File Class Reference

#include <file.h>

Inheritance diagram for File:

Collaboration diagram for File:

Public Member Functions
	File (Catalog *catalog, BufferManager *buf_mgr)
	Constructor. Initializes common state associated with every file, including catalog, buf_mgr, and schema.
virtual	~File ()
	Destructor. Data members are cleaned up, but none of the dynamically allocated data members are deleted. The underlying Unix file is not deleted.
virtual void	createHeader ()=0
	Allocates and initializes the header. Is a virtual method to be overridden at each derived class.
virtual void	flushHeader ()=0
	Flushes Header Page to disk. Is a virtual method to be overridden at each derived class.
FileId	getFileId ()
	Returns the FileId of the File.
virtual void	printFile ()
	Prints out information and/or the contents of the file. Can be overwritten in derived classes. Useful for debugging and testing purposes.
PageId	getHeaderId ()
	Returns Header PageId.

Protected Member Functions
void	_setFileId (FileId file_id)
	Sets the file_id and the schema fields of this File.

Protected Attributes
FileId	file_id
Catalog *	catalog
BufferManager *	buf_mgr
PageId	header_id

Friends
class	Catalog
class	FileManager

Detailed Description

SwatDB File Class. The base class for all file-type objects in the system. A File is used to represent a relation or index in the system. This base class inludes state and methods that are common to every type of file in the system.

Constructor & Destructor Documentation

File()

File::File	(	Catalog *	catalog,
		BufferManager *	buf_mgr
	)

Constructor. Initializes common state associated with every file, including catalog, buf_mgr, and schema.

Parameters

catalog	Pointer to the SwatDB Catalog. Needed for getting file and idex relation files and schema.
buf_mgr	Pointer to the SwatDB Buffer Manager. Needed for de/allocating Pages, for getting and flushing Pages.

Precondition

Input paramaters (pointers) are all valid.

Postcondition

The data members of File are initialized. file_id and header_id, however, are not set.

Member Function Documentation

_setFileId()

void File::_setFileId ( FileId  file_id )

protected

Sets the file_id and the schema fields of this File.

NOTE: this is called by

1. Catalog.createFile so that a File object can be added to the Catalog as part of an entry before the Catalog has determined its fileId (our solution to a chicken and egg problem).
2. FileManager._loadFile via its constructor when initializing SwatDB from saved db state, we add entries to the Catalog without Files, and the File manager creates File * for them and updates each file's fid field after creation (could just have another constructor to handle this case)

Precondition

The given FileId is valid.

Postcondition

file_id is set to the given value.

Parameters

file_id

The File's FileId.

createHeader()

virtual void File::createHeader ( )

pure virtual

Allocates and initializes the header. Is a virtual method to be overridden at each derived class.

Implemented in HashIndexFile, and HeapFile.

flushHeader()

virtual void File::flushHeader ( )

pure virtual

Flushes Header Page to disk. Is a virtual method to be overridden at each derived class.

Implemented in HashIndexFile, and HeapFile.

getFileId()

FileId File::getFileId

(

)

Returns the FileId of the File.

Returns

The FileId of the File.

getHeaderId()

PageId File::getHeaderId

(

)

Returns Header PageId.

Precondition

None.

Postcondition

Header PageId of the File is returned.

Returns

The Header PageId.

Member Data Documentation

buf_mgr

BufferManager* File::buf_mgr

protected

Pointer to the SwatDB BufferManager

catalog

Catalog* File::catalog

protected

Pointer to the SwatDB Catalog

file_id

FileId File::file_id

protected

The File's FileId.

header_id

PageId File::header_id

protected

PageId for the header Page of the File.

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

• file.h