1 /*
   2  * Copyright (c) 2016, 2019, 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.jfr;
  27 
  28 import java.lang.annotation.ElementType;
  29 import java.lang.annotation.Retention;
  30 import java.lang.annotation.RetentionPolicy;
  31 import java.lang.annotation.Target;
  32 
  33 /**
  34  * Event field annotation, signifies that the value is a duration.
  35  *
  36  * @since 9
  37  */
  38 @MetadataDefinition
  39 @ContentType
  40 @Label("Timespan")
  41 @Description("A duration, measured in nanoseconds by default")
  42 @Retention(RetentionPolicy.RUNTIME)
  43 @Target({ ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})
  44 public @interface Timespan {
  45     /**
  46      * Unit for ticks.
  47      */
  48     public static final String TICKS = "TICKS";
  49     /**
  50      * Unit for seconds.
  51      */
  52     public static final String SECONDS = "SECONDS";
  53     /**
  54      * Unit for milliseconds.
  55      */
  56     public static final String MILLISECONDS = "MILLISECONDS";
  57     /**
  58      * Unit for nanoseconds.
  59      */
  60     public static final String NANOSECONDS = "NANOSECONDS";
  61 
  62     /**
  63      * Unit for microseconds.
  64      */
  65     public static final String MICROSECONDS = "MICROSECONDS";
  66 
  67     /**
  68      * Returns the unit of measure for the time span. By default, the unit is nanoseconds.
  69      *
  70      * @return the time span unit, default {@code #NANOSECONDS}, not {@code null}
  71      */
  72     String value() default NANOSECONDS;
  73 }