de.lmu.ifi.dbs.elki.utilities.io

Class LineReader

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.io.LineReader

All Implemented Interfaces:

java.lang.AutoCloseable

public class LineReader
extends java.lang.Object
implements java.lang.AutoCloseable

Fast class to read a file, line per line. Lines must be split using Unix newlines \n, linefeeds \r are ignored. This is a rather minimal implementation, which supposedly pays off in performance. In particular, this class allows recycling the buffer, which will yield less object allocations and thus less garbage collection. Usage example:

 StringBuilder buf = new StringBuilder();
 LineReader reader = new LineReader(inputStream);
 // Clear buffer, and append next line.
 while(reader.readLine(buf.setLength(0))) {
   // process string in buffer.
 }
 

Since:

0.7.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
(package private) char[]	buffer Character buffer
(package private) static int	BUFFER_SIZE Default buffer size to use
(package private) int	end Current position, and length of buffer
(package private) java.io.Reader	in Input stream to read from
(package private) int	pos Current position, and length of buffer

Constructor Summary

Constructors

Constructor and Description
LineReader(java.io.InputStream in) Constructor
LineReader(java.io.InputStream in, int buffersize) Constructor
LineReader(java.io.Reader in) Constructor
LineReader(java.io.Reader in, int buffersize) Constructor

Method Summary

Modifier and Type	Method and Description
void	close()
boolean	readLine(java.lang.Appendable buf) Read a line into the given buffer.

Methods inherited from class java.lang.Object

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

Field Detail

BUFFER_SIZE

static final int BUFFER_SIZE

Default buffer size to use

See Also:

Constant Field Values

in

java.io.Reader in

Input stream to read from

buffer

char[] buffer

Character buffer

pos

int pos

Current position, and length of buffer

end

int end

Current position, and length of buffer

Constructor Detail

LineReader

public LineReader(java.io.InputStream in)

Constructor

Parameters:

in - Stream

LineReader

public LineReader(java.io.Reader in)

Constructor

Parameters:

in - Reader

LineReader

public LineReader(java.io.InputStream in,
                  int buffersize)

Constructor

Parameters:

in - Reader

buffersize - Buffer size

LineReader

public LineReader(java.io.Reader in,
                  int buffersize)

Constructor

Parameters:

in - Reader

buffersize - Buffer size

Method Detail

readLine

public boolean readLine(java.lang.Appendable buf)
                 throws java.io.IOException

Read a line into the given buffer.

Parameters:

buf - Buffer.

Returns:

true if some characters have been read.

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException