org.eclipse.rdf4j.federated.evaluation.union

## Class ControlledWorkerUnion<T>

- java.lang.Object
- - org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<E,X>
  - - org.eclipse.rdf4j.common.iteration.LookAheadIteration<T,QueryEvaluationException>
    - - org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase<T>
      - - org.eclipse.rdf4j.federated.evaluation.union.UnionExecutorBase<T>
        - - org.eclipse.rdf4j.federated.evaluation.union.WorkerUnionBase<T>
          - - org.eclipse.rdf4j.federated.evaluation.union.ControlledWorkerUnion<T>

- All Implemented Interfaces:
    AutoCloseable, Runnable, CloseableIteration<T,QueryEvaluationException>, Iteration<T,QueryEvaluationException>, ParallelExecutor<T>

      public class ControlledWorkerUnion<T>
      extends WorkerUnionBase<T>

  Execution of union tasks with `ControlledWorkerScheduler`. Tasks can be added using the provided functions. Note that the union operation is to be executed with the `ParallelExecutorBase.run()` method (also threaded execution is possible). Results are then contained in this iteration.
  Author:
    Andreas Schwarte

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `awakeCount`
    `protected Phaser` | `phaser`
    `protected ControlledWorkerScheduler<T>` | `scheduler`
    `static int` | `waitingCount`

    - ### Fields inherited from class org.eclipse.rdf4j.federated.evaluation.union.WorkerUnionBase

      `tasks`

    - ### Fields inherited from class org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase

      `evaluationThread, executorId, finished, log, NEXT_EXECUTOR_ID, queryInfo, rightIter, rightQueue, strategy`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ControlledWorkerUnion(FederationEvalStrategy strategy, ControlledWorkerScheduler<T> scheduler, QueryInfo queryInfo)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `done()` Inform the controlling instance that some job is done from a different thread.
    `void` | `toss(Exception e)` Toss some exception to the controlling instance
    `protected void` | `union()` Note: this method must block until the union is executed completely.

    - ### Methods inherited from class org.eclipse.rdf4j.federated.evaluation.union.WorkerUnionBase

      `addTask`

    - ### Methods inherited from class org.eclipse.rdf4j.federated.evaluation.union.UnionExecutorBase

      `getExecutorType, performExecution`

    - ### Methods inherited from class org.eclipse.rdf4j.federated.evaluation.concurrent.ParallelExecutorBase

      `addResult, checkTimeout, getDisplayId, getId, getNextElement, getQueryInfo, handleClose, isFinished, run, toString`

    - ### Methods inherited from class org.eclipse.rdf4j.common.iteration.LookAheadIteration

      `hasNext, next, remove`

    - ### Methods inherited from class org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration

      `close, isClosed`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface org.eclipse.rdf4j.common.iteration.Iteration

      `stream`

- - ### Field Detail

    - #### waitingCount

          public static int waitingCount

    - #### awakeCount

          public static int awakeCount

    - #### scheduler

          protected final ControlledWorkerScheduler<T> scheduler

    - #### phaser

          protected final Phaser phaser

  - ### Constructor Detail

    - #### ControlledWorkerUnion

          public ControlledWorkerUnion(FederationEvalStrategy strategy,
                                       ControlledWorkerScheduler<T> scheduler,
                                       QueryInfo queryInfo)

  - ### Method Detail

    - #### union

          protected void union()
                        throws Exception

      Description copied from class: `UnionExecutorBase`
      Note: this method must block until the union is executed completely. Otherwise the result queue is marked as committed while this isn't the case. The blocking behavior in general is no problem: If you need concurrent access to the result (i.e. pipelining) just run the union in a separate thread. Access to the result iteration is synchronized.
      Specified by:
        `union` in class `UnionExecutorBase<T>`
      Throws:
        `Exception`

    - #### done

          public void done()

      Description copied from interface: `ParallelExecutor`
      Inform the controlling instance that some job is done from a different thread. In most cases this is a no-op.
      Specified by:
        `done` in interface `ParallelExecutor<T>`
      Overrides:
        `done` in class `ParallelExecutorBase<T>`

    - #### toss

          public void toss(Exception e)

      Description copied from interface: `ParallelExecutor`
      Toss some exception to the controlling instance
      Specified by:
        `toss` in interface `ParallelExecutor<T>`
      Overrides:
        `toss` in class `ParallelExecutorBase<T>`

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