diskmgr
Class DiskMgr

java.lang.Object
  diskmgr.DiskMgr

All Implemented Interfaces:

GlobalConst

public class DiskMgr
extends java.lang.Object
implements GlobalConst

Field Summary

Fields inherited from interface global.GlobalConst

EMPTY_SLOT, FIRST_PAGEID, INVALID_PAGEID, MAX_COLSIZE, MAX_TUPSIZE, NAME_MAXLEN, PAGE_SIZE, PIN_DISKIO, PIN_MEMCPY, UNPIN_CLEAN, UNPIN_DIRTY

Constructor Summary

DiskMgr()
default constructor.

Method Summary

void	add_file_entry(java.lang.String fname, PageId start_page_num) Adds a file entry to the header page(s).
PageId	allocate_page(int run_size) Allocates a set of pages on disk, given the run size.
void	allocate_page(PageId start_page_num) Allocate a set of pages where the run size is taken to be 1 by default.
void	allocate_page(PageId start_page_num, int runsize) user specified run_size
void	closeDB() Close DB file.
java.lang.String	db_name() Functions to return some characteristics of the database.
int	db_num_pages()
int	db_page_size()
void	DBDestroy() Destroy the database, removing the file that stores it.
void	deallocate_page(PageId start_page_num) Deallocate a set of pages starting at the specified page number with run size = 1
void	deallocate_page(PageId start_page_num, int run_size) Deallocate a set of pages starting at the specified page number and a run size can be specified.
void	delete_file_entry(java.lang.String fname) Delete the entry corresponding to a file from the header page(s).
void	dump_space_map() Print out the space map of the database.
PageId	get_file_entry(java.lang.String name) Get the entry corresponding to the given file.
void	openDB(java.lang.String fname) Open the database with the given name.
void	openDB(java.lang.String fname, int num_pgs) DB Constructors.
void	read_page(PageId pageno, Page apage) Read the contents of the specified page into a Page object
void	write_page(PageId pageno, Page apage) Write the contents in a page object to the specified page.

Methods inherited from class java.lang.Object

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

Constructor Detail

DiskMgr

public DiskMgr()

default constructor.

Method Detail

openDB

public void openDB(java.lang.String fname)
            throws java.io.IOException,
                   InvalidPageNumberException,
                   FileIOException,
                   DiskMgrException

Open the database with the given name.

Parameters:

fname - DB_name

Throws:

java.io.IOException - I/O errors

FileIOException - file I/O error

InvalidPageNumberException - invalid page number

DiskMgrException - error caused by other layers

openDB

public void openDB(java.lang.String fname,
                   int num_pgs)
            throws java.io.IOException,
                   chainexception.ChainException

DB Constructors. Create a database with the specified number of pages where the page size is the default page size.

Parameters:

fname - DB name

num_pgs - number of pages in DB

Throws:

java.io.IOException - I/O errors

chainexception.ChainException

closeDB

public void closeDB()
             throws java.io.IOException

Close DB file.

Throws:

java.io.IOException - I/O errors.

DBDestroy

public void DBDestroy()
               throws java.io.IOException

Destroy the database, removing the file that stores it.

Throws:

java.io.IOException - I/O errors.

read_page

public void read_page(PageId pageno,
                      Page apage)
               throws InvalidPageNumberException,
                      FileIOException,
                      java.io.IOException

Read the contents of the specified page into a Page object

Parameters:

pageno - pageId which will be read

apage - page object which holds the contents of page

Throws:

InvalidPageNumberException - invalid page number

FileIOException - file I/O error

java.io.IOException - I/O errors

write_page

public void write_page(PageId pageno,
                       Page apage)
                throws InvalidPageNumberException,
                       FileIOException,
                       java.io.IOException

Write the contents in a page object to the specified page.

Parameters:

pageno - pageId will be wrote to disk

apage - the page object will be wrote to disk

Throws:

InvalidPageNumberException - invalid page number

FileIOException - file I/O error

java.io.IOException - I/O errors

allocate_page

public PageId allocate_page(int run_size)
                     throws chainexception.ChainException,
                            java.io.IOException

Allocates a set of pages on disk, given the run size.

Returns:

The new page's id

Throws:

java.io.IOException

chainexception.ChainException

java.lang.IllegalArgumentException - if run_size is invalid

java.lang.IllegalStateException - if the database is full

allocate_page

public void allocate_page(PageId start_page_num)
                   throws chainexception.ChainException,
                          java.io.IOException

Allocate a set of pages where the run size is taken to be 1 by default. Gives back the page number of the first page of the allocated run. with default run_size =1

Parameters:

start_page_num - page number to start with

Throws:

OutOfSpaceException - database is full

InvalidRunSizeException - invalid run size

InvalidPageNumberException - invalid page number

FileIOException - DB file I/O errors

java.io.IOException - I/O errors

DiskMgrException - error caused by other layers

chainexception.ChainException

allocate_page

public void allocate_page(PageId start_page_num,
                          int runsize)
                   throws java.io.IOException,
                          chainexception.ChainException

user specified run_size

Parameters:

start_page_num - the starting page id of the run of pages

runsize - the number of page need allocated

Throws:

java.io.IOException - I/O errors

chainexception.ChainException

deallocate_page

public void deallocate_page(PageId start_page_num,
                            int run_size)
                     throws java.io.IOException,
                            chainexception.ChainException

Deallocate a set of pages starting at the specified page number and a run size can be specified.

Parameters:

start_page_num - the start pageId to be deallocate

run_size - the number of pages to be deallocated

Throws:

java.io.IOException - I/O errors

chainexception.ChainException

deallocate_page

public void deallocate_page(PageId start_page_num)
                     throws chainexception.ChainException

Deallocate a set of pages starting at the specified page number with run size = 1

Parameters:

start_page_num - the start pageId to be deallocate

Throws:

InvalidRunSizeException - invalid run size

InvalidPageNumberException - invalid page number

FileIOException - file I/O error

java.io.IOException - I/O errors

DiskMgrException - error caused by other layers

chainexception.ChainException

add_file_entry

public void add_file_entry(java.lang.String fname,
                           PageId start_page_num)
                    throws FileNameTooLongException,
                           InvalidPageNumberException,
                           InvalidRunSizeException,
                           DuplicateEntryException,
                           OutOfSpaceException,
                           FileIOException,
                           java.io.IOException,
                           DiskMgrException

Adds a file entry to the header page(s).

Parameters:

fname - file entry name

start_page_num - the start page number of the file entry

Throws:

FileNameTooLongException - invalid file name (too long)

InvalidPageNumberException - invalid page number

InvalidRunSizeException - invalid DB run size

DuplicateEntryException - entry for DB is not unique

OutOfSpaceException - database is full

FileIOException - file I/O error

java.io.IOException - I/O errors

DiskMgrException - error caused by other layers

delete_file_entry

public void delete_file_entry(java.lang.String fname)
                       throws FileEntryNotFoundException,
                              java.io.IOException,
                              FileIOException,
                              InvalidPageNumberException,
                              DiskMgrException

Delete the entry corresponding to a file from the header page(s).

Parameters:

fname - file entry name

Throws:

FileEntryNotFoundException - file does not exist

FileIOException - file I/O error

java.io.IOException - I/O errors

InvalidPageNumberException - invalid page number

DiskMgrException - error caused by other layers

get_file_entry

public PageId get_file_entry(java.lang.String name)
                      throws java.io.IOException,
                             FileIOException,
                             InvalidPageNumberException,
                             DiskMgrException

Get the entry corresponding to the given file.

Parameters:

name - file entry name

Throws:

java.io.IOException - I/O errors

FileIOException - file I/O error

InvalidPageNumberException - invalid page number

DiskMgrException - error caused by other layers

db_name

public java.lang.String db_name()

Functions to return some characteristics of the database.

db_num_pages

public int db_num_pages()

db_page_size

public int db_page_size()

dump_space_map

public void dump_space_map()
                    throws DiskMgrException,
                           java.io.IOException,
                           FileIOException,
                           InvalidPageNumberException

Print out the space map of the database. The space map is a bitmap showing which pages of the db are currently allocated.

Throws:

FileIOException - file I/O error

java.io.IOException - I/O errors

InvalidPageNumberException - invalid page number

DiskMgrException - error caused by other layers