Class to provide read/write cache services to a 1-Wire memory device. More...

Public Member Functions
	MemoryCache (OneWireContainer device)
	Construct a new memory cache for provided 1-wire container device.
	MemoryCache (OneWireContainer[] devices)
	Construct a new memory cache for provided 1-wire container device.
int	getNumberPages ()
	Gets the number of pages in this cache.
int	getNumberPagesInBank (int bankNum)
	Gets the number of pages in the specified bank number.
int	getPageOffsetForDevice (int deviceNum)
	Gets the page number of the first page on the specified device.
int	getMaxPacketDataLength ()
	Gets the maximum number of bytes for data in each page.
boolean	isWriteOnce ()
	Check if this memory device is write-once.
int	readPagePacket (int page, byte[] readBuf, int offset) throws OneWireIOException, OneWireException
	Read a page packet.
void	writePagePacket (int page, byte[] writeBuf, int offset, int buflen) throws OneWireIOException, OneWireException
	Write a page packet into the cache.
void	sync () throws OneWireIOException, OneWireException
	Flush the pages written back to the 1-Wire device.
void	addOwner (Object tobj)
	Add an owner to this memory cache.
void	removeOwner (Object tobj)
	Remove the specified owner of this memory cache.
boolean	noOwners ()
	Check to see if there on no owners of this memory cache.
void	removeWriteOpen (String filePath)
	Remove the provided filePath from the list of files currently opened to write.
boolean	isOpenedToWrite (String filePath, boolean addToList)
	Check to see if the provided filePath is currently opened to write.
boolean	handlePageBitmap ()
	Check to see if this memory cache should handle the page bitmap.
void	markPageUsed (int page)
	Mark the specified page as used in the page bitmap.
boolean	freePage (int page)
	free the specified page as being un-used in the page bitmap
int	getFirstFreePage ()
	Get the first free page from the page bitmap.
int	getNextFreePage ()
	Get the next free page from the page bitmap.
int	getNumberFreePages () throws OneWireException
	Get the total number of free pages in this Filesystem.
int	getBitMapPageNumber ()
	Gets the page number used in the remote page bitmap in an OTP device.
int	getBitMapNumberOfPages ()
	Get the number of pages used for the remote page bitmap in an OTP device.
PagedMemoryBank	getMemoryBankForPage (int page)
	Get's the memory bank object for the specified page.
int	getLocalPage (int page)
	Get's the local page number on the memory bank object for the specified page.
void	clearLastPageRead ()
	Clears the lastPageRead global so that a readPage will not try to continue where the last page left off.

Detailed Description

Class to provide read/write cache services to a 1-Wire memory device.

Writes are only performed when this classes sync() method is called. Provides page bitmap services for OTP devices.

Objectives:

Cache read/written pages
write only on sync()
write order is oldest to newest.
Collect redirection information when appropriate

Author:: DS

Version:: 0.01, 1 June 2001

See also:: com.dalsemi.onewire.application.file.OWFile; com.dalsemi.onewire.application.file.OWFileDescriptor; com.dalsemi.onewire.application.file.OWFileInputStream; com.dalsemi.onewire.application.file.OWFileOutputStream

Constructor & Destructor Documentation

MemoryCache ( OneWireContainer device )

Construct a new memory cache for provided 1-wire container device.

Parameters:

device 1-Wire container

MemoryCache ( OneWireContainer[] devices )

Construct a new memory cache for provided 1-wire container device.

Parameters:

device 1-Wire container

Member Function Documentation

void addOwner ( Object tobj )

Add an owner to this memory cache.

This will be tracked for later cleanup.

Parameters:

tobj	owner of instance

void clearLastPageRead ( )

Clears the lastPageRead global so that a readPage will not try to continue where the last page left off.

