org.apache.tinkerpop.gremlin.process.remote.traversal

Class AbstractRemoteTraversal<S,E>

java.lang.Object

org.apache.tinkerpop.gremlin.process.remote.traversal.AbstractRemoteTraversal<S,E>

All Implemented Interfaces:

Serializable, AutoCloseable, Cloneable, Iterator<E>, RemoteTraversal<S,E>, Traversal<S,E>, Traversal.Admin<S,E>

Direct Known Subclasses:

DriverRemoteTraversal, EmbeddedRemoteTraversal

public abstract class AbstractRemoteTraversal<S,E>
extends Object
implements RemoteTraversal<S,E>

This is a stub implementation for RemoteTraversal and requires that the nextTraverser() method is implemented from Traversal.Admin. It is this method that gets called from RemoteStep when the Traversal is iterated.

Author:

Stephen Mallette (http://stephen.genoprime.com)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal

Traversal.Admin<S,E>, Traversal.Exceptions, Traversal.Symbols

Constructor Summary

Constructors

Constructor and Description
AbstractRemoteTraversal()

Method Summary

Modifier and Type	Method and Description
<S2,E2> Traversal.Admin<S2,E2>	addStep(int index, Step<?,?> step) Add a Step to an arbitrary point in the traversal.
void	applyStrategies() Apply the registered TraversalStrategies to the traversal.
Traversal.Admin<S,E>	clone() Cloning is used to duplicate the traversal typically in OLAP environments.
Bytecode	getBytecode() Get the Bytecode associated with the construction of this traversal.
Optional<Graph>	getGraph() Gets the Graph instance associated directly to this Traversal or through its parent.
TraversalParent	getParent() Get the TraversalParent Step that is the parent of this traversal.
TraversalSideEffects	getSideEffects() Get the TraversalSideEffects associated with the traversal.
List<Step>	getSteps() Get the Step instances associated with this traversal.
TraversalStrategies	getStrategies() Get the TraversalStrategies associated with this traversal.
TraverserGenerator	getTraverserGenerator() Get the TraverserGenerator associated with this traversal.
Set<TraverserRequirement>	getTraverserRequirements() Get the set of all TraverserRequirements for this traversal.
boolean	isLocked() When the traversal has had its TraversalStrategies applied to it, it is locked.
void	lock() Lock the traversal and perform any final adjustments to it after strategy application.
abstract Traverser.Admin<E>	nextTraverser() Note that internally #nextTraverser() is called from within a loop (specifically in AbstractStep.next() that breaks properly when a NoSuchElementException is thrown.
<S2,E2> Traversal.Admin<S2,E2>	removeStep(int index) Remove a Step from the traversal.
void	setGraph(Graph graph)
void	setParent(TraversalParent step) Set the TraversalParent Step that is the parent of this traversal.
void	setSideEffects(TraversalSideEffects sideEffects) Set the TraversalSideEffects of this traversal.
void	setStrategies(TraversalStrategies strategies) Set the TraversalStrategies to be used by this traversal at evaluation time.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal.Admin

addStart, addStarts, addStep, equals, getEndStep, getStartStep, getTraversalSource, getTraverserSetSupplier, isRoot, removeStep, reset

Methods inherited from interface org.apache.tinkerpop.gremlin.process.traversal.Traversal

asAdmin, close, explain, fill, forEachRemaining, forEachRemaining, iterate, next, none, notifyClose, profile, promise, toBulkSet, toList, toSet, toStream, tryNext

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Constructor Detail

AbstractRemoteTraversal

public AbstractRemoteTraversal()

Method Detail

nextTraverser

public abstract Traverser.Admin<E> nextTraverser()

Note that internally #nextTraverser() is called from within a loop (specifically in AbstractStep.next() that breaks properly when a NoSuchElementException is thrown. In other words the "results" should be iterated to force that failure.

Specified by:

nextTraverser in interface Traversal.Admin<S,E>

getSideEffects

public TraversalSideEffects getSideEffects()

Description copied from interface: Traversal.Admin

Get the TraversalSideEffects associated with the traversal. This method should not be called externally for purposes of retrieving side-effects as traversal results. Traversal results should only be returned by way of the execution of the traversal itself. Should a side-effect of a traversal be needed it should only be obtained by using GraphTraversal.cap(String, String...) so that the side-effect can be included as part of the traversal iteration. Relying on this method to get side-effects in these situations may not result in consistent behavior across all types of executions and environments (e.g. remoting).

Specified by:

getSideEffects in interface Traversal.Admin<S,E>

Returns:

The traversal sideEffects

getBytecode

public Bytecode getBytecode()

Description copied from interface: Traversal.Admin

Get the Bytecode associated with the construction of this traversal.

Specified by:

getBytecode in interface Traversal.Admin<S,E>

Returns:

the byte code representation of the traversal

getSteps

public List<Step> getSteps()

Description copied from interface: Traversal.Admin

Get the Step instances associated with this traversal. The steps are ordered according to their linked list structure as defined by Step.getPreviousStep() and Step.getNextStep().

Specified by:

getSteps in interface Traversal.Admin<S,E>

Returns:

the ordered steps of the traversal

addStep

public <S2,E2> Traversal.Admin<S2,E2> addStep(int index,
                                              Step<?,?> step)
                                       throws IllegalStateException

Description copied from interface: Traversal.Admin

Add a Step to an arbitrary point in the traversal.

Specified by:

addStep in interface Traversal.Admin<S,E>

Type Parameters:

S2 - the new start type of the traversal (if the added step was a start step)

E2 - the new end type of the traversal (if the added step was an end step)

Parameters:

index - the location in the traversal to insert the step

step - the step to add

Returns:

the newly modulated traversal

Throws:

IllegalStateException - if the TraversalStrategies have already been applied

removeStep

public <S2,E2> Traversal.Admin<S2,E2> removeStep(int index)
                                          throws IllegalStateException

Description copied from interface: Traversal.Admin

Remove a Step from the traversal.

Specified by:

removeStep in interface Traversal.Admin<S,E>

Type Parameters:

S2 - the new start type of the traversal (if the removed step was a start step)

E2 - the new end type of the traversal (if the removed step was an end step)

Parameters:

index - the location in the traversal of the step to be evicted

Returns:

the newly modulated traversal

Throws:

IllegalStateException - if the TraversalStrategies have already been applied

applyStrategies

public void applyStrategies()
                     throws IllegalStateException

Description copied from interface: Traversal.Admin

Apply the registered TraversalStrategies to the traversal. Once the strategies are applied, the traversal is "locked" and can no longer have steps added to it. The order of operations for strategy applications should be: globally id steps, apply each strategy in turn to root traversal, then recursively to nested traversals.

Specified by:

applyStrategies in interface Traversal.Admin<S,E>

Throws:

IllegalStateException - if the TraversalStrategies have already been applied

getTraverserGenerator

public TraverserGenerator getTraverserGenerator()

Description copied from interface: Traversal.Admin

Get the TraverserGenerator associated with this traversal. The traversal generator creates Traverser instances that are respective of the traversal's TraverserRequirement.

Specified by:

getTraverserGenerator in interface Traversal.Admin<S,E>

Returns:

the generator of traversers

getTraverserRequirements

public Set<TraverserRequirement> getTraverserRequirements()

Description copied from interface: Traversal.Admin

Get the set of all TraverserRequirements for this traversal.

Specified by:

getTraverserRequirements in interface Traversal.Admin<S,E>

Returns:

the features of a traverser that are required to execute properly in this traversal

setSideEffects

public void setSideEffects(TraversalSideEffects sideEffects)

Description copied from interface: Traversal.Admin

Set the TraversalSideEffects of this traversal.

Specified by:

setSideEffects in interface Traversal.Admin<S,E>

Parameters:

sideEffects - the sideEffects to set for this traversal.

setStrategies

public void setStrategies(TraversalStrategies strategies)

Description copied from interface: Traversal.Admin

Set the TraversalStrategies to be used by this traversal at evaluation time.

Specified by:

setStrategies in interface Traversal.Admin<S,E>

Parameters:

strategies - the strategies to use on this traversal

getStrategies

public TraversalStrategies getStrategies()

Description copied from interface: Traversal.Admin

Get the TraversalStrategies associated with this traversal.

Specified by:

getStrategies in interface Traversal.Admin<S,E>

Returns:

the strategies associated with this traversal

setParent

public void setParent(TraversalParent step)

Description copied from interface: Traversal.Admin

Set the TraversalParent Step that is the parent of this traversal. Traversals can be nested and this is the means by which the traversal tree is connected. If there is no parent, then it should be a EmptyStep.

Specified by:

setParent in interface Traversal.Admin<S,E>

Parameters:

step - the traversal holder parent step or EmptyStep if it has no parent

getParent

public TraversalParent getParent()

Description copied from interface: Traversal.Admin

Get the TraversalParent Step that is the parent of this traversal. Traversals can be nested and this is the means by which the traversal tree is walked.

Specified by:

getParent in interface Traversal.Admin<S,E>

Returns:

the traversal holder parent step or EmptyStep if it has no parent.

clone

public Traversal.Admin<S,E> clone()

Description copied from interface: Traversal.Admin

Cloning is used to duplicate the traversal typically in OLAP environments.

Specified by:

clone in interface Traversal.Admin<S,E>

Overrides:

clone in class Object

Returns:

The cloned traversal

isLocked

public boolean isLocked()

Description copied from interface: Traversal.Admin

When the traversal has had its TraversalStrategies applied to it, it is locked.

Specified by:

isLocked in interface Traversal.Admin<S,E>

Returns:

whether the traversal is locked

lock

public void lock()

Description copied from interface: Traversal.Admin

Lock the traversal and perform any final adjustments to it after strategy application.

Specified by:

lock in interface Traversal.Admin<S,E>

getGraph

public Optional<Graph> getGraph()

Description copied from interface: Traversal.Admin

Gets the Graph instance associated directly to this Traversal or through its parent.

Specified by:

getGraph in interface Traversal.Admin<S,E>

setGraph

public void setGraph(Graph graph)

Specified by:

setGraph in interface Traversal.Admin<S,E>