JpaDslTupleBuilder.java

package au.com.vaadinutils.dao;

import java.util.LinkedList;
import java.util.List;

import javax.persistence.Tuple;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Selection;
import javax.persistence.metamodel.SingularAttribute;

public class JpaDslTupleBuilder<E> extends JpaDslAbstract<E, Tuple>
{
	private List<Selection<?>> multiselects = new LinkedList<>();

	JpaDslTupleBuilder(Class<E> entityClass)
	{
		this.entityClass = entityClass;
		builder = getEntityManager().getCriteriaBuilder();

		criteria = builder.createTupleQuery();
		root = criteria.from(entityClass);
	}

	public <T> Path<T> multiselect(final SingularAttribute<E, T> attribute)
	{
		final Path<T> path = root.get(attribute);
		multiselects.add(path);

		return path;
	}

	public <T> Path<T> multiselect(final Path<T> path)
	{
		multiselects.add(path);

		return path;
	}

	public <J, T> Path<T> multiselect(final JoinBuilder<E, J> join, final SingularAttribute<J, T> attribute)
	{
		final Path<T> path = getJoin(join).get(attribute);
		multiselects.add(path);

		return path;
	}

	public <J, T> Selection<T> multiselect(final JoinBuilder<E, J> join, final SingularAttribute<J, T> attribute, final String alias)
	{
		final Selection<T> selection = getJoin(join).get(attribute).alias(alias);
		multiselects.add(selection);

		return selection;
	}
	
	public JpaDslTupleBuilder<E> multiselect(final Selection<?> selection)
	{
		multiselects.add(selection);
		return this;
	}

	@Override
	public List<Tuple> getResultList()
	{
		criteria.multiselect(multiselects);
		return super.getResultList();
	}
	
	@Override
	public Tuple getSingleResult()
	{
		criteria.multiselect(multiselects);
		return super.getSingleResult();
	}

	@Override
	public Tuple getSingleResultOrNull()
	{
		criteria.multiselect(multiselects);
		return super.getSingleResultOrNull();
	}
}