Module jdk.jfr

Package jdk.jfr

Annotation Interface Enabled

@Target(TYPE)
@Retention(RUNTIME)
@Inherited
public @interface Enabled

Event annotation, determines if an event should be enabled by default.

If an event doesn't have the annotation, then by default the event is enabled.

The following example shows how the Enabled annotation can be used to create a disabled event. A disabled event will at most have the overhead of an allocation, or none if the runtime JIT compiler is able to eliminate it.

@Name("StopWatch")
@Label("Stop Watch")
@Category("Debugging")
@StackTrace(false)
@Enabled(false)
static public class StopWatchEvent extends Event {
}

public void update() {
    StopWatchEvent e = new StopWatchEvent();
    e.begin();
    ...
    e.commit();
}

The event can be enabled programmatically, or on command line when needed, for example:

java -XX:StartFlightRecording:StopWatch#enabled=true ...

Since:

9

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
boolean	value	Returns true if by default the event should be enabled, false otherwise.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAME	Setting name "enabled", signifies that the event should be recorded.

Field Details

NAME

static final String NAME

Setting name "enabled", signifies that the event should be recorded.

See Also:

• Constant Field Values

Element Details

value

boolean value

Returns true if by default the event should be enabled, false otherwise.

Returns:

true if by default the event should be enabled by default, false otherwise

Default:

true