AndPredicateCreator.java

package fi.codecrew.moya.facade.callbacks;

import java.util.Collections;
import java.util.List;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.From;
import javax.persistence.criteria.Predicate;
import javax.persistence.metamodel.SingularAttribute;

import fi.insomnia.bortal.utilities.jpa.ModelInterface;

public class AndPredicateCreator<A, T extends ModelInterface> implements FacadeCallback<T> {
	private final A searchval;
	private final List<SingularAttribute<T, A>> attributes;

	public AndPredicateCreator(A search, List<SingularAttribute<T, A>> attrs) {
		searchval = search;
		attributes = attrs;
	}

	public AndPredicateCreator(A search, SingularAttribute<T, A> attr) {
		searchval = search;
		attributes = Collections.singletonList(attr);
	}

	@Override
	public void exec(CriteriaBuilder cb, CriteriaQuery<?> cq, From<?, T> root, List<Predicate> predicates) {
		if (searchval == null || attributes == null || attributes.isEmpty()) {
			return;
		}
		if (attributes.size() > 1) {
			Predicate[] preds = new Predicate[attributes.size()];
			int i = 0;
			for (SingularAttribute<T, A> attr : attributes) {
				preds[i++] = cb.equal(root.get(attr), searchval);
			}
			predicates.add(cb.and(preds));
		} else {
			predicates.add(cb.equal(root.get(attributes.get(0)), searchval));
		}
	}
}