package com.atlassian.vcache.internal.core.metrics;
   
   import java.util.function.LongConsumer;
   
   import static java.util.Objects.requireNonNull;
   
   /**
    * Utility timer for measuring the elapsed time using {@link System#nanoTime()}. Timing is started when the
    * instance is created, and stopped when {@link #close()} is called.
   *
   * @since 1.0.0
   */
  public class ElapsedTimer implements AutoCloseable {
      private final long startTime;
      private final LongConsumer handler;
  
      /**
       * Create an instance with a handler to be called with the total elapsed time.
       *
       * @param handler called when the timer has been closed.
       */
      public ElapsedTimer(LongConsumer handler) {
          this.startTime = System.nanoTime();
          this.handler = requireNonNull(handler);
      }
  
      @Override
      public void close() {
          handler.accept(System.nanoTime() - startTime);
      }
  }