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package jdk.jfr;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

Annotation that specifies that a method in an event class should be used to filter out events.

For the method to be valid it must return a SettingControl and only have one parameter, which should be a non-abstract subclass of SettingControl

The return value of the method specifies whether the event is to be written to the Flight Recorder system or not.

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

 class HelloWorld extend Event { @Label("Message"); String message; @SettingDefinition; @Label("Message Filter"); public boolean filter(RegExpControl regExp) { return regExp.matches(message); } } 
For an example of how the setting controls are defined, see SettingControl.
See Also:
Since:9
/** * Annotation that specifies that a method in an event class should be used to * filter out events. * <p> * For the method to be valid it must return a {@code SettingControl} and only have one * parameter, which should be a non-abstract subclass of {@link SettingControl} * <p> * The return value of the method specifies whether the event is to be * written to the Flight Recorder system or not. * <p> * The following example shows how to annotate a method in an event class. * * <pre> * <code> * class HelloWorld extend Event { * * {@literal @}Label("Message"); * String message; * * {@literal @}SettingDefinition; * {@literal @}Label("Message Filter"); * public boolean filter(RegExpControl regExp) { * return regExp.matches(message); * } * } * </code> * </pre> * * For an example of how the setting controls are defined, see * {@link SettingControl}. * * @see SettingControl * * @since 9 */
@Retention(RetentionPolicy.RUNTIME) @Target({ ElementType.METHOD }) public @interface SettingDefinition { }