Java tutorial
package com.devicehive.dao.rdbms; /* * #%L * DeviceHive Dao RDBMS Implementation * %% * Copyright (C) 2016 DataArt * %% * 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. * #L% */ import com.devicehive.configuration.Constants; import org.springframework.context.annotation.Profile; import org.springframework.stereotype.Repository; import org.springframework.transaction.annotation.Propagation; import org.springframework.transaction.annotation.Transactional; import javax.persistence.*; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import java.io.Serializable; import java.util.Optional; @Repository public class RdbmsGenericDao { public static final String CACHEABLE = "org.hibernate.cacheable"; public static final String RETRIEVE_MODE = "javax.persistence.cache.retrieveMode"; public static final String STORE_MODE = "javax.persistence.cache.storeMode"; @PersistenceContext(unitName = Constants.PERSISTENCE_UNIT) private EntityManager em; @Transactional(propagation = Propagation.SUPPORTS, readOnly = true) public <T extends Serializable> T find(Class<T> entityClass, Object primaryKey) { return em.find(entityClass, primaryKey); } @Transactional(propagation = Propagation.MANDATORY) public <T extends Serializable> void persist(T entity) { em.persist(entity); } @Transactional(propagation = Propagation.MANDATORY) public <T extends Serializable> T merge(T entity) { return em.merge(entity); } @Transactional(propagation = Propagation.MANDATORY) public <T extends Serializable> void remove(T entity) { em.remove(entity); } public <T extends Serializable> T reference(Class<T> entityClass, Object primaryKey) { return em.getReference(entityClass, primaryKey); } public <T extends Serializable> TypedQuery<T> createNamedQuery(Class<T> entityClass, String queryName, Optional<CacheConfig> cacheConfig) { TypedQuery<T> query = em.createNamedQuery(queryName, entityClass); cacheQuery(query, cacheConfig); return query; } public Query createNamedQuery(String queryName, Optional<CacheConfig> cacheConfig) { Query query = em.createNamedQuery(queryName); cacheQuery(query, cacheConfig); return query; } public void cacheQuery(Query query, Optional<CacheConfig> cacheConfig) { if (cacheConfig.isPresent()) { query.setHint(CACHEABLE, true); query.setHint(RETRIEVE_MODE, cacheConfig.get().getRetrieveMode()); query.setHint(STORE_MODE, cacheConfig.get().getStoreMode()); } } public CriteriaBuilder criteriaBuilder() { return em.getCriteriaBuilder(); } public <T extends Serializable> TypedQuery<T> createQuery(CriteriaQuery<T> criteriaQuery) { return em.createQuery(criteriaQuery); } }