/**
* JBoss, Home of Professional Open Source
* Copyright Red Hat, Inc., and individual contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jboss.aerogear.unifiedpush.jpa.dao.impl;
import java.util.List;
import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.Query;
import javax.persistence.LockModeType;
import javax.persistence.TypedQuery;
import org.hibernate.Session;
import org.jboss.aerogear.unifiedpush.dao.GenericBaseDao;
public abstract class JPABaseDao<T, K> implements GenericBaseDao<T, K> {
@Inject
protected EntityManager entityManager;
/**
* Hook to manually inject an EntityManager.
*
* @param entityManager the EntityManager for this DAO class
*/
public void setEntityManager(EntityManager entityManager) {
this.entityManager = entityManager;
}
protected TypedQuery<T> createQuery(String jpql) {
return entityManager.createQuery(jpql, getType());
}
protected Query createUntypedQuery(String jpql) {
return entityManager.createQuery(jpql);
}
protected <O> TypedQuery<O> createQuery(String jpql, Class<O> type) {
return entityManager.createQuery(jpql, type);
}
protected org.hibernate.Query createHibernateQuery(String hql) {
Session session = (Session) entityManager.getDelegate();
return session.createQuery(hql);
}
//because you can't do T.class
public abstract Class<T> getType();
@Override
public T find(K id) {
return entityManager.find(getType(), id);
}
@Override
public void create(T entity) {
entityManager.persist(entity);
}
@Override
public void update(T entity) {
entityManager.merge(entity);
entityManager.flush();
}
/**
* Pessimistic write lock on entity
*/
@Override
public void lock(T entity) {
entityManager.lock(entity, LockModeType.PESSIMISTIC_WRITE);
}
@Override
public void delete(T entity) {
if (entity != null) {
// making sure the entity in question,
// is really part of this transaction
if (! entityManager.contains(entity)) {
entity = entityManager.merge(entity);
}
entityManager.remove(entity);
}
}
/**
* Write pending objects to the database and
* clear session-scoped cache
*/
@Override
public void flushAndClear() {
entityManager.flush();
entityManager.clear();
}
protected T getSingleResultForQuery(TypedQuery<T> query) {
List<T> result = query.getResultList();
if (!result.isEmpty()) {
return result.get(0);
} else {
return null;
}
}
}