package org.neo4j.graphdb.traversal;
/**
* Represents the type of uniqueness to expect from a traversal, for example the
* uniqueness of nodes or relationships to visit during a traversal.
*/
public enum Uniqueness
{
/**
* A node cannot be traversed more than once. This is what the legacy
* traversal framework does.
*/
NODE_GLOBAL,
/**
* For each returned node there's a unique path from the start node to it.
*/
NODE_PATH,
/**
* This is like {@link Uniqueness#NODE_GLOBAL}, but only guarantees
* uniqueness among the most recent visited nodes, with a configurable
* count. Traversing a huge graph is quite memory intensive in that it keeps
* track of <i>all</i> the nodes it has visited. For huge graphs a traverser
* can hog all the memory in the JVM, causing {@link OutOfMemoryError}.
* Together with this {@link Uniqueness} you can supply a count, which is
* the number of most recent visited nodes. This can cause a node to be
* visited more than once, but scales infinitely.
*/
NODE_RECENT,
/**
* A relationship cannot be traversed more than once, whereas nodes can.
*/
RELATIONSHIP_GLOBAL,
/**
* For each returned node there's a (relationship wise) unique path from the
* start node to it.
*/
RELATIONSHIP_PATH,
/**
* Same as for {@link Uniqueness#NODE_RECENT}, but for relationships.
*/
RELATIONSHIP_RECENT,
/**
* No restriction (the user will have to manage it).
*/
NONE;
}