javafxjava.util.concurrent

Canceling JavaFX Service when in SCHEDULED state

I am trying to cancel my JavaFX Service using the cancel() method. Before I call cancel(), I check the Worker state.

System.out.println(service.getState());

System.out.println(service.cancel());

The cancel() method persistently fails when the Worker is in the SCHEDULED state. cancel() returns false, and the Worker proceeds to the RUNNUNG state, before terminating as SUCCEEDED.

I cant find anything in the docs about cancel() not affecting a SCHEDULED Worker. Is this normal behaviour?

Solution

  • If this is the case, then you should file a bug report, as the behavior you describe directly contradicts the specified behavior in the Worker.State javadoc.

    A Worker may be cancelled when READY, SCHEDULED, or RUNNING, in which case the final status will be CANCELLED. When a Worker is cancelled in one of these circumstances it will transition immediately to the CANCELLED state.

    Could it be some concurrency problem with my Task?

    I want somebody to answer questions about potential issues in your code, you need to edit your question to provide an MCVE.

    Is there any sources that outlines reasons for why a cancel() would fail?

    javafx-src.zip is included in the Oracle Java 8 JRE, you can investigate the source code to determine some of the reasons for it's behavior.