This should be called anytime exclusive access to the 1-Wire canot be guaranteed.

boolean freePage ( int page )

free the specified page as being un-used in the page bitmap

Parameters:

page	number to mark as un-used

Returns:: true if the page as be been marked as un-used, false if the page is on an OTP device and cannot be freed

int getBitMapNumberOfPages ( )

Get the number of pages used for the remote page bitmap in an OTP device.

Returns:: number of pages used in page bitmap

int getBitMapPageNumber ( )

Gets the page number used in the remote page bitmap in an OTP device.

Returns:: page number used in the directory for the remote page bitmap

int getFirstFreePage ( )

Get the first free page from the page bitmap.

Returns:: first page number that is free to write

int getLocalPage ( int page )

Get's the local page number on the memory bank object for the specified page.

This is significant if the Filesystem spans memory banks on the same or different devices.

int getMaxPacketDataLength ( )

Gets the maximum number of bytes for data in each page.

Returns:: max number of data bytes per page

PagedMemoryBank getMemoryBankForPage ( int page )

Get's the memory bank object for the specified page.

This is significant if the Filesystem spans memory banks on the same or different devices.

int getNextFreePage ( )

Get the next free page from the page bitmap.

Returns:: next page number that is free to write

int getNumberFreePages ( ) throws OneWireException

Get the total number of free pages in this Filesystem.

Returns:: number of pages free

Exceptions:

OneWireException when an IO exception occurs

int getNumberPages ( )

Gets the number of pages in this cache.

Returns:: number of pages in the cache

int getNumberPagesInBank ( int bankNum )

Gets the number of pages in the specified bank number.

Parameters:

bankNum bank number to retrieve number of pages

Returns:: number of pages in the bank

int getPageOffsetForDevice ( int deviceNum )

Gets the page number of the first page on the specified device.

If the device number is not valid then return 0.

Parameters:

deviceNum device number to retrieve page offset

Returns:: page number of first page on device

boolean handlePageBitmap ( )

Check to see if this memory cache should handle the page bitmap.

Returns:: true if this memory cache should handle the page bitmap

boolean isOpenedToWrite	(	String	filePath,
		boolean	addToList
	)

Check to see if the provided filePath is currently opened to write.

Optionally add it to the list if it not already there.

Parameters:

filePath	file to check to see if opened to write
addToList	true to add file to list if not present

Returns:: true if file was not in the opened to write list

boolean isWriteOnce ( )

Check if this memory device is write-once.

If this is true then the page bitmap facilities in this class will be used.

Returns:: true if this device is write-once

void markPageUsed ( int page )

Mark the specified page as used in the page bitmap.

Parameters:

page	number to mark as used

boolean noOwners ( )

Check to see if there on no owners of this memory cache.

Returns:: true if not owners of this memory cache

int readPagePacket	(	int	page,
		byte[]	readBuf,
		int	offset
	)		throws OneWireIOException, OneWireException

Read a page packet.

If the page is available in the cache then return that data.

Parameters:

page	page to read
readBuf	buffer to place the data in
offset	offset into the read buffer

Returns:: the number byte in the packet

Exceptions:

OneWireException	when the adapter is not setup properly
OneWireIOException	when an 1-Wire IO error occures

void removeOwner ( Object tobj )

Remove the specified owner of this memory cache.

Parameters:

tobj	owner of instance

void removeWriteOpen ( String filePath )

Remove the provided filePath from the list of files currently opened to write.

Parameters:

filePath file to remove from write list

void sync ( ) throws OneWireIOException, OneWireException

Flush the pages written back to the 1-Wire device.

Exceptions:

OneWireException	when the adapter is not setup properly
OneWireIOException	when an 1-Wire IO error occures

void writePagePacket	(	int	page,
		byte[]	writeBuf,
		int	offset,
		int	buflen
	)		throws OneWireIOException, OneWireException

Write a page packet into the cache.

Parameters:

page	page to write
writeBuf	buffer container the data to write
offset	offset into write buffer
buflen	length of data to write

The documentation for this class was generated from the following file:

MemoryCache.java

MemoryCache Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation