com.tinkerpop.gremlin.process

Interface Traverser.Admin<T>

All Superinterfaces:

Attachable<Traverser.Admin<T>>, java.lang.Cloneable, java.lang.Comparable<Traverser<T>>, java.io.Serializable, Traverser<T>

All Known Implementing Classes:

AbstractPathTraverser, AbstractTraverser, B_O_P_PA_S_SE_SL_Traverser, B_O_PA_S_SE_SL_Traverser, B_O_Traverser, EmptyTraverser, O_Traverser

Enclosing interface:

Traverser<T>

public static interface Traverser.Admin<T>
extends Traverser<T>, Attachable<Traverser.Admin<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 com.tinkerpop.gremlin.process.Traverser

Traverser.Admin<T>

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	HALT

Method Summary

Modifier and Type	Method and Description
default Traverser.Admin<T>	attach(Graph graph) Traversers can not attach to graphs and thus, an UnsupportedOperationException is thrown.
Traverser.Admin<T>	attach(Vertex hostVertex) Regenerate the detached traverser given its location at a particular vertex.
Traverser.Admin<T>	detach() Prepare the traverser for migration across a JVM boundary.
TraversalSideEffects	getSideEffects() Get the sideEffects associated with the traversal of the traverser.
java.lang.String	getStepId() Get the step id of where the traverser is located.
void	incrLoops(java.lang.String stepLabel) Increment the number of times the traverser has gone through a looping section of traversal.
default boolean	isHalted() If the traverser has "no future" then it is done with its lifecycle.
void	merge(Traverser.Admin<?> other) When two traversers are Traverser#equals to 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(java.lang.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 com.tinkerpop.gremlin.process.Traverser

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

Field Detail

HALT

static final java.lang.String HALT

See Also:

Constant Field Values

Method Detail

merge

void merge(Traverser.Admin<?> other)

When two traversers are Traverser#equals to 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

set

void set(T t)

Set the current object location of the traverser.

Parameters:

t - The current object of the traverser

incrLoops

void incrLoops(java.lang.String stepLabel)

Increment the number of times the traverser has gone through a looping section of traversal. 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. If the provided label is the same as the current label on the stack, increment the loop counter.

Parameters:

stepLabel - the label of the step that is doing the incrementing

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

java.lang.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(java.lang.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 labeled 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

Traverser.Admin<T> attach(Vertex hostVertex)

Regenerate the detached traverser given its location at a particular vertex.

Specified by:

attach in interface Attachable<Traverser.Admin<T>>

Parameters:

hostVertex - The vertex that is hosting the traverser

Returns:

The inflated traverser

attach

default Traverser.Admin<T> attach(Graph graph)
                           throws java.lang.UnsupportedOperationException

Traversers can not attach to graphs and thus, an UnsupportedOperationException is thrown.

Specified by:

attach in interface Attachable<Traverser.Admin<T>>

Parameters:

graph - the graph to attach the traverser to, which it can't.

Returns:

nothing as an exception is thrown

Throws:

java.lang.UnsupportedOperationException - is always thrown as it makes no sense to attach a traverser to a graph

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