/*

 * 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

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 * questions.

 */

package jdk.jfr;

import java.lang.annotation.ElementType;

import java.lang.annotation.Inherited;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

/**

 * Event annotation, specifies the default duration below which an event is not

 * recorded (for example, {@code "20 ms"}).

 *

 * @since 9

 */

@MetadataDefinition

@Target({ ElementType.TYPE })

@Inherited

@Retention(RetentionPolicy.RUNTIME)

public @interface Threshold {

    /**

     * Setting name {@code "threshold"} for configuring event thresholds.

     */

    public final static String NAME = "threshold";

    /**

     * The threshold (for example, {@code "20 ms"}).

     * <p>

     * A {@code String} representation of a positive {@code Long} value followed by an

     * empty space and one of the following units:<br>

     * <br>

     * {@code "ns"} (nanoseconds)<br>

     * {@code "us"} (microseconds)<br>

     * {@code "ms"} (milliseconds)<br>

     * {@code "s"} (seconds)<br>

     * {@code "m"} (minutes)<br>

     * {@code "h"} (hours)<br>

     * {@code "d"} (days)<br>

     * <p>

     * Example values are {@code "0 ns"}, {@code "10 ms"}, and {@code "1 s"}.

     *

     * @return the threshold, default {@code "0 ns"}, not {@code null}

     */

    String value() default "0 ns";

}