/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Aug 1, 2012
*/
package com.bigdata.btree;
import com.bigdata.htree.HTree;
/**
* Extended interface for tree-structured indices.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
public interface ISimpleTreeIndexAccess extends ISimpleIndexAccess {
/**
* The #of non-leaf nodes in the tree.
*/
long getNodeCount();
/**
* The #of leaf nodes in the tree.
*/
long getLeafCount();
/**
* The #of tuples in the tree.
*/
long getEntryCount();
/**
* Return <code>true</code> iff the tree is balanced.
* <p>
* Note: Not all tree-structured indices are balanced. For example, the
* {@link BTree} is balanced, but the {@link HTree} is not balanced. The
* height of an unbalanced tree must be discovered through a traversal of
* the tree.
*/
boolean isBalanced();
/**
* The height of the tree. The height is the #of levels minus one. A tree
* with only a root leaf has <code>height := 0</code>. A tree with a root
* node and one level of leaves under it has <code>height := 1</code>.
* <p>
* Note that all leaves of a balanced tree (such as a B+Tree) are at the
* same height (this is what is means to be "balanced"). Also note that the
* height only changes when we split or join the root node (a B+Tree
* maintains balance by growing and shrinking in levels from the top rather
* than the leaves).
*
* @throws UnsupportedOperationException
* if the tree is not a balanced tree.
*
* @see #isBalanced()
*/
int getHeight();
}