org.apache.tinkerpop.gremlin.process.traversal

## Interface Traverser.Admin<T>

- All Superinterfaces:
    org.apache.tinkerpop.gremlin.structure.util.Attachable<T>, Cloneable, Comparable<Traverser<T>>, Serializable, Traverser<T>
  Enclosing interface:
    Traverser<T>

      public static interface Traverser.Admin<T>
      extends Traverser<T>, org.apache.tinkerpop.gremlin.structure.util.Attachable<T>

  The methods in System.Traverser are useful to underlying Step and Traversal implementations. They should not be accessed by the user during lambda-based manipulations.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traverser

      `Traverser.Admin<T>`

    - ### Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.structure.util.Attachable

      `org.apache.tinkerpop.gremlin.structure.util.Attachable.Exceptions, org.apache.tinkerpop.gremlin.structure.util.Attachable.Method`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static String` | `HALT`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods Default Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addLabels(Set<String> labels)`
    `T` | `attach(Function<org.apache.tinkerpop.gremlin.structure.util.Attachable<T>,T> method)` Regenerate the detached traverser given its location at a particular vertex.
    `Traverser.Admin<T>` | `detach()` Prepare the traverser for migration across a JVM boundary.
    `void` | `dropLabels(Set<String> labels)` Drop all path information associated with specified labels.
    `void` | `dropPath()` Drop the path of the traverser.
    `TraversalSideEffects` | `getSideEffects()` Get the sideEffects associated with the traversal of the traverser.
    `String` | `getStepId()` Get the step id of where the traverser is located.
    `Set<String>` | `getTags()` Get the tags associated with the traverser.
    `void` | `incrLoops()` Increment the number of times the traverser has gone through a looping section of traversal.
    `void` | `initialiseLoops(String stepLabel, String loopName)` Initialise a loop by setting up the looping construct.
    `default boolean` | `isHalted()` If the traverser has "no future" then it is done with its lifecycle.
    `void` | `keepLabels(Set<String> labels)` Drop all path information not associated with specified labels.
    `void` | `merge(Traverser.Admin<?> other)` When two traversers are have equality with each other, then they can be merged.
    `void` | `resetLoops()` Set the number of times the traverser has gone through a loop back to 0.
    `void` | `set(T t)` Set the current object location of the traverser.
    `void` | `setBulk(long count)` Set the number of traversers represented by this traverser.
    `void` | `setSideEffects(TraversalSideEffects sideEffects)` Set the sideEffects of the `Traversal`.
    `void` | `setStepId(String stepId)` Set the step id of where the traverser is located.
    `Traverser.Admin<T>` | `split()` Generate a sibling traverser of the current traverser with a full copy of all state within the sibling.
    `<R> Traverser.Admin<R>` | `split(R r, Step<T,R> step)` Generate a child traverser of the current traverser for current as step and new object location.

    - ### Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traverser

      `asAdmin, bulk, clone, compareTo, get, loops, loops, path, path, path, sack, sack, sideEffects, sideEffects`

    - ### Methods inherited from interface org.apache.tinkerpop.gremlin.structure.util.Attachable

      `get`

- - ### Field Detail

    - #### HALT

          static final String HALT

      See Also:
        Constant Field Values

  - ### Method Detail

    - #### merge

          void merge(Traverser.Admin<?> other)

      When two traversers are have equality with each other, then they can be merged. This method is used to merge the traversers into a single traverser. This is used for optimization where instead of enumerating all traversers, they can be counted.
      Parameters:
        `other` - the other traverser to merge into this traverser. Once merged, the other can be garbage collected.

