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

Class CollectingBarrierStep<S>

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

  • Field Details

  • Constructor Details

    • CollectingBarrierStep

      public CollectingBarrierStep(Traversal.Admin traversal)

    • CollectingBarrierStep

      public CollectingBarrierStep(Traversal.Admin traversal, int maxBarrierSize)

  • Method Details

    • barrierConsumer

      public abstract void barrierConsumer(TraverserSet<S> traverserSet)

    • getRequirements

      public Set<TraverserRequirement> getRequirements()
      Description copied from interface: Step
      Provide the necessary TraverserRequirement that must be met by the traverser in order for the step to function properly. The provided default implements returns an empty set.
      Specified by:
      getRequirements in interface Step<S,S>
      Returns:
      the set of requirements

    • 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 TraverserSet<S> 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

    • getEmptyBarrier

      public TraverserSet<S> getEmptyBarrier()
      Description copied from interface: Barrier
      If a barrier is unproductive then provide an empty object suitable to the implementation which can be used to represent that state. This is important for cases like by(out().order().fold()) where the order() might filter but the fold() means the traversal is productive.
      Specified by:
      getEmptyBarrier in interface Barrier<S>

    • addBarrier

      public void addBarrier(TraverserSet<S> 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

    • processNextStart

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

    • clone

      public CollectingBarrierStep<S> 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,S>
      Overrides:
      clone in class AbstractStep<S,S>
      Returns:
      The cloned step

    • toString

      public String toString()
      Overrides:
      toString in class AbstractStep<S,S>

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class AbstractStep<S,S>

    • 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,S>
      Overrides:
      reset in class AbstractStep<S,S>

    • getMemoryComputeKey

      public MemoryComputeKey<TraverserSet<S>> 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