/* * 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; /** * Meta annotation for defining new types of event metadata. *
* In the following example, a transaction event is defined with two * user-defined annotations, {@code @Severity} and {@code @TransactionId}. * *
*
*{@literal @}MetadataDefinition
*{@literal @}Label("Severity")
*{@literal @}Description("Value between 0 and 100 that indicates severity. 100 is most severe.")
*{@literal @}Retention(RetentionPolicy.RUNTIME)
*{@literal @}Target({ ElementType.TYPE })
* public {@literal @}interface {@literal @}Severity {
* int value() default 50;
* }
*
*{@literal @}MetadataDefinition
*{@literal @}Label("Transaction Id")
*{@literal @}Relational
*{@literal @}Retention(RetentionPolicy.RUNTIME)
*{@literal @}Target({ ElementType.FIELD })
* public {@literal @}interface {@literal @}Severity {
* }
*
*{@literal @}Severity(80)
*{@literal @}Label("Transaction Blocked");
* class TransactionBlocked extends Event {
* {@literal @}TransactionId
* {@literal @}Label("Transaction");
* long transactionId;
*
* {@literal @}TransactionId
* {@literal @}Label("Transaction Blocker");
* long transactionId;
* }
*
*
*
*
* Adding {@code @MetadataDefinition} to the declaration of {@code @Severity} and {@code @TransactionId}
* ensures the information is saved by Flight Recorder.
*
* @since 9
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE })
public @interface MetadataDefinition {
}