jfr_btrace.java

@JfrPeriodicEventHandler
// register a periodic JFR event and assing its handler to this method; the periodicity is defined in the Event itself via 'jdk.jfr.Period' annotation
public static void handleSimplePeriodic(SimplePeriodicEvent event) {
  // the handler code will be called periodically by the JFR infrastructure 
  if (event.shouldCommit()) {
    // if the event type is enabled and there is an ongoing recording set up the valued and commit the event
    event.setValue(10);
    event.commit();
  }
}

@JfrBlock(SimpleEvent.class)
// create a block containing JFR event calls; all the event types enumerated in the annotation will be automatically registered
public static void emitEvent(long bytesRead) {
  // instantiate the event
  SimpleEvent event = new SimpleEvent();
  if (event.shouldCommit()) {
    // if the event type is enabled and there is an ongoing recording set up the valued and commit the event
    event.setValue(bytesRead);
    event.commit();
  }
}