Package org.apache.tinkerpop.gremlin.process.traversal.step.util

Class SupplyingBarrierStep<S,E>

java.lang.Object
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep<S,E>
org.apache.tinkerpop.gremlin.process.traversal.step.util.SupplyingBarrierStep<S,E>
All Implemented Interfaces:
Serializable, Cloneable, Iterator<Traverser.Admin<E>>, Step<S,E>, Barrier<Boolean>, MemoryComputing<Boolean>
Direct Known Subclasses:
SideEffectCapStep
public abstract class SupplyingBarrierStep<S,E> extends AbstractStep<S,E> implements Barrier<Boolean>
Author:
Marko A. Rodriguez (http://markorodriguez.com)
See Also:

  • Constructor Details

    • SupplyingBarrierStep

      public SupplyingBarrierStep(Traversal.Admin traversal)

  • Method Details

    • supply

      protected abstract E supply()

    • addStarts

      public void addStarts(Iterator<Traverser.Admin<S>> starts)
      Description copied from interface: Step
      Add an iterator of Traverser.Admin objects of type S to the step.
      Specified by:
      addStarts in interface Step<S,E>
      Overrides:
      addStarts in class AbstractStep<S,E>
      Parameters:
      starts - The iterator of objects to add

    • addStart

      public void addStart(Traverser.Admin<S> start)
      Description copied from interface: Step
      Add a single Traverser.Admin to the step.
      Specified by:
      addStart in interface Step<S,E>
      Overrides:
      addStart in class AbstractStep<S,E>
      Parameters:
      start - The traverser to add

    • reset

      public void reset()
      Description copied from interface: Step
      Reset the state of the step such that it has no incoming starts. Internal states are to be reset, but any sideEffect data structures are not to be recreated.
      Specified by:
      reset in interface Step<S,E>
      Overrides:
      reset in class AbstractStep<S,E>

    • processNextStart

      public Traverser.Admin<E> processNextStart()
      Specified by:
      processNextStart in class AbstractStep<S,E>

    • clone

      public SupplyingBarrierStep<S,E> clone()
      Description copied from interface: Step
      Cloning is used to duplicate steps for the purpose of traversal optimization and OLTP replication. When cloning a step, it is important that the steps, the cloned step is equivalent to the state of the step when Step.reset() is called. Moreover, the previous and next steps should be set to EmptyStep.
      Specified by:
      clone in interface Step<S,E>
      Overrides:
      clone in class AbstractStep<S,E>
      Returns:
      The cloned step

    • processAllStarts

      public void processAllStarts()
      Description copied from interface: Barrier
      Process all left traversers by do not yield the resultant output. This method is useful for steps like ReducingBarrierStep, where traversers can be processed "on the fly" and thus, reduce memory consumption.
      Specified by:
      processAllStarts in interface Barrier<S>

    • hasNextBarrier

      public boolean hasNextBarrier()
      Description copied from interface: Barrier
      Whether or not the step has an accessible barrier.
      Specified by:
      hasNextBarrier in interface Barrier<S>
      Returns:
      whether a barrier exists or not

    • nextBarrier

      public Boolean nextBarrier() throws NoSuchElementException
      Description copied from interface: Barrier
      Get the next barrier within this step. Barriers from parallel steps can be the be merged to create a single step with merge barriers.
      Specified by:
      nextBarrier in interface Barrier<S>
      Returns:
      the next barrier of the step
      Throws:
      NoSuchElementException

    • addBarrier

      public void addBarrier(Boolean barrier)
      Description copied from interface: Barrier
      Add a barrier to the step. This typically happens when multiple parallel barriers need to become one barrier at a single step.
      Specified by:
      addBarrier in interface Barrier<S>
      Parameters:
      barrier - the barrier to merge in

    • done

      public void done()
      Description copied from interface: Barrier
      A way to hard set that the barrier is complete. This is necessary when parallel barriers don't all have barriers and need hard resetting. The default implementation does nothing.
      Specified by:
      done in interface Barrier<S>

    • getMemoryComputeKey

      public MemoryComputeKey<Boolean> getMemoryComputeKey()
      Description copied from interface: MemoryComputing
      The MemoryComputeKey that will be used by this step.
      Specified by:
      getMemoryComputeKey in interface MemoryComputing<S>
      Returns:
      the MemoryComputeKey to use