org.jikesrvm.adaptive.measurements.listeners
Class Listener

java.lang.Object
  org.jikesrvm.adaptive.measurements.listeners.Listener

Direct Known Subclasses:

ContextListener, MethodListener, NullListener

public abstract class Listener
extends Object

A Listener object is invoked when online measurement information needs to be collected.

This class does not define the update() method, the call back method from the runtime when a sample should be taken. The expectation is that immediately derived classes define an interface to the update() method from which classes may be further derived.

CONSTRAINTS: Classes that are derived from Listener must be annotated as Uninterruptible to ensure that they are not interrupted by a thread switch. Since thread switching is disabled, listeners are expected to complete execution quickly, and therefore, must do a minimal amount of work.

active

private boolean active

Is the listener active or passive?

organizer

private Organizer organizer

the associated organizer

Listener

public Listener()

report

public abstract void report()

Entry point to dump what has been collected.

isActive

public final boolean isActive()

Is the listener currently active (interested in getting "update" calls)

activate

public final void activate()

Transition listener to active state

passivate

public final void passivate()

Transition listener to passive state

reset

public abstract void reset()

Reset the listeners data structures in preparation of a new sampling window. This is called by the organizer after processing the samples from the old sampling window.

setOrganizer

public final void setOrganizer(Organizer organizer)

Organizer associated with this listener.

activateOrganizer

public final void activateOrganizer()

Wake up the organizer thread (if any) associated with the listener