org.deegree.io.rtree
Class PageFile

java.lang.Object
  org.deegree.io.rtree.PageFile

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

MemoryPageFile, PersistentPageFile

abstract class PageFile
extends java.lang.Object
implements java.io.Serializable

Abstract class implementing general methods of a PageFile.

Version:

$Revision: 12519 $, $Date: 2008-06-25 11:37:30 +0200 (Mi, 25 Jun 2008) $

Author:

Wolfgang Baer - WBaer@gmx.de, last edited by: $Author: aschmitz $

Field Summary

protected int	capacity capacity of a node (= MaxLoad + 1)
protected int	dimension dimension of saved data
protected int	minimum minimum load of a node

Constructor Summary

PageFile()

Method Summary

protected abstract void	close() Closes the pagefile.
protected abstract Node	deleteNode(int pageFileNumber) Marks the node at given page number as deleted.
protected int	getCapacity() Returns the capacity of a node in the PageFile.
protected int	getDimension() Returns the dimension of the PageFile
protected int	getMinimum() Returns the minimum load of a node
protected void	initialize(int dimension, int capacity) Initializes the PageFile.
protected abstract Node	readNode(int pageFileNumber) Reads a node from the PageFile for given index
protected abstract int	writeNode(Node node) Writes a node into the PageFile Method tests if node has already a PageNumber, otherwise a new page number is assigned and returned.

Methods inherited from class java.lang.Object

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

Field Detail

dimension

protected int dimension

dimension of saved data

capacity

protected int capacity

capacity of a node (= MaxLoad + 1)

minimum

protected int minimum

minimum load of a node

Constructor Detail

PageFile

PageFile()

Method Detail

getDimension

protected int getDimension()

Returns the dimension of the PageFile

Returns:

int

getMinimum

protected int getMinimum()

Returns the minimum load of a node

Returns:

int

getCapacity

protected int getCapacity()

Returns the capacity of a node in the PageFile. Capacity is defined a maximum load of a node plus 1 for overflow

Returns:

int

readNode

protected abstract Node readNode(int pageFileNumber)
                          throws PageFileException

Reads a node from the PageFile for given index

Parameters:

pageFileNumber - - index of page file number where node is saved

Returns:

Node

Throws:

PageFileException

writeNode

protected abstract int writeNode(Node node)
                          throws PageFileException

Writes a node into the PageFile Method tests if node has already a PageNumber, otherwise a new page number is assigned and returned.

Parameters:

node - - Node to write

Returns:

int - page number

Throws:

PageFileException

deleteNode

protected abstract Node deleteNode(int pageFileNumber)
                            throws PageFileException

Marks the node at given page number as deleted.

Parameters:

pageFileNumber - - page number

Returns:

Node - deleted node

Throws:

PageFileException

initialize

protected void initialize(int dimension,
                          int capacity)
                   throws PageFileException

Initializes the PageFile.

Parameters:

dimension - - dimension of the data

capacity - - capacity of a node

Throws:

PageFileException

close

protected abstract void close()
                       throws PageFileException

Closes the pagefile.

Throws:

PageFileException