/*

 * Copyright (c) 2016, 2018, 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 point in time.

 *

 * @since 9

 */

@MetadataDefinition

@ContentType

@Label("Timestamp")

@Description("A point in time")

@Retention(RetentionPolicy.RUNTIME)

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

public @interface Timestamp {

    /**

     * The unit for the difference, measured in milliseconds, between the current

     * time and midnight, January 1, 1970 UTC.

     */

    public final static String MILLISECONDS_SINCE_EPOCH = "MILLISECONDS_SINCE_EPOCH";

    /**

     * The unit for the number of ticks that have transpired since some arbitrary

     * starting date.

     */

    public final static String TICKS = "TICKS";

    /**

     * Unit for the time stamp.

     *

     * @return time stamp unit, not {@code null}

     */

    String value() default Timestamp.MILLISECONDS_SINCE_EPOCH;

}