Overridable method to perform an action upon impending phase advance, and to control termination. This method is invoked upon arrival of the party advancing this phaser (when all other waiting parties are dormant). If this method returns true, this phaser will be set to a final termination state upon advance, and subsequent calls to Phaser.IsTerminated will return true. Any (unchecked) Exception or Error thrown by an invocation of this method is propagated to the party attempting to advance this phaser, in which case no advance occurs.

The arguments to this method provide the state of the phaser prevailing for the current transition. The effects of invoking arrival, registration, and waiting methods on this phaser from within onAdvance are unspecified and should not be relied on.

If this phaser is a member of a tiered set of phasers, then onAdvance is invoked only for its root phaser on each advance.

To support the most common use cases, the default implementation of this method returns true when the number of registered parties has become zero as the result of a party invoking arriveAndDeregister. You can disable this behavior, thus enabling continuation upon future registrations, by overriding this method to always return false:

[Android Documentation]