JpaDao.java

/**
 * This file is part of Faktotum.
 import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.TypedQuery;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

import de.romankreisel.faktotum.FaktotumObject;
import de.romankreisel.faktotum.datamodel.FaktotumEntity;
import de.romankreisel.faktotum.datamodel.FaktotumEntity_;
U Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public 
 *  License along with Faktotum.  
 *
 *  If not, see <http://www.gnu.org/licenses/>.
 */
package de.romankreisel.faktotum.dao;

import java.util.List;
import java.util.logging.Level;

import javax.ejb.EJB;
import javax.ejb.Stateless;
import javax.persistence.TypedQuery;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

import de.romankreisel.faktotum.FaktotumObject;
import de.romankreisel.faktotum.datamodel.FaktotumEntity;
import de.romankreisel.faktotum.datamodel.FaktotumEntity_;

@Stateless
public abstract class JpaDao<E extends FaktotumEntity> extends FaktotumObject implements Dao<E> {
	@EJB
	StorageService storageService;

	/**
	 * Create a query which returns a Long value
	 * 
	 * @param criteriaQuery
	 *            The query criteria
	 * @return A TypedQuery for the criteria
	 */
	public TypedQuery<Long> createLongQuery(CriteriaQuery<Long> criteriaQuery) {
		return this.getStorageService().getEntityManager().createQuery(criteriaQuery);
	}

	/**
	 * Create a typed query for the given criteria
	 * 
	 * @param criteriaQuery
	 *            the query criteria
	 * @return A TypedQuery for the criteria
	 */
	public TypedQuery<E> createQuery(CriteriaQuery<E> criteriaQuery) {
		return this.getStorageService().getEntityManager().createQuery(criteriaQuery);
	}

	@Override
	public E findById(Long id, Class<E> searchedClass) {
		CriteriaBuilder criteriaBuilder = this.getCriteriaBuilder();
		CriteriaQuery<E> criteriaQuery = criteriaBuilder.createQuery(searchedClass);

		Root<E> entityRoot = criteriaQuery.from(searchedClass);
		Predicate condition = criteriaBuilder.equal(entityRoot.get(FaktotumEntity_.id), id);
		criteriaQuery.where(condition);
		TypedQuery<E> typedQuery = this.createQuery(criteriaQuery);
		return typedQuery.getSingleResult();
	}

	@Override
	public List<E> getAll(Class<E> searchedClass) {
		CriteriaBuilder criteriaBuilder = this.getCriteriaBuilder();
		CriteriaQuery<E> criteriaQuery = criteriaBuilder.createQuery(searchedClass);

		TypedQuery<E> typedQuery = this.createQuery(criteriaQuery);
		return typedQuery.getResultList();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see de.romankreisel.faktotum.dao.Dao#getCount(java.lang.Class)
	 */
	@Override
	public Long getCount(Class<E> searchedClass) {
		CriteriaBuilder criteriaBuilder = this.getCriteriaBuilder();
		CriteriaQuery<Long> criteriaQuery = criteriaBuilder.createQuery(Long.class);
		criteriaQuery.select(criteriaBuilder.count(criteriaQuery.from(searchedClass)));
		TypedQuery<Long> typedQuery = this.createLongQuery(criteriaQuery);
		return typedQuery.getSingleResult();
	}

	/**
	 * @return the criteria builder
	 */
	public CriteriaBuilder getCriteriaBuilder() {
		return this.getStorageService().getCriteriaBuilder();
	}

	/**
	 * @return the storage service
	 */
	public StorageService getStorageService() {
		if (this.storageService == null) {
			throw new NullPointerException("StorageService not initialized!");
		}
		return this.storageService;
	}

	@Override
	public E merge(E entity) {
		try {
			return this.getStorageService().getEntityManager().merge(entity);
		} catch (Exception e) {
			this.getLogger().log(Level.SEVERE, "Error merging FaktotumEntity", e);
			throw e;
		}
	}

	@Override
	public void persist(E entity) {
		try {
			this.getStorageService().getEntityManager().persist(entity);
		} catch (Exception e) {
			this.getLogger().log(Level.SEVERE, "Error persisting FaktotumEntity", e);
			throw e;
		}
	}

	@Override
	public void remove(E entity) {
		this.getStorageService().getEntityManager().remove(entity);
	}
}