*} , {x.*} from TableY y left join TableX x on x.id = y.id");


// This maps the results to entities. 
query.addEntity("x", TableXEntity.class);
query.addEntity("y", TableYEntity.class);

query.list()