ChronoSingleThread.java

/*
 * Class:        ChronoSingleThread
 * Description:  Compute the CPU time for a single thread
 * Environment:  Java
 * Software:     SSJ 
 * Copyright (C) 2001  Pierre L'Ecuyer and Universite de Montreal
 * Organization: DIRO, Universite de Montreal
 * @author       Éric Buist
 * @since
 *
 *
 * 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 umontreal.ssj.util;
 
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadMXBean;

public class ChronoSingleThread extends AbstractChrono {
   private long myThreadId;
   static ThreadMXBean threadMXBean = null;
 
   protected void getTime(long[] tab) {
      long rawTime = getTime();
      final long DIV = 1000000000L;
      long seconds = rawTime / DIV;
      long micros = (rawTime % DIV) / 1000L;
      tab[0] = seconds;
      tab[1] = micros;
   }
 
   protected long getTime() {
      if (threadMXBean == null) {
         // We use lazy initialization to avoid a potential exception being wrapped into
         // a confusing
         // ExceptionInInitializerError. That would happen if this initialization was in
         // a static block instead of
         // in this method.
         threadMXBean = ManagementFactory.getThreadMXBean();
         if (!threadMXBean.isThreadCpuTimeEnabled())
            // Call this only when necessary, because this can throw a SecurityException if
            // run under a security manager.
            threadMXBean.setThreadCpuTimeEnabled(true);
      }
      long time = threadMXBean.getThreadCpuTime(myThreadId);
      return time < 0 ? 0 : time;
   }

   public ChronoSingleThread() {
      super();
      myThreadId = Thread.currentThread().getId();
      init();
   }

   public ChronoSingleThread(Thread inThread) {
      super();
      myThreadId = inThread.getId();
      init();
   }
 
}