/*
    * 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.hadoop.chukwa.datacollection.agent.metrics;
  
  import org.apache.hadoop.metrics.MetricsContext;
  import org.apache.hadoop.metrics.MetricsRecord;
  import org.apache.hadoop.metrics.MetricsUtil;
  import org.apache.hadoop.metrics.Updater;
  import org.apache.hadoop.metrics.util.MetricsBase;
  import org.apache.hadoop.metrics.util.MetricsIntValue;
  import org.apache.hadoop.metrics.util.MetricsRegistry;
  import org.apache.hadoop.metrics.util.MetricsTimeVaryingInt;
  
  public class AgentMetrics implements Updater {
    public static final AgentMetrics agentMetrics = new AgentMetrics("chukwaAgent", "metrics");
    
    public MetricsRegistry registry = new MetricsRegistry();
    private MetricsRecord metricsRecord;
    private AgentActivityMBean agentActivityMBean;
  
    public MetricsIntValue adaptorCount =
      new MetricsIntValue("adaptorCount", registry,"number of new adaptor");
  
    public MetricsTimeVaryingInt addedAdaptor =
      new MetricsTimeVaryingInt("addedAdaptor", registry,"number of added adaptor");
    
    public MetricsTimeVaryingInt removedAdaptor =
      new MetricsTimeVaryingInt("removedAdaptor", registry,"number of removed adaptor");
    
    /** Creates a new instance of AgentMetrics 
     * @param processName is jvm name of agent process
     * @param recordName is mbean record name
     **/
    public AgentMetrics(String processName, String recordName) {
        MetricsContext context = MetricsUtil.getContext(processName);
        metricsRecord = MetricsUtil.createRecord(context, recordName);
        metricsRecord.setTag("process", processName);
        agentActivityMBean = new AgentActivityMBean(registry, recordName);
        context.registerUpdater(this);
        
    }
  
  
    /**
     * Since this object is a registered updater, this method will be called
     * periodically, e.g. every 5 seconds.
     */
    public void doUpdates(MetricsContext unused) {
      synchronized (this) {
        for (MetricsBase m : registry.getMetricsList()) {
          m.pushMetric(metricsRecord);
        }
      }
      metricsRecord.update();
    }
  
    public void shutdown() {
      if (agentActivityMBean != null)
        agentActivityMBean.shutdown();
    }
  
  }