com.bigdata.btree

Class BTreeStatistics

java.lang.Object

com.bigdata.btree.BTreeStatistics

All Implemented Interfaces:

IBTreeStatistics, Serializable

public class BTreeStatistics
extends Object
implements IBTreeStatistics, Serializable

A snapshot of the B+Tree statistics.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BTreeStatistics(AbstractBTree btree)

Method Summary

Methods

Modifier and Type	Method and Description
int	getBranchingFactor() The branching factor for the btree.
long	getEntryCount() The #of entries (aka tuples) in the AbstractBTree.
int	getHeight() The height of the btree.
long	getLeafCount() The #of leaf nodes in the AbstractBTree.
long	getNodeCount() The #of non-leaf nodes in the AbstractBTree.
IBTreeUtilizationReport	getUtilization() Computes and returns the utilization of the tree.
String	toString() Human readable representation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

BTreeStatistics

public BTreeStatistics(AbstractBTree btree)

Method Detail

getBranchingFactor

public int getBranchingFactor()

Description copied from interface: IBTreeStatistics

The branching factor for the btree.

Specified by:

getBranchingFactor in interface IBTreeStatistics

getHeight

public int getHeight()

Description copied from interface: IBTreeStatistics

The height of the btree. The height is the #of levels minus one. A btree with only a root leaf has height := 0. A btree with a root node and one level of leaves under it has height := 1. Note that all leaves of a btree are at the same height (this is what is means for the btree to be "balanced"). Also note that the height only changes when we split or join the root node (a btree maintains balance by growing and shrinking in levels from the top rather than the leaves).

Specified by:

getHeight in interface IBTreeStatistics

getNodeCount

public long getNodeCount()

Description copied from interface: IBTreeStatistics

The #of non-leaf nodes in the AbstractBTree. This is zero (0) for a new btree.

Specified by:

getNodeCount in interface IBTreeStatistics

getLeafCount

public long getLeafCount()

Description copied from interface: IBTreeStatistics

The #of leaf nodes in the AbstractBTree. This is one (1) for a new btree.

Specified by:

getLeafCount in interface IBTreeStatistics

getEntryCount

public long getEntryCount()

Description copied from interface: IBTreeStatistics

The #of entries (aka tuples) in the AbstractBTree. This is zero (0) for a new B+Tree. When the B+Tree supports delete markers, this value also includes tuples which have been marked as deleted.

Specified by:

getEntryCount in interface IBTreeStatistics

getUtilization

public IBTreeUtilizationReport getUtilization()

Description copied from interface: IBTreeStatistics

Computes and returns the utilization of the tree. The utilization figures do not factor in the space requirements of nodes and leaves.

Specified by:

getUtilization in interface IBTreeStatistics

toString

public String toString()

Human readable representation.

Overrides:

toString in class Object