org.exist.storage.btree
Class Paged

java.lang.Object
  org.exist.storage.btree.Paged

Direct Known Subclasses:

BTree

public abstract class Paged

extends java.lang.Object

Paged is a paged file foundation that is used by the BTree class and its subclasses.

Nested Class Summary

class	Paged.FileHeader FileHeader
class	Paged.Page Page
static class	Paged.PageHeader

Field Summary

protected static byte	DELETED
protected static Logger	LOG
protected static byte	OVERFLOW
protected static int	PAGE_SIZE
protected static byte	UNUSED

Constructor Summary

Paged()

Paged(java.io.File file)

Method Summary

void	backupToStream(java.io.OutputStream os) Backup the entire contents of the underlying file to an output stream.
boolean	close() Close the underlying files.
void	closeAndRemove() Completely close down the instance and all underlying resources and caches.
boolean	create()
abstract Paged.FileHeader	createFileHeader() createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.
abstract Paged.FileHeader	createFileHeader(boolean read) createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.
abstract Paged.FileHeader	createFileHeader(long pageCount) createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.
abstract Paged.FileHeader	createFileHeader(long pageCount, int pageSize) createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.
abstract Paged.PageHeader	createPageHeader() createPageHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a PageHeader.
boolean	exists()
boolean	flush()
java.io.File	getFile() getFile returns the file object for this Paged.
Paged.FileHeader	getFileHeader() getFileHeader returns the FileHeader
short	getFileVersion()
protected Paged.Page	getFreePage() getFreePage returns the first free Page from secondary storage.
protected Paged.Page	getPage(long pageNum) getPage returns the page specified by pageNum.
static int	getPageSize()
static java.lang.String	hexDump(byte[] data)
boolean	isOpened() Gets the opened attribute of the Paged object
boolean	isReadOnly()
boolean	open(short expectedVersion)
void	printFreeSpaceList() Debug
protected void	reuseDeleted(Paged.Page page)
protected void	setFile(java.io.File file) setFile sets the file object for this Paged.
static void	setPageSize(int pageSize)
protected void	unlinkPages(long pageNum) unlinkPages unlinks a set of pages starting at the specified page number.
protected void	unlinkPages(Paged.Page page) unlinkPages unlinks a set of pages starting at the specified Page.
protected void	writeValue(long page, Value value) writeValue writes the multi-Paged Value starting at the specified page number.
protected void	writeValue(Paged.Page page, byte[] data)
protected void	writeValue(Paged.Page page, Value value) writeValue writes the multi-Paged Value starting at the specified Page.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

protected static final Logger LOG

DELETED

protected static final byte DELETED

See Also:

Constant Field Values

OVERFLOW

protected static final byte OVERFLOW

See Also:

Constant Field Values

UNUSED

protected static final byte UNUSED

See Also:

Constant Field Values

PAGE_SIZE

protected static int PAGE_SIZE

Constructor Detail

Paged

public Paged()

Paged

public Paged(java.io.File file)
      throws DBException

Method Detail

getFileVersion

public short getFileVersion()

setPageSize

public static final void setPageSize(int pageSize)

getPageSize

public static final int getPageSize()

isReadOnly

public final boolean isReadOnly()

close

public boolean close()
              throws DBException

Close the underlying files.

Returns:

Throws:

DBException

create

public boolean create()
               throws DBException

Throws:

DBException

createFileHeader

public abstract Paged.FileHeader createFileHeader()

createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.

Returns:

a new FileHeader

createFileHeader

public abstract Paged.FileHeader createFileHeader(boolean read)
                                           throws java.io.IOException

createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.

Parameters:

read - If true, reads the FileHeader from disk

Returns:

a new FileHeader

Throws:

java.io.IOException - if an exception occurs

createFileHeader

public abstract Paged.FileHeader createFileHeader(long pageCount)

createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.

Parameters:

pageCount - The number of pages to allocate for primary storage

Returns:

a new FileHeader

createFileHeader

public abstract Paged.FileHeader createFileHeader(long pageCount,
                                                  int pageSize)

createFileHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a FileHeader.

Parameters:

pageCount - The number of pages to allocate for primary storage

pageSize - The size of a Page (should be a multiple of a FS block)

Returns:

a new FileHeader

createPageHeader

public abstract Paged.PageHeader createPageHeader()

createPageHeader must be implemented by a Paged implementation in order to create an appropriate subclass instance of a PageHeader.

Returns:

a new PageHeader

exists

public boolean exists()

flush

public boolean flush()
              throws DBException

Throws:

DBException

backupToStream

public void backupToStream(java.io.OutputStream os)
                    throws java.io.IOException

Backup the entire contents of the underlying file to an output stream.

Parameters:

os -

Throws:

java.io.IOException

getFile

public final java.io.File getFile()

getFile returns the file object for this Paged.

Returns:

The File

getFileHeader

public Paged.FileHeader getFileHeader()

getFileHeader returns the FileHeader

Returns:

The FileHeader

closeAndRemove

public void closeAndRemove()

Completely close down the instance and all underlying resources and caches.

getFreePage

protected final Paged.Page getFreePage()
                                throws java.io.IOException

getFreePage returns the first free Page from secondary storage. If no Pages are available, the file is grown as appropriate.

Returns:

The next free Page

Throws:

java.io.IOException - if an Exception occurs

getPage

protected final Paged.Page getPage(long pageNum)
                            throws java.io.IOException

getPage returns the page specified by pageNum.

Parameters:

pageNum - The Page number

Returns:

The requested Page

Throws:

java.io.IOException - if an Exception occurs

isOpened

public boolean isOpened()

Gets the opened attribute of the Paged object

Returns:

The opened value

open

public boolean open(short expectedVersion)
             throws DBException

Throws:

DBException

printFreeSpaceList

public void printFreeSpaceList()
                        throws java.io.IOException

Debug

Throws:

java.io.IOException - Description of the Exception

setFile

protected final void setFile(java.io.File file)
                      throws DBException

setFile sets the file object for this Paged.

Parameters:

file - The File

Throws:

DBException

unlinkPages

protected void unlinkPages(Paged.Page page)
                    throws java.io.IOException

unlinkPages unlinks a set of pages starting at the specified Page.

Parameters:

page - The starting Page to unlink

Throws:

java.io.IOException - if an Exception occurs

unlinkPages

protected final void unlinkPages(long pageNum)
                          throws java.io.IOException

unlinkPages unlinks a set of pages starting at the specified page number.

Parameters:

pageNum - Description of the Parameter

Throws:

java.io.IOException - if an Exception occurs

reuseDeleted

protected void reuseDeleted(Paged.Page page)
                     throws java.io.IOException

Throws:

java.io.IOException

writeValue

protected final void writeValue(Paged.Page page,
                                Value value)
                         throws java.io.IOException

writeValue writes the multi-Paged Value starting at the specified Page.

Parameters:

page - The starting Page

value - The Value to write

Throws:

java.io.IOException - if an Exception occurs

writeValue

protected final void writeValue(Paged.Page page,
                                byte[] data)
                         throws java.io.IOException

Throws:

java.io.IOException

writeValue

protected final void writeValue(long page,
                                Value value)
                         throws java.io.IOException

writeValue writes the multi-Paged Value starting at the specified page number.

Parameters:

page - The starting page number

value - The Value to write

Throws:

java.io.IOException - if an Exception occurs

hexDump

public static java.lang.String hexDump(byte[] data)