fr.ifremer.isisfish.logging.io
Class FileOffsetReader

java.lang.Object
  fr.ifremer.isisfish.logging.io.OffsetReader
      fr.ifremer.isisfish.logging.io.FileOffsetReader

public class FileOffsetReader
extends OffsetReader

A simple implementation of OffsetReader using a file for dealing with offsets.

The offset of lines are pre-computed in a file offsetFile, generated by createOffsets(LineReader). or createOffsets(LineReader , LineReader).

Author:

chemit

Field Summary

protected static org.apache.commons.logging.Log	log
protected java.io.File	offsetFile offset file to read
protected java.io.RandomAccessFile	offsetReader offset file reader
protected java.io.RandomAccessFile	writer writer used while creation or update

Fields inherited from class fr.ifremer.isisfish.logging.io.OffsetReader

nbLines

Constructor Summary

FileOffsetReader(java.io.File file)

Method Summary

void	close() Close the reader
protected long	createOffsets(LineReader lineReader)
protected long	createOffsets(LineReader lineReader, LineReader parent)
void	deleteOffsetFile() delete offset resources
long	getOffset(long position) Obtain an offset for a position
protected boolean	needCreate()
void	open(LineReader reader) Open the reader
protected void	storeOffset(long position, long offset) Save the offset of the line for a given position
java.lang.String	toString()
void	update(LineReader lineReader) Update the reader

Methods inherited from class fr.ifremer.isisfish.logging.io.OffsetReader

createOffsetsForLog, getNbLines, isLogEntry, readLine

Methods inherited from class java.lang.Object

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

Field Detail

log

protected static final org.apache.commons.logging.Log log

offsetFile

protected java.io.File offsetFile

offset file to read

offsetReader

protected java.io.RandomAccessFile offsetReader

offset file reader

writer

protected java.io.RandomAccessFile writer

writer used while creation or update

Constructor Detail

FileOffsetReader

public FileOffsetReader(java.io.File file)

Method Detail

getOffset

public long getOffset(long position)
               throws java.io.IOException

Description copied from class: OffsetReader

Obtain an offset for a position

Specified by:

getOffset in class OffsetReader

Parameters:

position - position of the line

Returns:

the offset of the first car of the given line

Throws:

java.io.IOException - todo

open

public void open(LineReader reader)
          throws java.io.IOException

Description copied from class: OffsetReader

Open the reader

Overrides:

open in class OffsetReader

Parameters:

reader - LineReader linked with this reader

Throws:

java.io.IOException - if any problem while opening

close

public void close()
           throws java.io.IOException

Description copied from class: OffsetReader

Close the reader

Overrides:

close in class OffsetReader

Throws:

java.io.IOException - if any problem while closing

update

public void update(LineReader lineReader)
            throws java.io.IOException

Description copied from class: OffsetReader

Update the reader

Overrides:

update in class OffsetReader

Parameters:

lineReader - lineReader linked with this reader

Throws:

java.io.IOException - if any problem while updating

deleteOffsetFile

public void deleteOffsetFile()

Description copied from class: OffsetReader

delete offset resources

Overrides:

deleteOffsetFile in class OffsetReader

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

storeOffset

protected void storeOffset(long position,
                           long offset)
                    throws java.io.IOException

Description copied from class: OffsetReader

Save the offset of the line for a given position

Specified by:

storeOffset in class OffsetReader

Parameters:

position - current line position

offset - current offset of line

Throws:

java.io.IOException - if any problem while storing

needCreate

protected boolean needCreate()
                      throws java.io.IOException

Specified by:

needCreate in class OffsetReader

Returns:

true if the reader need to create his internal datas.

Throws:

java.io.IOException - if any problme while creating

createOffsets

protected long createOffsets(LineReader lineReader)
                      throws java.io.IOException

Overrides:

createOffsets in class OffsetReader

Throws:

java.io.IOException

createOffsets

protected long createOffsets(LineReader lineReader,
                             LineReader parent)
                      throws java.io.IOException

Overrides:

createOffsets in class OffsetReader

Throws:

java.io.IOException