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

Class DataFileImp

java.lang.Object

com.semedy.reasoner.edb.persistentstore.bplustree.DataFileImp

All Implemented Interfaces:

DataFile, Closeable, AutoCloseable

Direct Known Subclasses:

BlockedDataFile

public class DataFileImp
extends Object
implements Closeable, DataFile

Manages file space for data like indice values, symbols etc.
File space is usable with variable lengths.
A free space list is managed. Data are compressed with lz4

Author:

angele

Constructor Summary

Constructors

Constructor	Description
DataFileImp(String filePath, boolean compress)

Method Summary

Modifier and Type	Method	Description
boolean	checkSanity()	checks free space list
boolean	checkSanity1()	checks for double occurences
void	clear()	clear file
void	close()	Close file
void	create()	Create a file.
void	delete()	delete file
Iterator<DataFileElement>	elements()	iterator for the file elements
void	flush()	Flush file
void	free(long offset)	Frees up space at offset
int	length(long pos)	length of file piece at pos
boolean	open()	Open an existing file.
byte[]	read(long offset)	Reads data at offset from file and returns it
int	readInt(long position)	read integer at position
void	transactionBegin()	begin transaction
void	transactionCommit()	commit transaction
void	transactionRollback()	rollback transaction
long	write(byte[] data)	write data into file.
long	writeCompressed(byte[] data, int originalLength)	write compressed to file.
long	writeDirect(byte[] data)
long	writeDirect(long offset, int originallength, byte[] data)

Methods inherited from class java.lang.Object

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

Constructor Details

DataFileImp

public DataFileImp(String filePath,
 boolean compress)

Method Details

transactionBegin

public void transactionBegin()
                      throws IOException

Description copied from interface: DataFile

begin transaction

Specified by:

transactionBegin in interface DataFile

Throws:

IOException

transactionCommit

public void transactionCommit()
                       throws IOException

Description copied from interface: DataFile

commit transaction

Specified by:

transactionCommit in interface DataFile

Throws:

IOException

transactionRollback

public void transactionRollback()
                         throws IOException

Description copied from interface: DataFile

rollback transaction

Specified by:

transactionRollback in interface DataFile

Throws:

IOException

create

public void create()
            throws IOException,
EDBException

Create a file. If it exists it will be cleared. File has a header of 32 bytes

Specified by:

create in interface DataFile

Throws:

IOException

EDBException

open

public boolean open()
             throws IOException

Open an existing file. Return true if successful.

Specified by:

open in interface DataFile

Returns:

Throws:

IOException

checkSanity1

public boolean checkSanity1()

checks for double occurences

Specified by:

checkSanity1 in interface DataFile

Returns:

checkSanity

public boolean checkSanity()

checks free space list

Specified by:

checkSanity in interface DataFile

Returns:

writeDirect

public long writeDirect(byte[] data)
                 throws IOException

Throws:

IOException

writeDirect

public long writeDirect(long offset,
 int originallength,
 byte[] data)
                 throws IOException

Throws:

IOException

read

public byte[] read(long offset)
            throws IOException

Reads data at offset from file and returns it

Specified by:

read in interface DataFile

Parameters:

offset -

Returns:

Throws:

IOException

free

public void free(long offset)
          throws IOException

Frees up space at offset

Specified by:

free in interface DataFile

Parameters:

offset -

Throws:

IOException

close

public void close()
           throws IOException

Close file

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface DataFile

Throws:

IOException

flush

public void flush()
           throws IOException

Flush file

Specified by:

flush in interface DataFile

Throws:

IOException

readInt

public int readInt(long position)
            throws IOException

Description copied from interface: DataFile

read integer at position

Specified by:

readInt in interface DataFile

Returns:

Throws:

IOException

write

public long write(byte[] data)
           throws IOException

write data into file. Returns address of data

Specified by:

write in interface DataFile

Parameters:

data -

Returns:

Throws:

IOException

writeCompressed

public long writeCompressed(byte[] data,
 int originalLength)
                     throws IOException

write compressed to file. Returns address of data

Specified by:

writeCompressed in interface DataFile

Parameters:

data -

originalLength -

Returns:

Throws:

IOException

delete

public void delete()

delete file

Specified by:

delete in interface DataFile

length

public int length(long pos)
           throws IOException

length of file piece at pos

Specified by:

length in interface DataFile

Parameters:

pos -

Returns:

Throws:

IOException

clear

public void clear()
           throws IOException,
EDBException

clear file

Specified by:

clear in interface DataFile

Throws:

IOException

EDBException

elements

public Iterator<DataFileElement> elements()

iterator for the file elements

Specified by:

elements in interface DataFile

Returns: