package de.lmu.ifi.dbs.elki.result.optics;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures

Copyright (C) 2011
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import de.lmu.ifi.dbs.elki.database.ids.DBID;
import de.lmu.ifi.dbs.elki.distance.distancevalue.Distance;

/**
 * Generic Cluster Order Entry Interface.
 * 
 * @author Erich Schubert
 * 
 * @apiviz.landmark
 * 
 * @apiviz.composedOf DBID
 * @apiviz.composedOf Distance
 *
 * @param <D> Distance type
 */
public interface ClusterOrderEntry<D extends Distance<D>> {
  /**
   * Returns the object id of this entry.
   * 
   * @return the object id of this entry
   */
  public DBID getID();

  /**
   * Returns the id of the predecessor of this entry if this entry has a
   * predecessor, null otherwise.
   * 
   * @return the id of the predecessor of this entry
   */
  public DBID getPredecessorID();

  /**
   * Returns the reachability distance of this entry
   * 
   * @return the reachability distance of this entry
   */
  public D getReachability();
}