de.lmu.ifi.dbs.elki.persistent
Class AbstractStoringPageFile<P extends Page>

java.lang.Object
  de.lmu.ifi.dbs.elki.persistent.AbstractPageFile<P>
      de.lmu.ifi.dbs.elki.persistent.AbstractStoringPageFile<P>

Type Parameters:

P - Page type

All Implemented Interfaces:

PageFile<P>, PageFileStatistics

Direct Known Subclasses:

MemoryPageFile, OnDiskArrayPageFile, PersistentPageFile

public abstract class AbstractStoringPageFile<P extends Page>
extends AbstractPageFile<P>

Abstract class implementing general methods of a PageFile. A PageFile stores objects that implement the Page interface.

Field Summary

protected Stack<Integer>	emptyPages A stack holding the empty page ids.
protected int	nextPageID The last page ID.
protected int	pageSize The size of a page in Bytes.

Fields inherited from class de.lmu.ifi.dbs.elki.persistent.AbstractPageFile

readAccess, writeAccess

Constructor Summary

protected

AbstractStoringPageFile(int pageSize) Creates a new PageFile.

Method Summary

void	deletePage(int pageID) Deletes the node with the specified id from this file.
PageFileStatistics	getInnerStatistics() Get statistics for the inner page file, if present.
private Integer	getNextEmptyPageID() Returns the next empty page id.
int	getNextPageID() Returns the next page id.
int	getPageSize() Get the page size of this page file.
boolean	initialize(PageHeader header) Initialize the page file with the given header - return "true" if the file already existed.
void	setNextPageID(int nextPageID) Sets the next page id.
Integer	setPageID(P page) Sets the id of the given page.

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

close, getReadOperations, getWriteOperations, resetPageAccess, writePage, writePage

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.lmu.ifi.dbs.elki.persistent.PageFile

clear, readPage

Field Detail

emptyPages

protected Stack<Integer> emptyPages

A stack holding the empty page ids.

nextPageID

protected int nextPageID

The last page ID.

pageSize

protected int pageSize

The size of a page in Bytes.

Constructor Detail

AbstractStoringPageFile

protected AbstractStoringPageFile(int pageSize)

Creates a new PageFile.

Method Detail

setPageID

public Integer setPageID(P page)

Sets the id of the given page.

Parameters:

page - the page to set the id

Returns:

the page id

deletePage

public void deletePage(int pageID)

Deletes the node with the specified id from this file.

Parameters:

pageID - the id of the node to be deleted

getNextEmptyPageID

private Integer getNextEmptyPageID()

Returns the next empty page id.

Returns:

the next empty page id

getNextPageID

public int getNextPageID()

Returns the next page id.

Returns:

the next page id

setNextPageID

public void setNextPageID(int nextPageID)

Sets the next page id.

Parameters:

nextPageID - the next page id to be set

getPageSize

public int getPageSize()

Get the page size of this page file.

Returns:

page size

initialize

public boolean initialize(PageHeader header)

Initialize the page file with the given header - return "true" if the file already existed.

Parameters:

header - Header

Returns:

true when the file already existed.

getInnerStatistics

public PageFileStatistics getInnerStatistics()

Description copied from interface: PageFileStatistics

Get statistics for the inner page file, if present.

Returns:

Inner page file statistics, or null.