/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.ambari.server.orm.dao;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.TypedQuery;
import org.apache.ambari.server.AmbariException;
import org.apache.ambari.server.orm.RequiresSession;
import org.apache.ambari.server.orm.entities.StackEntity;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import com.google.inject.persist.Transactional;
/**
* The {@link StackDAO} class is used to manage the persistence and retrieval of
* {@link StackEntity} instances.
*/
@Singleton
public class StackDAO {
/**
* JPA entity manager
*/
@Inject
private Provider<EntityManager> entityManagerProvider;
/**
* DAO utilities for dealing mostly with {@link TypedQuery} results.
*/
@Inject
private DaoUtils daoUtils;
/**
* Gets a stack with the specified ID.
*
* @param stackId
* the ID of the stack to retrieve.
* @return the stack or {@code null} if none exists.
*/
@RequiresSession
public StackEntity findById(long stackId) {
return entityManagerProvider.get().find(StackEntity.class, stackId);
}
/**
* Gets all of the defined stacks.
*
* @return all of the stacks loaded from resources or an empty list (never
* {@code null}).
*/
@RequiresSession
public List<StackEntity> findAll() {
TypedQuery<StackEntity> query = entityManagerProvider.get().createNamedQuery(
"StackEntity.findAll", StackEntity.class);
return daoUtils.selectList(query);
}
/**
* Gets the stack that matches the specified name and version.
*
* @return the stack matching the specified name and version or {@code null}
* if none.
*/
@RequiresSession
public StackEntity find(String stackName, String stackVersion) {
TypedQuery<StackEntity> query = entityManagerProvider.get().createNamedQuery(
"StackEntity.findByNameAndVersion", StackEntity.class);
query.setParameter("stackName", stackName);
query.setParameter("stackVersion", stackVersion);
return daoUtils.selectOne(query);
}
/**
* Persists a new stack instance.
*
* @param stack
* the stack to persist (not {@code null}).
*/
@Transactional
public void create(StackEntity stack)
throws AmbariException {
EntityManager entityManager = entityManagerProvider.get();
entityManager.persist(stack);
}
/**
* Refresh the state of the stack instance from the database.
*
* @param stack
* the stack to refresh (not {@code null}).
*/
@Transactional
public void refresh(StackEntity stack) {
entityManagerProvider.get().refresh(stack);
}
/**
* Merge the speicified stack with the existing stack in the database.
*
* @param stack
* the stack to merge (not {@code null}).
* @return the updated stack with merged content (never {@code null}).
*/
@Transactional
public StackEntity merge(StackEntity stack) {
return entityManagerProvider.get().merge(stack);
}
/**
* Creates or updates the specified entity. This method will check
* {@link StackEntity#getStackId()} in order to determine whether the entity
* should be created or merged.
*
* @param stack
* the stack to create or update (not {@code null}).
*/
public void createOrUpdate(StackEntity stack)
throws AmbariException {
if (null == stack.getStackId()) {
create(stack);
} else {
merge(stack);
}
}
/**
* Removes the specified stack and all related clusters, services and
* components.
*
* @param stack
* the stack to remove.
*/
@Transactional
public void remove(StackEntity stack) {
EntityManager entityManager = entityManagerProvider.get();
stack = findById(stack.getStackId());
if (null != stack) {
entityManager.remove(stack);
}
}
}