de.lmu.ifi.dbs.elki.index.tree
Class TreeIndexHeader

java.lang.Object
  de.lmu.ifi.dbs.elki.persistent.DefaultPageHeader
      de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader

All Implemented Interfaces:

PageHeader

Direct Known Subclasses:

MkTreeHeader, RdKNNTreeHeader

public class TreeIndexHeader
extends DefaultPageHeader

Encapsulates the header information of a tree like index structure. This information is needed for persistent storage.

Author:

Elke Achtert

Field Summary

(package private) int	dirCapacity The capacity of a directory node (= 1 + maximum number of entries in a directory node).
(package private) int	dirMinimum The minimum number of entries in a directory node.
(package private) int	leafCapacity The capacity of a leaf node (= 1 + maximum number of entries in a leaf node).
(package private) int	leafMinimum The minimum number of entries in a leaf node.
private static int	SIZE The size of this header in Bytes, which is 16 Bytes ( 4 Bytes for dirCapacity, leafCapacity, dirMinimum, and leafMinimum).

Constructor Summary

TreeIndexHeader()
Empty constructor for serialization.

TreeIndexHeader(int pageSize, int dirCapacity, int leafCapacity, int dirMinimum, int leafMinimum)
Creates a new header with the specified parameters.

Method Summary

int	getDirCapacity() Returns the capacity of a directory node (= 1 + maximum number of entries in a directory node).
int	getDirMinimum() Returns the minimum number of entries in a directory node.
int	getLeafCapacity() Returns the capacity of a leaf node (= 1 + maximum number of entries in a leaf node).
int	getLeafMinimum() Returns the minimum number of entries in a leaf node.
void	readHeader(RandomAccessFile file) Initializes this header from the specified file.
int	size() Returns DefaultPageHeader.size() plus the value of SIZE).
void	writeHeader(RandomAccessFile file) Writes this header to the specified file.

Methods inherited from class de.lmu.ifi.dbs.elki.persistent.DefaultPageHeader

asByteArray, getPageSize, readHeader

Methods inherited from class java.lang.Object

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

Field Detail

SIZE

private static int SIZE

The size of this header in Bytes, which is 16 Bytes ( 4 Bytes for dirCapacity, leafCapacity, dirMinimum, and leafMinimum).

dirCapacity

int dirCapacity

The capacity of a directory node (= 1 + maximum number of entries in a directory node).

leafCapacity

int leafCapacity

The capacity of a leaf node (= 1 + maximum number of entries in a leaf node).

dirMinimum

int dirMinimum

The minimum number of entries in a directory node.

leafMinimum

int leafMinimum

The minimum number of entries in a leaf node.

Constructor Detail

TreeIndexHeader

public TreeIndexHeader()

Empty constructor for serialization.

TreeIndexHeader

public TreeIndexHeader(int pageSize,
                       int dirCapacity,
                       int leafCapacity,
                       int dirMinimum,
                       int leafMinimum)

Creates a new header with the specified parameters.

Parameters:

pageSize - the size of a page in bytes

dirCapacity - the maximum number of entries in a directory node

leafCapacity - the maximum number of entries in a leaf node

dirMinimum - the minimum number of entries in a directory node

leafMinimum - the minimum number of entries in a leaf node

Method Detail

readHeader

public void readHeader(RandomAccessFile file)
                throws IOException

Initializes this header from the specified file. Calls DefaultPageHeader#readHeader(file) and reads the integer values of dirCapacity, leafCapacity, dirMinimum, and leafMinimum from the file.

Specified by:

readHeader in interface PageHeader

Overrides:

readHeader in class DefaultPageHeader

Parameters:

file - the file to which this header belongs

Throws:

IOException - if an I/O-error occurs during reading

writeHeader

public void writeHeader(RandomAccessFile file)
                 throws IOException

Writes this header to the specified file. Writes the integer values of dirCapacity, leafCapacity, dirMinimum, and leafMinimum to the file.

Specified by:

writeHeader in interface PageHeader

Overrides:

writeHeader in class DefaultPageHeader

Parameters:

file - the file to which this header belongs

Throws:

IOException - IOException if an I/O-error occurs during writing

getDirCapacity

public int getDirCapacity()

Returns the capacity of a directory node (= 1 + maximum number of entries in a directory node).

Returns:

the capacity of a directory node (= 1 + maximum number of entries in a directory node)

getLeafCapacity

public int getLeafCapacity()

Returns the capacity of a leaf node (= 1 + maximum number of entries in a leaf node).

Returns:

the capacity of a leaf node (= 1 + maximum number of entries in a leaf node)

getDirMinimum

public int getDirMinimum()

Returns the minimum number of entries in a directory node.

Returns:

the minimum number of entries in a directory node

getLeafMinimum

public int getLeafMinimum()

Returns the minimum number of entries in a leaf node.

Returns:

the minimum number of entries in a leaf node

size

public int size()

Returns DefaultPageHeader.size() plus the value of SIZE).

Specified by:

size in interface PageHeader

Overrides:

size in class DefaultPageHeader

Returns:

the size of this header in Bytes