content: /*
   * 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.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import jakarta.persistence.EntityManager;
  import jakarta.persistence.NoResultException;
  import jakarta.persistence.TypedQuery;
  
  import org.apache.ambari.server.orm.RequiresSession;
  import org.apache.ambari.server.orm.entities.HostEntity;
  import org.apache.ambari.server.orm.entities.StageEntity;
  
  import com.google.inject.Inject;
  import com.google.inject.Provider;
  import com.google.inject.Singleton;
  import com.google.inject.persist.Transactional;
  
  @Singleton
  public class HostDAO {
  
    @Inject
    Provider<EntityManager> entityManagerProvider;
  
    /**
     * Looks for Host by ID
     * @param hostId ID of Host
     * @return Found entity or NULL
     */
    @RequiresSession
    public HostEntity findById(long hostId) {
      return entityManagerProvider.get().find(HostEntity.class, hostId);
    }
  
    @RequiresSession
    public HostEntity findByName(String hostName) {
      TypedQuery<HostEntity> query = entityManagerProvider.get().createNamedQuery(
          "HostEntity.findByHostName", HostEntity.class);
      query.setParameter("hostName", hostName);
      try {
        return query.getSingleResult();
      } catch (NoResultException ignored) {
        return null;
      }
    }
  
    @RequiresSession
    public List<HostEntity> findAll() {
      TypedQuery<HostEntity> query = entityManagerProvider.get().createQuery("SELECT host FROM HostEntity host", HostEntity.class);
      try {
        return query.getResultList();
      } catch (NoResultException e) {
        return Collections.emptyList();
      }
    }
  
    @RequiresSession
    public List<HostEntity> findByStage(StageEntity stageEntity) {
      TypedQuery<HostEntity> query = entityManagerProvider.get().createQuery(
          "SELECT host FROM HostEntity host " +
              "WHERE host.hostName IN (" +
              "SELECT DISTINCT host.hostName " +
              "FROM HostEntity host " +
              "JOIN host.hostRoleCommandEntities command " +
              "JOIN command.stage stage " +
              "WHERE stage=:stageEntity)", HostEntity.class);
      query.setParameter("stageEntity", stageEntity);
      try {
        return query.getResultList();
      } catch (NoResultException e) {
        return Collections.emptyList();
      }
    }
  
    /**
     * Refreshes entity state from database
     * @param hostEntity entity to refresh
     */
    @Transactional
    public void refresh(HostEntity hostEntity) {
      entityManagerProvider.get().refresh(hostEntity);
    }
  
    @Transactional
    public void create(HostEntity hostEntity) {
      entityManagerProvider.get().persist(hostEntity);
    }
  
    @Transactional
    public HostEntity merge(HostEntity hostEntity) {
      return entityManagerProvider.get().merge(hostEntity);
    }
  
    @Transactional
    public void remove(HostEntity hostEntity) {
      entityManagerProvider.get().remove(hostEntity);
    }
  
    public List<String> getHostNamesByHostIds(List<Long> hostIds) {
      List<String> hostNames = new ArrayList<>();
      if (hostIds != null) {
        for (Long hostId : hostIds) {
          HostEntity hostEntity = findById(hostId);
          hostNames.add(hostEntity.getHostName());
        }
      }
      return hostNames;
    }
  }
  