    - #### split

          <R> Traverser.Admin<R> split(R r,
                                       Step<T,R> step)

      Generate a child traverser of the current traverser for current as step and new object location. The child has the path history, future, and loop information of the parent. The child extends that path history with the current as and provided R-object.
      Type Parameters:
        `R` - The current object type of the child
      Parameters:
        `r` - The current object of the child
        `step` - The step yielding the split
      Returns:
        The split traverser

    - #### split

          Traverser.Admin<T> split()

      Generate a sibling traverser of the current traverser with a full copy of all state within the sibling.
      Returns:
        The split traverser

    - #### addLabels

          void addLabels(Set<String> labels)

    - #### keepLabels

          void keepLabels(Set<String> labels)

      Drop all path information not associated with specified labels. This is an optimization method that allows a traverser to save memory and increase the likelihood of bulking.
      Parameters:
        `labels` - the labels to keep path information for.

    - #### dropLabels

          void dropLabels(Set<String> labels)

      Drop all path information associated with specified labels. This is an optimization method that allows a traverser to save memory and increase the likelihood of bulking.
      Parameters:
        `labels` - the labels to drop path information for.

    - #### dropPath

          void dropPath()

      Drop the path of the traverser. This is an optimization method that allows a traverser to save memory and increase the likelihood of bulking.

    - #### set

          void set(T t)

      Set the current object location of the traverser.
      Parameters:
        `t` - The current object of the traverser

    - #### initialiseLoops

          void initialiseLoops(String stepLabel,
                               String loopName)

      Initialise a loop by setting up the looping construct. The step label is important to create a stack of loop counters when within a nested context. If the provided label is not the same as the current label on the stack, add a new loop counter. The loopName can be used to refer to the loops counter via the `LoopsStep`
      Parameters:
        `stepLabel` - the label of the step that is being set-up.
        `loopName` - the user defined name for referencing the loop counter or null if not set

    - #### incrLoops

          void incrLoops()

      Increment the number of times the traverser has gone through a looping section of traversal.

    - #### resetLoops

          void resetLoops()

      Set the number of times the traverser has gone through a loop back to 0. When a traverser exits a looping construct, this method should be called. In a nested loop context, the highest stack loop counter should be removed.

    - #### getStepId

          String getStepId()

      Get the step id of where the traverser is located. This is typically used in multi-machine systems that require the movement of traversers between different traversal instances.
      Returns:
        The future step for the traverser

    - #### setStepId

          void setStepId(String stepId)

      Set the step id of where the traverser is located. If the future is `HALT`, then `isHalted()` is true.
      Parameters:
        `stepId` - The future step of the traverser

    - #### isHalted

          default boolean isHalted()

      If the traverser has "no future" then it is done with its lifecycle. This does not mean that the traverser is "dead," only that it has successfully passed through a `Traversal`.
      Returns:
        Whether the traverser is done executing or not

    - #### setBulk

          void setBulk(long count)

      Set the number of traversers represented by this traverser.
      Parameters:
        `count` - the number of traversers

    - #### detach

          Traverser.Admin<T> detach()

      Prepare the traverser for migration across a JVM boundary.
      Returns:
        The deflated traverser

    - #### attach

          T attach(Function<org.apache.tinkerpop.gremlin.structure.util.Attachable<T>,T> method)

      Regenerate the detached traverser given its location at a particular vertex.
      Specified by:
        `attach` in interface `org.apache.tinkerpop.gremlin.structure.util.Attachable<T>`
      Parameters:
        `method` - The method by which to attach a `Traverser` to an vertex.
      Returns:
        The inflated traverser

    - #### setSideEffects

          void setSideEffects(TraversalSideEffects sideEffects)

      Set the sideEffects of the `Traversal`. Given that traversers can move between machines, it may be important to re-set this when the traverser crosses machine boundaries.
      Parameters:
        `sideEffects` - the sideEffects of the traversal.

    - #### getSideEffects

          TraversalSideEffects getSideEffects()

      Get the sideEffects associated with the traversal of the traverser.
      Returns:
        the traversal sideEffects of the traverser

    - #### getTags

          Set<String> getTags()

      Get the tags associated with the traverser. Tags are used to categorize historic behavior of a traverser. The returned set is mutable.
      Returns:
        the set of tags associated with the traverser.

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