# Package org.eclipse.rdf4j.federated.evaluation.union

- Class Summary
  Class | Description
  --- | ---
  ControlledWorkerUnion<T> | Execution of union tasks with `ControlledWorkerScheduler`.
  ParallelGetStatementsTask | A task implementation to retrieve statements for a given `StatementPattern` using the provided triple source.
  ParallelPreparedAlgebraUnionTask | A task implementation representing a prepared union, i.e.
  ParallelPreparedUnionTask | A task implementation representing a prepared union, i.e.
  ParallelUnionOperatorTask | A task implementation representing a UNION operator expression to be evaluated.
  ParallelUnionTask | A task implementation representing a statement expression to be evaluated.
  SynchronousWorkerUnion<T> | Synchronous execution of union tasks, i.e.
  UnionExecutorBase<T> | Base class for any parallel union executor.
  WorkerUnionBase<T> | Base class for worker unions providing convenience functions to add tasks.