org.neo4j.graphdb.traversal

Interface TraversalBranch

All Superinterfaces:

Iterable<PropertyContainer>, Path

public interface TraversalBranch
extends Path

Represents a position and a PathExpander with a traversal context, for example parent and an iterator of relationships to go next. It's a base to write a BranchSelector on top of.

Method Summary

Modifier and Type	Method and Description
boolean	continues()
void	evaluation(Evaluation eval) Can change evaluation outcome in a negative direction.
int	expanded() Returns the number of relationships this expansion source has expanded.
boolean	includes()
void	initialize(PathExpander expander, TraversalContext metadata) Initializes this TraversalBranch, the relationship iterator, Evaluation etc.
TraversalBranch	next(PathExpander expander, TraversalContext metadata) Returns the next expansion source from the expanded relationships from the current node.
TraversalBranch	parent() The parent expansion source which created this TraversalBranch.
void	prune() Explicitly tell this branch to be pruned so that consecutive calls to next(PathExpander, TraversalContext) is guaranteed to return null.
Object	state() Returns the state associated with this branch.

Methods inherited from interface org.neo4j.graphdb.Path

endNode, iterator, lastRelationship, length, nodes, relationships, reverseNodes, reverseRelationships, startNode, toString

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

parent

TraversalBranch parent()

The parent expansion source which created this TraversalBranch.

Returns:

the parent of this expansion source.

next

TraversalBranch next(PathExpander expander,
                     TraversalContext metadata)

Returns the next expansion source from the expanded relationships from the current node.

Parameters:

expander - an expander to decide which relationships to follow

metadata - the context of the traversal

Returns:

the next expansion source from this expansion source.

expanded

int expanded()

Returns the number of relationships this expansion source has expanded. In this count isn't included the relationship which led to coming here (since that could also be traversed, although skipped, when expanding this source).

Returns:

the number of relationships this expansion source has expanded.

prune

void prune()

Explicitly tell this branch to be pruned so that consecutive calls to next(PathExpander, TraversalContext) is guaranteed to return null.

continues

boolean continues()

Returns:

whether or not the traversal should continue further along this branch.

includes

boolean includes()

Returns:

whether or not this branch (the Path representation of this branch at least) should be included in the result of this traversal, i.e. returned as one of the Paths from f.ex. TraversalDescription.traverse(org.neo4j.graphdb.Node...)

evaluation

void evaluation(Evaluation eval)

Can change evaluation outcome in a negative direction. For example to force pruning.

Parameters:

eval - the Evaluation to AND with the current evaluation.

initialize

void initialize(PathExpander expander,
                TraversalContext metadata)

Initializes this TraversalBranch, the relationship iterator, Evaluation etc.

Parameters:

expander - PathExpander to use for getting relationships.

metadata - TraversalContext to update on progress.

state

Object state()

Returns the state associated with this branch. Why is this of type Object? The state object type only exists when specifying the expander in the TraversalDescription, not anywhere else. So in the internals of the traversal the state type is unknown and ignored.

Returns:

the state associated with this branch.