Module java.base

Class ForkJoinWorkerThread

java.lang.Object
java.lang.Thread
java.util.concurrent.ForkJoinWorkerThread
All Implemented Interfaces:
Runnable

public class ForkJoinWorkerThread
extends Thread
A thread managed by a ForkJoinPool, which executes ForkJoinTasks. This class is subclassable solely for the sake of adding functionality -- there are no overridable methods dealing with scheduling or execution. However, you can override initialization and termination methods surrounding the main task processing loop. If you do create such a subclass, you will also need to supply a custom ForkJoinPool.ForkJoinWorkerThreadFactory to use it in a ForkJoinPool.
Since:
1.7
  • Constructor Details

    • ForkJoinWorkerThread

      protected ForkJoinWorkerThread(ThreadGroup group, ForkJoinPool pool)
      Creates a ForkJoinWorkerThread operating in the given pool.
      Parameters:
      group - thread group, can be null
      pool - the pool this thread works in
      Throws:
      NullPointerException - if pool is null
      Since:
      99
    • ForkJoinWorkerThread

      protected ForkJoinWorkerThread(ForkJoinPool pool)
      Creates a ForkJoinWorkerThread operating in the given pool.
      Parameters:
      pool - the pool this thread works in
      Throws:
      NullPointerException - if pool is null
  • Method Details

    • getPool

      public ForkJoinPool getPool()
      Returns the pool hosting this thread.
      Returns:
      the pool
    • getPoolIndex

      public int getPoolIndex()
      Returns the unique index number of this thread in its pool. The returned value ranges from zero to the maximum number of threads (minus one) that may exist in the pool, and does not change during the lifetime of the thread. This method may be useful for applications that track status or collect results per-worker-thread rather than per-task.
      Returns:
      the index number
    • onStart

      protected void onStart()
      Initializes internal state after construction but before processing any tasks. If you override this method, you must invoke super.onStart() at the beginning of the method. Initialization requires care: Most fields must have legal default values, to ensure that attempted accesses from other threads work correctly even before this thread starts processing tasks.
    • onTermination

      protected void onTermination(Throwable exception)
      Performs cleanup associated with termination of this worker thread. If you override this method, you must invoke super.onTermination at the end of the overridden method.
      Parameters:
      exception - the exception causing this thread to abort due to an unrecoverable error, or null if completed normally
    • run

      public void run()
      This method is required to be public, but should never be called explicitly. It performs the main run loop to execute ForkJoinTasks.
      Specified by:
      run in interface Runnable
      Overrides:
      run in class Thread
      See Also:
      Thread.start(), Thread(ThreadGroup, Runnable, String)