1 /*
   2  * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package org.graalvm.compiler.debug;
  26 
  27 import java.util.concurrent.TimeUnit;
  28 
  29 /**
  30  * A timer for some activity of interest. A timer should be deployed using the try-with-resources
  31  * pattern:
  32  *
  33  * <pre>
  34  * try (TimerCloseable a = timer.start()) {
  35  *     // the code to time
  36  * }
  37  * </pre>
  38  */
  39 public interface TimerKey extends MetricKey {
  40 
  41     /**
  42      * Starts this timer.
  43      *
  44      * @return an object that must be closed once the activity has completed to add the elapsed time
  45      *         since this call to the total for this timer
  46      */
  47     DebugCloseable start(DebugContext debug);
  48 
  49     /**
  50      * Gets the current value of this timer.
  51      */
  52     long getCurrentValue(DebugContext debug);
  53 
  54     /**
  55      * Gets the time unit of this timer.
  56      */
  57     TimeUnit getTimeUnit();
  58 
  59     @Override
  60     TimerKey doc(String string);
  61 
  62     /**
  63      * Gets the timer recording the amount time spent within a timed scope minus the time spent in
  64      * any nested timed scopes.
  65      *
  66      * @return null if this timer does not support flat timing
  67      */
  68     default TimerKey getFlat() {
  69         return null;
  70     }
  71 }