Interface PushBasedPlanThread

All Superinterfaces:
Runnable, StatsProvider
All Known Implementing Classes:
ConnectorForAdditionalConsumer, PushBasedPlanThreadImplBase, PushBasedPlanThreadImplForBinaryOperator, PushBasedPlanThreadImplForNaryOperator, PushBasedPlanThreadImplForNullaryOperator, PushBasedPlanThreadImplForUnaryOperator
public interface PushBasedPlanThread extends Runnable, StatsProvider

  • Method Summary

    Modifier and Type
    Method
    Description
    PushBasedPlanThread
    addConnectorForAdditionalConsumer()
    Can be used for cases in which multiple threads consume the output produced by this thread.
    Exception
    getCauseOfFailure()
    Returns the exception that caused the execution of this task to fail (in case hasFailed() is true).
    StatsOfPushBasedPlanThread
    getStats()
     
    boolean
    hasFailed()
    Returns true if the execution of this task has failed with an exception.
    boolean
    hasMoreOutputAvailable()
    Returns true if newly-produced solution mappings are available to be obtained via transferAvailableOutput(List).
    boolean
    isCompleted()
    Returns true if the execution of this task has completed successfully, and returns false if either the execution is still running (in which case isRunning() is true) or the execution has been interrupted (in which case isRunning() is false).
    boolean
    isRunning()
    Returns true if the execution of this task is currently running; that is, the execution has started and has neither been interrupted nor completed.
    void
    transferAvailableOutput(List<SolutionMapping> transferBuffer)
    This function first clears the given list and, then, transfers the currently-available solution mappings produced by this task from an internal buffer to the given list, in the order in which the solution mappings have been produced.

    Methods inherited from interface java.lang.Runnable

    run

    Methods inherited from interface se.liu.ida.hefquin.base.utils.StatsProvider

    resetStats

  • Method Details

    • addConnectorForAdditionalConsumer

      PushBasedPlanThread addConnectorForAdditionalConsumer()
      Can be used for cases in which multiple threads consume the output produced by this thread. While one of these threads may then consume the output directly (by calling transferAvailableOutput(List)), each of the others must then consume the output via its own, separate PushBasedPlanThread instance, as set up and returned by this method. Hence, for each of these additional consuming threads, this method needs to be called. This method should be called before starting to consume the output. The use case for this are query plans that are not tree-shaped (but still DAGs), which we may have in particular for union-over-join source assignments where some of the joins have the same request operator as input (perhaps even with a filter operator on top of the request).

    • isRunning

      boolean isRunning()
      Returns true if the execution of this task is currently running; that is, the execution has started and has neither been interrupted nor completed.

    • isCompleted

      boolean isCompleted()
      Returns true if the execution of this task has completed successfully, and returns false if either the execution is still running (in which case isRunning() is true) or the execution has been interrupted (in which case isRunning() is false).

    • hasFailed

      boolean hasFailed()
      Returns true if the execution of this task has failed with an exception. The exception that caused the failed can be obtained by calling getCauseOfFailure().

    • getCauseOfFailure

      Exception getCauseOfFailure()
      Returns the exception that caused the execution of this task to fail (in case hasFailed() is true).

    • transferAvailableOutput

      void transferAvailableOutput(List<SolutionMapping> transferBuffer) throws ConsumingPushBasedPlanThreadException
      This function first clears the given list and, then, transfers the currently-available solution mappings produced by this task from an internal buffer to the given list, in the order in which the solution mappings have been produced. The internal buffer will thus be empty at the point when this function returns (but further solution mappings may still be produced by this task and placed into the buffer to be available to be transferred at the next call of this function). If the internal buffer is empty at the time when this function is called (i.e., no solution mappings are currently available to be transferred), but the task is still running (see isRunning()) and, thus, more solution mappings may still be produced, then the call of this function causes the calling thread to wait until either more solution mappings have been produced or it has become clear that no more solution mappings can be produced anymore. In the former case, the newly-produced solution mappings are transferred to the given list and the function returns. In the latter case, the function returns directly and, thus, the given list remains empty. Also, in the latter case, after the function has returned, isCompleted() will be true. If the function is called after the task has completed or failed, then the function returns directly after clearing the given list (i.e., the list will be empty after the function call). Hence, if the given list is empty after calling this function call, then the function does not need to be called anymore; this task is not going to produce more solution mappings. This function is expected to be called by (and, thus, run in the context of) the thread that consumes the solution mappings produced by this task.
      Throws:
      ConsumingPushBasedPlanThreadException

    • hasMoreOutputAvailable

      boolean hasMoreOutputAvailable()
      Returns true if newly-produced solution mappings are available to be obtained via transferAvailableOutput(List). Hence, in this case, calling transferAvailableOutput(List) would not cause the calling thread to wait.

    • getStats

      StatsOfPushBasedPlanThread getStats()
      Specified by:
      getStats in interface StatsProvider