Package com.semedy.reasoner.edb.persistentstore.bplustree

Class BPlusTreeFile<KeyType,KeyBufferType>

java.lang.Object

com.semedy.reasoner.edb.persistentstore.bplustree.BPlusTreeFile<KeyType,KeyBufferType>

Type Parameters:

KeyType -

KeyBufferType -

public class BPlusTreeFile<KeyType,KeyBufferType>
extends Object

This file handles the writing of nodes to files and the reading of nodes back.

Author:

angele

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_FILE_NAME

Constructor Summary

Constructors

Constructor	Description
BPlusTreeFile(String filename, int m, int keyLengthInBytes, int nodeLengthInBytes, KeysFactory<KeyType,KeyBufferType> keysFactory, LeafFactory<KeyType,KeyBufferType> leafFactory, BPlusTree<KeyType,KeyBufferType> bplustree, int additionalHeadSpace, boolean compress)	General constructor.

Method Summary

Modifier and Type	Method	Description
boolean	checkSanity(String message)	checks sanity
void	close()	Close file
void	create()	create file
void	flush()	flush file
byte[]	getHeader()	return file header
BPlusNode<KeyType,KeyBufferType>	getNode(byte[] bytes, int offset)	get node out of bytes and offset
long	getSizeOnDisc()	get size of file
boolean	open()	open file
int	readFlags()	write flags
long[]	readGrounds(long[] grounds)	read grounds
BPlusNode<KeyType,KeyBufferType>	readNode(int offset, boolean shadow)	public method for reading a node at a given file offset.
long	readNumberOfElements()	read number of elements
int	readRootOffset()	read offset of root
void	releaseNode(BPlusNode<KeyType,KeyBufferType> node, boolean shadow)	free up disk space for bplus node
void	transactionBegin()	begin transaction
void	transactionCommit()	commit
void	transactionRollback()	rollback transaction
void	writeAdditionalHeadSpace(int additional)	write additional headspace (used for grounds)
void	writeFlags(int flags)	read flags
void	writeGrounds(long[] grounds)	write grounds
int	writeInternalNode(BPlusInternalNode<KeyType,KeyBufferType> toWrite, int offset)	write an internal node at offset
int	writeLeaf(BPlusLeaf<KeyType,KeyBufferType> toWrite, int offset)	write a leaf at offset
long	writeNewInternalNode(BPlusInternalNode<KeyType,KeyBufferType> toWrite)	Writes a new internal node to the end of the file.
int	writeNewLeaf(BPlusLeaf<KeyType,KeyBufferType> toWrite)	Writes a new leaf to the end of the file.
void	writeNodeSize(int size)	write node size
void	writeNumberOfElements(long numElements)	write number of elements
void	writeRootOffset(int offset)	write offset of root

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_FILE_NAME

public static final String DEFAULT_FILE_NAME

See Also:

• Constant Field Values

Constructor Details

BPlusTreeFile

public BPlusTreeFile(String filename,
 int m,
 int keyLengthInBytes,
 int nodeLengthInBytes,
 KeysFactory<KeyType,KeyBufferType> keysFactory,
 LeafFactory<KeyType,KeyBufferType> leafFactory,
 BPlusTree<KeyType,KeyBufferType> bplustree,
 int additionalHeadSpace,
 boolean compress)
              throws IOException,
EDBException

General constructor.

Parameters:

filename -

m -

keyLengthInBytes -

nodeLengthInBytes -

keysFactory -

leafFactory -

bplustree -

additionalHeadSpace -

Throws:

IOException

EDBException

Method Details

getSizeOnDisc

public long getSizeOnDisc()

get size of file

Returns:

open

public boolean open()
             throws EDBException,
IOException

open file

Returns:

Throws:

EDBException

IOException

create

public void create()
            throws IOException,
EDBException

create file

Throws:

IOException

EDBException

getHeader

public byte[] getHeader()

return file header

Returns:

checkSanity

public boolean checkSanity(String message)

checks sanity

Returns:

close

public void close()
           throws IOException

Close file

Throws:

IOException

flush

public void flush()
           throws IOException

flush file

Throws:

IOException

transactionCommit

public void transactionCommit()
                       throws IOException

commit

Throws:

IOException

transactionRollback

public void transactionRollback()
                         throws IOException

rollback transaction

Throws:

IOException

transactionBegin

public void transactionBegin()
                      throws IOException

begin transaction

Throws:

IOException

readNode

public BPlusNode<KeyType,KeyBufferType> readNode(int offset,
 boolean shadow)
                                          throws IOException

public method for reading a node at a given file offset.
First determines the type of node, then calls the appropriate helper method.

Parameters:

offset -

shadow - , read from shadow tree

Returns:

Throws:

IOException

getNode

public BPlusNode<KeyType,KeyBufferType> getNode(byte[] bytes,
 int offset)
                                         throws IOException

get node out of bytes and offset

Parameters:

bytes -

offset -

Returns:

Throws:

IOException

writeNewInternalNode

public long writeNewInternalNode(BPlusInternalNode<KeyType,KeyBufferType> toWrite)
                          throws IOException,
EDBException

Writes a new internal node to the end of the file.

Parameters:

toWrite -

Returns:

location (file offset) of the leaf

Throws:

IOException

EDBException

writeNewLeaf

public int writeNewLeaf(BPlusLeaf<KeyType,KeyBufferType> toWrite)
                 throws IOException,
EDBException

Writes a new leaf to the end of the file.

Parameters:

toWrite -

Returns:

location (file offset) of the leaf

Throws:

IOException

EDBException

writeInternalNode

public int writeInternalNode(BPlusInternalNode<KeyType,KeyBufferType> toWrite,
 int offset)
                      throws IOException,
EDBException

write an internal node at offset

Parameters:

toWrite -

offset -

Returns:

Throws:

IOException

EDBException

writeLeaf

public int writeLeaf(BPlusLeaf<KeyType,KeyBufferType> toWrite,
 int offset)
              throws IOException,
EDBException

write a leaf at offset

Parameters:

toWrite -

offset -

Returns:

Throws:

IOException

EDBException

releaseNode

public void releaseNode(BPlusNode<KeyType,KeyBufferType> node,
 boolean shadow)
                 throws IOException

free up disk space for bplus node

Parameters:

node -

Throws:

IOException

writeNumberOfElements

public void writeNumberOfElements(long numElements)

write number of elements

Parameters:

numElements -

readNumberOfElements

public long readNumberOfElements()

read number of elements

Returns:

readFlags

public int readFlags()
              throws IOException

write flags

Returns:

Throws:

IOException

writeFlags

public void writeFlags(int flags)
                throws IOException

read flags

Parameters:

flags -

Throws:

IOException

writeNodeSize

public void writeNodeSize(int size)

write node size

Parameters:

size -

writeRootOffset

public void writeRootOffset(int offset)

write offset of root

Parameters:

offset -

readRootOffset

public int readRootOffset()

read offset of root

Returns:

writeAdditionalHeadSpace

public void writeAdditionalHeadSpace(int additional)
                              throws IOException

write additional headspace (used for grounds)

Parameters:

additional -

Throws:

IOException

writeGrounds

public void writeGrounds(long[] grounds)
                  throws IOException

write grounds

Parameters:

grounds -

Throws:

IOException

readGrounds

public long[] readGrounds(long[] grounds)
                   throws IOException

read grounds

Parameters:

grounds -

Returns:

Throws:

IOException