org.deegree.io.rtree
Class PersistentPageFile

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

All Implemented Interfaces:

Serializable

 class PersistentPageFile
extends PageFile

A persistent implementation of a PageFile implemented based on a RandomAccesFile.

Structure of the File


-- Header --
int pageFileVersion
int dimension
int capacity = maxLoad + 1 for Overflow
int minimum


-- Body --
a sequence of page one after another with:
int typ - 1 LeafNode 2 NoneLeafNode
int place - index of entry of this node in father node
int counter - current used space in the node
int parentNode - page number of father node
int pageNumber - own page number
- for(i = 0; i < capacity; i++)
int data Entry i - page number of childnode or object ID of data entry
- always dependend on dimension = x
double pMin x.Dimension - pMin of the common HyperBoundingBox
double pMax x.Dimension - pMax of the common HyperBoundingBox
- for(i = 0; i < capacity; i++)
double pMin x.Dimension - pMin HyperBoundingBox for Entry i
double pMax x.Dimension - pMax HyperBoundingBox for Entry i


int entspr. 4 Bytes - double entspr. 8 Bytes


PageSize = (4 * (5 + capacity)) + (capacity + 1) * (dimension * 16)

Author:

Wolfgang Baer - WBaer@gmx.de

Field Summary

Fields inherited from class org.deegree.io.rtree.PageFile

capacity, dimension, minimum

Constructor Summary

protected

PersistentPageFile(String fileName) Constructor

Method Summary

protected void	close() Closes the pagefile.
protected Node	deleteNode(int pageNumber) Marks the node at given page number as deleted.
protected void	finalize()
protected void	initialize(int dimension, int capacity) Initializes the PersistentPageFile.
protected Node	readNode(int pageFileNumber) Reads a node from the PageFile for given index
protected 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 org.deegree.io.rtree.PageFile

getCapacity, getDimension, getMinimum

Methods inherited from class java.lang.Object

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

Constructor Detail

PersistentPageFile

protected PersistentPageFile(String fileName)

Constructor

Parameters:

fileName -

Method Detail

initialize

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

Initializes the PersistentPageFile. Overrides initialize in PageFile.

Overrides:

initialize in class PageFile

Parameters:

dimension - - dimension of the data

capacity - - capacity of a node

Throws:

PageFileException

readNode

protected Node readNode(int pageFileNumber)
                 throws PageFileException

Description copied from class: PageFile

Reads a node from the PageFile for given index

Specified by:

readNode in class PageFile

Parameters:

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

Returns:

Node

Throws:

PageFileException

See Also:

PageFile.readNode(int)

writeNode

protected int writeNode(Node node)
                 throws PageFileException

Description copied from class: PageFile

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

Specified by:

writeNode in class PageFile

Parameters:

node - - Node to write

Returns:

int - page number

Throws:

PageFileException

See Also:

PageFile.writeNode(Node)

deleteNode

protected Node deleteNode(int pageNumber)
                   throws PageFileException

Description copied from class: PageFile

Marks the node at given page number as deleted.

Specified by:

deleteNode in class PageFile

Parameters:

pageNumber - - page number

Returns:

Node - deleted node

Throws:

PageFileException

See Also:

PageFile.deleteNode(int)

close

protected void close()
              throws PageFileException

Description copied from class: PageFile

Closes the pagefile.

Specified by:

close in class PageFile

Throws:

PageFileException

See Also:

PageFile.close()

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable