de.lmu.ifi.dbs.elki.persistent

Class AbstractPageFile<P extends Page>

java.lang.Object

de.lmu.ifi.dbs.elki.persistent.AbstractPageFile<P>

Type Parameters:

P - page type

All Implemented Interfaces:

PageFile<P>

Direct Known Subclasses:

AbstractStoringPageFile, LRUCache

public abstract class AbstractPageFile<P extends Page>
extends Object
implements PageFile<P>

Abstract base class for the page file API for both caches and true page files (in-memory and on-disk).

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
private Counter	readAccess The read I/O-Access of this file.
private Counter	writeAccess The write I/O-Access of this file.

Constructor Summary

Constructors

Constructor and Description
AbstractPageFile() Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes this file.
protected void	countRead() Count a page read access.
protected void	countWrite() Count a page write access.
protected abstract Logging	getLogger() Get the class logger.
void	logStatistics() Log some statistics to the appropriate logger.
protected abstract void	writePage(int pageid, P page) Perform the actual page write operation.
int	writePage(P page) Writes a page into this file.

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, deletePage, getNextPageID, getPageSize, initialize, readPage, setNextPageID, setPageID

Field Detail

readAccess

private Counter readAccess

The read I/O-Access of this file.

writeAccess

private Counter writeAccess

The write I/O-Access of this file.

Constructor Detail

AbstractPageFile

public AbstractPageFile()

Constructor.

Method Detail

getLogger

protected abstract Logging getLogger()

Get the class logger.

Returns:

Logger

writePage

public final int writePage(P page)

Writes a page into this file. The method tests if the page has already an id, otherwise a new id is assigned and returned.

Specified by:

writePage in interface PageFile<P extends Page>

Parameters:

page - the page to be written

Returns:

the id of the page

writePage

protected abstract void writePage(int pageid,
             P page)

Perform the actual page write operation.

Parameters:

pageid - Page id

page - Page to write

close

public void close()

Description copied from interface: PageFile

Closes this file.

Specified by:

close in interface PageFile<P extends Page>

logStatistics

public void logStatistics()

Description copied from interface: PageFile

Log some statistics to the appropriate logger.

Specified by:

logStatistics in interface PageFile<P extends Page>

countRead

protected void countRead()

Count a page read access.

countWrite

protected void countWrite()

Count a page write access.