fr.ifremer.isisfish.logging.io
Class LineReader

java.lang.Object
  fr.ifremer.isisfish.logging.io.LineReader

Direct Known Subclasses:

LineReaderUtil.LevelLineReader, LineReaderUtil.LevelsLineReader, LineReaderUtil.PatternLineReader

public class LineReader
extends Object

A lineReader reads lines from a file using a RandomAccessFile.

To perfrom efficient io operations, we use a OffsetReader to obtain the offset of the first char of a line.

You can create a new LineReader from a previous one, the matchings lines of the new LineReader will all match the parent one (subset LineReader).

Author:

chemit

Field Summary

protected File	file
protected String	id an identifier for the reader
protected long	lastModified last modified time of the file after last synchronization
protected long	length size of the file after last synchronization
protected static org.apache.commons.logging.Log	log
protected OffsetReader	offstReader offset reader used
protected LineReader	parent parent LineReader
protected RandomAccessFile	reader file reader

Constructor Summary

LineReader(File file, OffsetReader offstReader)

LineReader(LineReader parent, OffsetReader offstReader)

Method Summary

void	close() Close the reader.
protected void	ensureOpen()
protected void	finalize()
File	getFile()
String	getId()
long	getNbLines()
OffsetReader	getOffsetReader()
LineReader	getParent()
boolean	isOpen()
boolean	isUpToDate()
boolean	match(String line) Matcher of line for this reader.
void	open() method we must inovke before any access to lines
String	readLine(long position) Read a line from a given position.
String[]	readLine(long position, int length) Read some line(s) from a given position.
String	readLine2(long position) Read a line from a given position.
String[]	readLine2(long position, int length) Read some line(s) from a given position.
void	setId(String id)
String	toString()
void	update() check if reader is up to date, and if not perform an update.

Methods inherited from class java.lang.Object

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

Field Detail

log

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

file

protected File file

reader

protected RandomAccessFile reader

file reader

length

protected long length

size of the file after last synchronization

lastModified

protected long lastModified

last modified time of the file after last synchronization

parent

protected LineReader parent

parent LineReader

offstReader

protected OffsetReader offstReader

offset reader used

id

protected String id

an identifier for the reader

Constructor Detail

LineReader

public LineReader(LineReader parent,
                  OffsetReader offstReader)

LineReader

public LineReader(File file,
                  OffsetReader offstReader)

Method Detail

open

public void open()
          throws IOException

method we must inovke before any access to lines

Throws:

IOException - if any probem while opening reader

close

public void close()
           throws IOException

Close the reader.

Throws:

IOException - if any problem while closing reader

readLine2

public String readLine2(long position)
                 throws IOException

Read a line from a given position.

Parameters:

position - position of the line in the file

Returns:

the line found, or null

Throws:

IOException - if any problem while reading

readLine2

public String[] readLine2(long position,
                          int length)
                   throws IOException

Read some line(s) from a given position.

Parameters:

position - position of the line in the file

length - the number of lines we want

Returns:

the array of lines required, or null if eof

Throws:

IOException - if any problem while reading

readLine

public String readLine(long position)
                throws IOException

Read a line from a given position.

Parameters:

position - position of the line in the file

Returns:

the line found, or null

Throws:

IOException - if any problem while reading

readLine

public String[] readLine(long position,
                         int length)
                  throws IOException

Read some line(s) from a given position.

Parameters:

position - position of the line in the file

length - the number of lines we want

Returns:

the array of lines required, or null if eof

Throws:

IOException - if any problem while reading

update

public void update()
            throws IOException

check if reader is up to date, and if not perform an update.

Throws:

IOException - if any problem while updating

match

public boolean match(String line)

Matcher of line for this reader.

Parameters:

line - the line to be accepted by this line reader

Returns:

true if the line must be used,false otherwise

getNbLines

public long getNbLines()

Returns:

the number of lines found in the file

getFile

public File getFile()

Returns:

the file used to read lines

getOffsetReader

public OffsetReader getOffsetReader()

Returns:

the offset reader used to obtain offsets.

getParent

public LineReader getParent()

Returns:

the parent LineReader, or null if none

isUpToDate

public boolean isUpToDate()

Returns:

true if file is up to date,false otherwise

toString

public String toString()

Overrides:

toString in class Object

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

ensureOpen

protected void ensureOpen()

isOpen

public boolean isOpen()

getId

public String getId()

setId

public void setId(String id)