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.state.services;
  
  import java.util.concurrent.TimeUnit;
  
  import org.apache.ambari.annotations.Experimental;
  import org.apache.ambari.annotations.ExperimentalFeature;
  import org.apache.ambari.server.AmbariService;
  import org.apache.ambari.server.configuration.Configuration;
  import org.apache.ambari.server.orm.dao.AlertsDAO;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.common.util.concurrent.AbstractScheduledService;
  import com.google.inject.Inject;
  
  /**
   * The {@link CachedAlertFlushService} is used to periodically flush cached
   * alert data to the database. This service is controlled by
   * {@link Configuration#isAlertCacheEnabled()} and
   * {@link Configuration#getAlertCacheFlushInterval()}.
   */
  @AmbariService
  @Experimental(feature = ExperimentalFeature.ALERT_CACHING)
  public class CachedAlertFlushService extends AbstractScheduledService {
  
    /**
     * Logger.
     */
    private final static Logger LOG = LoggerFactory.getLogger(CachedAlertFlushService.class);
  
    /**
     * Configuration.
     */
    @Inject
    private Configuration m_configuration;
  
    /**
     * Used for flushing cached entities to the database.
     */
    @Inject
    private AlertsDAO m_alertsDAO;
  
    /**
     * {@inheritDoc}
     */
    @Override
    protected Scheduler scheduler() {
      int flushIntervalInMinutes = m_configuration.getAlertCacheFlushInterval();
      return Scheduler.newFixedDelaySchedule(flushIntervalInMinutes, flushIntervalInMinutes,
          TimeUnit.MINUTES);
    }
  
    /**
     * {@inheritDoc}
     * <p/>
     * Invokes {@link #stop()} if not enabled.
     */
    @Override
    protected void startUp() throws Exception {
      boolean enabled = m_configuration.isAlertCacheEnabled();
      if (!enabled) {
        stopAsync();
      }
    }
  
    /**
     * {@inheritDoc}
     * <p/>
     * Flushes cached alerts to the database.
     */
    @Override
    protected void runOneIteration() throws Exception {
      try {
        LOG.info("Flushing cached alerts to the database");
        m_alertsDAO.flushCachedEntitiesToJPA();
      } catch (Exception exception) {
        LOG.error("Unable to flush cached alerts to the database", exception);
      }
    }
  }
  