wiscdb::PageFile Class Reference

Inheritance diagram for wiscdb::PageFile:

List of all members.

Public Member Functions
	PageFile (const std::string &name, const bool create_new)
	PageFile (const PageFile &other)
PageFile &	operator= (const PageFile &rhs)
	~PageFile ()
Page	allocatePage (PageId &new_page_number)
Page	readPage (const PageId page_number) const
void	writePage (const PageId page_number, const Page &new_page)
void	deletePage (const PageId page_number)
FileIterator	begin ()
FileIterator	end ()
Static Public Member Functions
static PageFile	create (const std::string &filename)
static PageFile	open (const std::string &filename)
Friends
class	FileIterator

---

Detailed Description

Definition at line 239 of file file.h.

---

Constructor & Destructor Documentation

wiscdb::PageFile::PageFile	(	const std::string &	name,
		const bool	create_new
	)

Constructs a file object representing a file on the filesystem.

Parameters:

name	Name of file.
create_new	Whether to create a new file.

Exceptions:

FileExistsException	If the underlying file exists and create_new is true.
FileNotFoundException	If the underlying file doesn't exist and create_new is false.

wiscdb::PageFile::PageFile

(

const PageFile &

other

)

Copy constructor.

Parameters:

other

File object to copy.

Returns:

A copy of the File object.

wiscdb::PageFile::~PageFile

(

)

Destructor that automatically closes the underlying file if no other File objects are using it.

---

Member Function Documentation

Page wiscdb::PageFile::allocatePage

(

PageId &

new_page_number

)

[virtual]

Allocates a new page in the file.

Returns:

The new page.

Implements wiscdb::File.

FileIterator wiscdb::PageFile::begin

(

)

Returns an iterator at the first page in the file.

Returns:

Iterator at first page of file.

static PageFile wiscdb::PageFile::create

(

const std::string &

filename

)

[static]

Creates a new file.

Parameters:

filename

Name of the file.

Exceptions:

FileExistsException

If the requested file already exists.

void wiscdb::PageFile::deletePage

(

const PageId

page_number

)

[virtual]

Deletes a page from the file.

Parameters:

page_number

Number of page to delete.

Implements wiscdb::File.

FileIterator wiscdb::PageFile::end

(

)

Returns an iterator representing the page after the last page in the file. This iterator should not be dereferenced.

Returns:

Iterator representing page after the last page in the file.

static PageFile wiscdb::PageFile::open

(

const std::string &

filename

)

[static]

Opens the file named fileName and returns the corresponding File object. It first checks if the file is already open. If so, then the new File object created uses the same input-output stream to read to or write fom that already open file. Reference count (open_counts_ static variable inside the File object) is incremented whenever an already open file is opened again. Otherwise the UNIX file is actually opened. The fileName and the stream associated with this File object are inserted into the open_streams_ map.

Parameters:

filename

Name of the file.

Exceptions:

FileNotFoundException

If the requested file doesn't exist.

PageFile& wiscdb::PageFile::operator=

(

const PageFile &

rhs

)

Assignment operator.

Parameters:

rhs	File object to assign.

Returns:

Newly assigned file object.

Page wiscdb::PageFile::readPage

(

const PageId

page_number

)

const [virtual]

Reads an existing page from the file.

Parameters:

page_number

Number of page to read.

Returns:

The page.

Exceptions:

InvalidPageException

If the page doesn't exist in the file or is not currently used.

Implements wiscdb::File.

void wiscdb::PageFile::writePage	(	const PageId	page_number,
		const Page &	new_page
	)		[virtual]

Writes a page into the file at the given page number. No bounds checking is performed.

Parameters:

page_number	Number of page whose contents to replace.
new_page	Page to write.

Implements wiscdb::File.

---

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

• file.h