org.netbeans.mdr.persistence.btreeimpl.btreestorage
Class BtreeFileSource

java.lang.Object
  org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeFileSource

All Implemented Interfaces:

BtreePageSource, MofidGenerator, FileCache.NotifyOnCommit

public class BtreeFileSource
extends java.lang.Object
implements BtreePageSource, FileCache.NotifyOnCommit

BtreePageSource implementation for pages which are stored directly in a file (the primary index pages) rather than as repository objects. The file access is all handled by the FileCache class.

Version:

1.0

Author:

Dana Bergen

Constructor Summary

BtreeFileSource(int fileId, FileCache fileCache, int pageSize, boolean isNew, MofidGenerator mGen, BtreeStorage storage)
Constructor for a BtreeFileSource from a new or existing index file.

Method Summary

void	dirtyPage(BtreePage page) Notifies the btree that the caller is going to modify this page.
java.lang.String	getMofidPrefix() Get the prefix for this repository
long	getNextMofid() get the next unique ID for this repository
BtreePage	getPage(byte[] pageId, Btree btree) Get a BtreePage by its pageId.
EntryTypeInfo	getPageIdInfo() Get an EntryTypeInfo for the datatype of this BtreePageSource's page IDs.
int	getPageIdLength() Returns the length of a page ID.
int	getPageSize() Returns the size of a page.
BtreePage	getRootPage(Btree btree) Return the root page if it already exists, otherwise create it.
BtreeStorage	getStorage()
boolean	isNoPage(byte[] pageId) Test whether the passed-in pageId contains the special value noPageId
BigKeyPage	newBigKeyPage(Btree btree) Returns a newly allocated BigKeyPage.
BtreePage	newPage(Btree btree) Returns a newly allocated btree page.
void	prepareToCommit() Prepares all cached modified pages to be written out.
void	setNoPage(byte[] pageId) Set the passed-in pageId to contain the special value noPageId
void	unpinPage(BigKeyPage page) Notify the BtreePageSource that the caller is done using this page.
void	unpinPage(BtreePage page) Notifies the btree that the caller is done using this page.

Methods inherited from class java.lang.Object

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

Constructor Detail

BtreeFileSource

public BtreeFileSource(int fileId,
                       FileCache fileCache,
                       int pageSize,
                       boolean isNew,
                       MofidGenerator mGen,
                       BtreeStorage storage)
                throws StorageException

Constructor for a BtreeFileSource from a new or existing index file.

Parameters:

fileId - file ID to use in FileCache requests

fileCache - source of index pages

pageSize - size of index pages

isNew - true if this index is being newly created

mGen - Mofid generator

Throws:

StorageException

Method Detail

getPageIdInfo

public EntryTypeInfo getPageIdInfo()

Description copied from interface: BtreePageSource

Get an EntryTypeInfo for the datatype of this BtreePageSource's page IDs.

Specified by:

getPageIdInfo in interface BtreePageSource

setNoPage

public void setNoPage(byte[] pageId)

Set the passed-in pageId to contain the special value noPageId

Specified by:

setNoPage in interface BtreePageSource

Parameters:

pageId - byte array to be filled in

isNoPage

public boolean isNoPage(byte[] pageId)

Test whether the passed-in pageId contains the special value noPageId

Specified by:

isNoPage in interface BtreePageSource

Returns:

true if the pageId is the null page ID, otherwise false

prepareToCommit

public void prepareToCommit()
                     throws StorageException

Prepares all cached modified pages to be written out.

Specified by:

prepareToCommit in interface FileCache.NotifyOnCommit

Throws:

StorageException

getRootPage

public BtreePage getRootPage(Btree btree)
                      throws StorageException

Return the root page if it already exists, otherwise create it.

Specified by:

getRootPage in interface BtreePageSource

Parameters:

btree - Btree

Returns:

BtreePage which is the root page

Throws:

StorageException

getPage

public BtreePage getPage(byte[] pageId,
                         Btree btree)
                  throws StorageException

Get a BtreePage by its pageId.

Specified by:

getPage in interface BtreePageSource

Parameters:

pageId - Byte array containing pageId

btree - btree to which the page belongs

Returns:

The page identified by pageId.

Throws:

StorageException - If the page is not valid

newPage

public BtreePage newPage(Btree btree)
                  throws StorageException

Returns a newly allocated btree page.

Specified by:

newPage in interface BtreePageSource

Parameters:

btree - btree to which the page belongs

Returns:

A new BtreePage

Throws:

StorageException - If the page is not valid

newBigKeyPage

public BigKeyPage newBigKeyPage(Btree btree)
                         throws StorageException

Returns a newly allocated BigKeyPage. BigKeyPages are not recycled. They are only cached while in use.

Specified by:

newBigKeyPage in interface BtreePageSource

Parameters:

btree - btree to which the page belongs

Returns:

the BigKeyPage

Throws:

StorageException

unpinPage

public void unpinPage(BtreePage page)

Notifies the btree that the caller is done using this page. This decrements its pinned count in the btree cache. It does not change its pinned status in the FileCache; that only happens when a page is removed from the btree cache.

Specified by:

unpinPage in interface BtreePageSource

Parameters:

page - BtreePage to be unpinned

unpinPage

public void unpinPage(BigKeyPage page)
               throws StorageException

Description copied from interface: BtreePageSource

Notify the BtreePageSource that the caller is done using this page.

Specified by:

unpinPage in interface BtreePageSource

Parameters:

page - BigKeyPage

Throws:

StorageException

dirtyPage

public void dirtyPage(BtreePage page)
               throws StorageException

Notifies the btree that the caller is going to modify this page. This must be called prior to modifying the page contents.

Specified by:

dirtyPage in interface BtreePageSource

Parameters:

page - The page being modified

Throws:

StorageException

getPageIdLength

public int getPageIdLength()

Description copied from interface: BtreePageSource

Returns the length of a page ID.

Specified by:

getPageIdLength in interface BtreePageSource

Returns:

length of a page ID from this BtreePageSource

getPageSize

public int getPageSize()

Description copied from interface: BtreePageSource

Returns the size of a page.

Specified by:

getPageSize in interface BtreePageSource

Returns:

size of a page from this BtreePageSource

getNextMofid

public long getNextMofid()

Description copied from interface: MofidGenerator

get the next unique ID for this repository

Specified by:

getNextMofid in interface MofidGenerator

getMofidPrefix

public java.lang.String getMofidPrefix()

Description copied from interface: MofidGenerator

Get the prefix for this repository

Specified by:

getMofidPrefix in interface MofidGenerator

getStorage

public BtreeStorage getStorage()

Specified by:

getStorage in interface BtreePageSource