code: /**
   * Copyright 2014 Alexey Ragozin
   *
   * 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.
   */
  package org.gridkit.jvmtool;
  
  import org.gridkit.lab.jvm.perfdata.JStatData;
  import org.gridkit.lab.jvm.perfdata.JStatData.TickCounter;
  
  public class PerfCounterGcCpuUsageMonitor implements GcCpuUsageMonitor {
  
      TickCounter gc0;
      TickCounter gc1;
  
      public PerfCounterGcCpuUsageMonitor(long pid) {
          JStatData jd = JStatData.connect(pid);
          gc0 = (TickCounter) jd.getAllCounters().get("sun.gc.collector.0.time");
          gc1 = (TickCounter) jd.getAllCounters().get("sun.gc.collector.1.time");
      }
  
      public boolean isAvailable() {
          return gc0 != null && gc1 != null;
      }
  
      @Override
      public long getYoungGcCpu() {
          return gc0 == null ? 0 : gc0.getNanos();
      }
  
      @Override
      public long getOldGcCpu() {
          return gc1 == null ? 0 : gc1.getNanos();
      }
  }
  