1 /*

     2  * Copyright (c) 2016, 2018, 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 package jdk.jfr;

    26 

    27 import java.lang.annotation.ElementType;

    28 import java.lang.annotation.Retention;

    29 import java.lang.annotation.RetentionPolicy;

    30 import java.lang.annotation.Target;

    31 

    32 /**

    33  * Annotation that specifies that a method in an event class should be used to

    34  * filter out events.

    35  * <p>

    36  * For the method to be valid it must return a {@code SettingControl} and only have one

    37  * parameter, which should be a non-abstract subclass of {@link SettingControl}

    38  * <p>

    39  * The return value of the method specifies whether the event is to be

    40  * written to the Flight Recorder system or not.

    41  * <p>

    42  * The following example shows how to annotate a method in an event class.

    43  *

    44  * <pre>

    45  * <code>

    46  * class HelloWorld extend Event {

    47  *

    48  *   {@literal @}Label("Message");

    49  *   String message;

    50  *

    51  *   {@literal @}SettingDefinition;

    52  *   {@literal @}Label("Message Filter");

    53  *   public boolean filter(RegExpControl regExp) {

    54  *     return regExp.matches(message);

    55  *   }

    56  * }

    57  * </code>

    58  * </pre>

    59  *

    60  * For an example of how the setting controls are defined, see

    61  * {@link SettingControl}.

    62  *

    63  * @see SettingControl

    64  *

    65  * @since 9

    66  */

    67 @Retention(RetentionPolicy.RUNTIME)

    68 @Target({ ElementType.METHOD })

    69 public @interface SettingDefinition {

    70 }