/*

 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jfr;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

/**

 * Event field annotation, specifies that the value is a duration.

 *

 * @since 8

 */

@MetadataDefinition

@ContentType

@Label("Timespan")

@Description("A duration, measured in nanoseconds by default")

@Retention(RetentionPolicy.RUNTIME)

@Target({ ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})

public @interface Timespan {

    /**

     * Unit for ticks.

     */

    public static final String TICKS = "TICKS";

    /**

     * Unit for seconds.

     */

    public static final String SECONDS = "SECONDS";

    /**

     * Unit for milliseconds.

     */

    public static final String MILLISECONDS = "MILLISECONDS";

    /**

     * Unit for nanoseconds.

     */

    public static final String NANOSECONDS = "NANOSECONDS";

    /**

     * Unit for microseconds.

     */

    public static final String MICROSECONDS = "MICROSECONDS";

    /**

     * Returns the unit of measure for the time span.

     * <p>

     * By default, the unit is nanoseconds.

     *

     * @return the time span unit, default {@code #NANOSECONDS}, not {@code null}

     */

    String value() default NANOSECONDS;

}