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.LongCounter;
  import org.gridkit.lab.jvm.perfdata.JStatData.TickCounter;
  
  public class PerfCounterSafePointMonitor implements SafePointMonitor {
  
      LongCounter safePointCount;
      TickCounter safePointTime;
      TickCounter safePointSyncTime;
  
      public PerfCounterSafePointMonitor(long pid) {
          JStatData jd = JStatData.connect(pid);
          safePointCount = (LongCounter) jd.getAllCounters().get("sun.rt.safepoints");
          safePointTime = (TickCounter) jd.getAllCounters().get("sun.rt.safepointTime");
          safePointSyncTime = (TickCounter) jd.getAllCounters().get("sun.rt.safepointSyncTime");
      }
  
      public boolean isAvailable() {
          return safePointCount != null && safePointTime != null && safePointSyncTime != null;
      }
  
      @Override
      public long getSafePointCount() {
          return safePointCount == null ? 0 : safePointCount.getLong();
      }
  
      @Override
      public long getSafePointTime() {
          return safePointTime == null ? 0 : safePointTime.getNanos();
      }
  
      @Override
      public long getSafePointSyncTime() {
          return safePointSyncTime == null ? 0 : safePointSyncTime.getNanos();
      }
  }
  