1 /*
   2  * Copyright (c) 2012, 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 package org.graalvm.compiler.debug;
  24 
  25 import java.util.concurrent.TimeUnit;
  26 
  27 /**
  28  * A timer for some activity of interest. A timer should be deployed using the try-with-resources
  29  * pattern:
  30  *
  31  * <pre>
  32  * try (TimerCloseable a = timer.start()) {
  33  *     // the code to time
  34  * }
  35  * </pre>
  36  */
  37 public interface DebugTimer {
  38 
  39     /**
  40      * Starts this timer if timing is {@linkplain Debug#isTimeEnabled() enabled} or this is an
  41      * {@linkplain #isConditional() unconditional} timer.
  42      *
  43      * @return an object that must be closed once the activity has completed to add the elapsed time
  44      *         since this call to the total for this timer
  45      */
  46     DebugCloseable start();
  47 
  48     /**
  49      * Sets a flag determining if this timer is only enabled if timing is
  50      * {@link Debug#isTimeEnabled() enabled}.
  51      */
  52     void setConditional(boolean flag);
  53 
  54     /**
  55      * Determines if this timer is only enabled if timing is {@link Debug#isTimeEnabled() enabled}.
  56      */
  57     boolean isConditional();
  58 
  59     /**
  60      * Gets the current value of this timer.
  61      */
  62     long getCurrentValue();
  63 
  64     /**
  65      * Gets the time unit of this timer.
  66      */
  67     TimeUnit getTimeUnit();
  68 
  69     /**
  70      * Gets the timer recording the amount time spent within a timed scope minus the time spent in
  71      * any nested timed scopes.
  72      *
  73      * @return null if this timer does not support flat timing
  74      */
  75     default DebugTimer getFlat() {
  76         return null;
  77     }
  78 }