com.datastax.driver.dse.graph.Path Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of dse-java-driver-core Show documentation

A driver for DataStax Enterprise (DSE) and Apache Cassandra 1.2+ clusters that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol, supporting DSE-specific features such as geospatial types, DSE Graph and DSE authentication.

There is a newer version: 2.4.0

Show newest version

/*
 * Copyright DataStax, Inc.
 *
 * This software can be used solely with DataStax Enterprise. Please consult the license at
 * http://www.datastax.com/terms/datastax-dse-driver-license-terms
 */
package com.datastax.driver.dse.graph;

import java.util.List;
import java.util.Set;

/**
 * A walk through a graph as defined by a traversal.
 *
 * Clients typically obtain instances of this class by calling {@link GraphNode#asPath()}, for
 * example:
 *
 * 
 *     GraphNode n = dseSession.executeGraph("g.V().hasLabel('some_vertex').outE().inV().path()").one();
 *     Path path = n.asPath();
 * 
 */
public interface Path extends Iterable {

  /**
   * Returns the sets of labels of the steps traversed by this path, or an empty list, if this path
   * is empty.
   *
   * The returned list is immutable.
   *
   * @return the sets of labels of the steps traversed by this path.
   */
  List> getLabels();

  /**
   * Returns the objects traversed by this path, or an empty list, if this path is empty.
   *
   * 
The returned list is immutable.
   *
   * @return the objects traversed by this path.
   */
  List getObjects();

  /**
   * Returns the size of this path, that is, the number of steps this path traversed.
   *
   * @return the size of this path.
   */
  int size();

  /**
   * Returns the object associated with the given step of this path.
   *
   * 
The step index is zero-based, i.e. the first step has index {@code 0}.
   *
   * 
If the index is out of bounds, this method returns {@code null}; no exception will be
   * thrown.
   *
   * @param index the zero-based step index to find the object for.
   * @return the object associated with the given step index.
   */
  GraphNode getObject(int index);

  /**
   * Returns the first object with the given label in this path.
   *
   * 
If the label is associated with more then one step, then this method returns the object at
   * the first step with that label.
   *
   * 
If the label does not exist in this path, this method returns {@code null}.
   *
   * @param label the label to find an object for.
   * @return the first object with the given label.
   */
  GraphNode getObject(String label);

  /**
   * Returns the objects with the given label in this path.
   *
   * 
If the label is unique, the returned list will contain only one element.
   *
   * 
If the label is associated with more then one step, then the list will contain as many
   * elements as the number of times the label appears in this path's steps, in order.
   *
   * 
If the label does not exist in this path, an empty list is returned.
   *
   * The returned list is immutable.
   *
   * @param label the label to find objects for.
   * @return the objects with the given label.
   */
  List getObjects(String label);

  /**
   * Returns whether this path has at least one step with the given label.
   *
   * @param label the label to search.
   * @return {@code true} if this path has at least one step with the given label, {@code false}
   *     otherwise.
   */
  boolean hasLabel(String label);
}