package de.lmu.ifi.dbs.elki.index.tree;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2012
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 .
*/
import java.util.Enumeration;
import de.lmu.ifi.dbs.elki.persistent.Page;
/**
* This interface defines the common requirements of nodes in an index
* structure. A node has to extend the page interface for persistent storage and
* has to provide an enumeration over its children.
*
* @author Elke Achtert
*
* @apiviz.composedOf Entry
*
* @param the type of Entry used in the index
*/
public interface Node extends Page {
/**
* Returns an enumeration of the children paths of this node.
*
* @param parentPath the path to this node
* @return an enumeration of the children paths of this node
*/
Enumeration> children(IndexTreePath parentPath);
/**
* Returns the number of entries of this node.
*
* @return the number of entries of this node
*/
int getNumEntries();
/**
* Returns true if this node is a leaf node, false otherwise.
*
* @return true if this node is a leaf node, false otherwise
*/
boolean isLeaf();
/**
* Returns the entry at the specified index.
*
* @param index the index of the entry to be returned
* @return the entry at the specified index
*/
E getEntry(int index);
/**
* Adds a new leaf entry to this node's children and returns the index of the
* entry in this node's children array. An UnsupportedOperationException will
* be thrown if the entry is not a leaf entry or this node is not a leaf node.
*
* @param entry the leaf entry to be added
* @return the index of the entry in this node's children array
* @throws UnsupportedOperationException if entry is not a leaf entry or this
* node is not a leaf node
*/
int addLeafEntry(E entry);
/**
* Adds a new directory entry to this node's children and returns the index of
* the entry in this node's children array. An UnsupportedOperationException
* will be thrown if the entry is not a directory entry or this node is not a
* directory node.
*
* @param entry the directory entry to be added
* @return the index of the entry in this node's children array
* @throws UnsupportedOperationException if entry is not a directory entry or
* this node is not a directory node
*/
int addDirectoryEntry(E entry);
}