gr.uoa.di.madgik.searchlibrary.operatorlibrary.indexfuse
Class DiskBuffer

java.lang.Object
  gr.uoa.di.madgik.searchlibrary.operatorlibrary.indexfuse.DiskBuffer

public class DiskBuffer
extends Object

Class used to wrap a file buffer for the records that are beeing processed

Author:

UoA

Field Summary

long	rtime Time it took to read
long	wtime Time it took to write

Constructor Summary

DiskBuffer(String filename, boolean flag)
Creates a new DiskBuffer

Method Summary

void	clear() Clears the underlying structs
void	close() Closes the underlying file stream
FilePosition	persist(gr.uoa.di.madgik.grs.record.Record rec) Persists the provided record
gr.uoa.di.madgik.grs.record.Record	retrieve(FilePosition pos) Retrieves the record from the given position
Vector<gr.uoa.di.madgik.grs.record.Record>	retrieve(Vector<FilePosition> pos) Retrieves the records in teh given possitions

Methods inherited from class java.lang.Object

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

Field Detail

wtime

public long wtime

Time it took to write

rtime

public long rtime

Time it took to read

Constructor Detail

DiskBuffer

public DiskBuffer(String filename,
                  boolean flag)
           throws Exception

Creates a new DiskBuffer

Parameters:

filename - The name of the file to use

flag - iftrue The file is opened for writing, otherwise for reading

Throws:

Exception - An unrecoverable for the operation error occured

Method Detail

persist

public FilePosition persist(gr.uoa.di.madgik.grs.record.Record rec)
                     throws Exception

Persists the provided record

Parameters:

rec - The record to persist

Returns:

The position in the file buffer

Throws:

Exception - An unrecoverable for the operation error occured

close

public void close()
           throws Exception

Closes the underlying file stream

Throws:

Exception - An unrecoverable for the operation error occured

retrieve

public Vector<gr.uoa.di.madgik.grs.record.Record> retrieve(Vector<FilePosition> pos)
                                                    throws Exception

Retrieves the records in teh given possitions

Parameters:

pos - Teh possition to read from

Returns:

Teh records retrieved

Throws:

Exception - An unrecoverable for the operation error occured

retrieve

public gr.uoa.di.madgik.grs.record.Record retrieve(FilePosition pos)
                                            throws Exception

Retrieves the record from the given position

Parameters:

pos - The position to retrieve the record from

Returns:

The retrieved record

Throws:

Exception - An unrecoverable for the operation error occured

clear

public void clear()

Clears the underlying structs