Package com.pnfsoftware.jeb.util.io

Class RotatingFileOutputStream

java.lang.Object

java.io.OutputStream

com.pnfsoftware.jeb.util.io.RotatingFileOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class RotatingFileOutputStream
extends OutputStream

Output stream whose sinks are a series of files. When the output exceeds the maximum file count and maximum size per file, it gets rotated: older output gets deleted to make room for more recent output.

Constructor Summary

Constructors

Constructor	Description
RotatingFileOutputStream(File folder, String basename, int rotFileCount, long rotFileSize)	Create a rotating file(s) output stream.
RotatingFileOutputStream(File folder, String basename, int rotFileCount, long rotFileSize, boolean buffered, boolean appendToExisting)	Create a rotating file(s) output stream.

Method Summary

Modifier and Type	Method	Description
void	close()
void	flush()
protected String	generateFileSuffix(int fileIndex)	The file suffix appended to the base filename for additional file.
File	getAdditionalOutputFile(int i)	Retrieve an additional output file by index.
File	getOutputFile()	Retrieve the principal (first) output file.
int	getRotatingFileCount()	Get the configured number of rotated files to keep.
long	getRotatingFileSize()	Get the configured maximum size of the active output file.
long	getRotationCount()	Get the number of completed rotations.
boolean	isBuffered()	Determine whether writes are buffered.
void	rotate()	Rotate output files immediately.
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

nullOutputStream, write

Methods inherited from class java.lang.Object

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

Constructor Details

RotatingFileOutputStream

public RotatingFileOutputStream(File folder,
 String basename,
 int rotFileCount,
 long rotFileSize)
                         throws IOException

Create a rotating file(s) output stream. The stream is buffered, output is appended to existing files (if any).

Parameters:

folder - output folder; use null to denote the current working directory

basename - base file name

rotFileCount - number of rotated files to keep

rotFileSize - maximum size of the active output file

Throws:

IOException - if the initial output file cannot be opened

RotatingFileOutputStream

public RotatingFileOutputStream(File folder,
 String basename,
 int rotFileCount,
 long rotFileSize,
 boolean buffered,
 boolean appendToExisting)
                         throws IOException

Create a rotating file(s) output stream.

Parameters:

folder - output folder; use null to denote the current working directory

basename - base file name, must be non-empty

rotFileCount - >=0 (can be 0 for no rotating output); should be >= 1

rotFileSize - >0 (cannot be negative or "infinite": a maximum file size must be specified to prevent uncontrolled growth)

buffered - enable or disable buffered-writes (recommended for high-frequency writing)

appendToExisting - append to a previously existing file, if any

Throws:

IOException - on IO error

Method Details

getRotatingFileCount

public int getRotatingFileCount()

Get the configured number of rotated files to keep.

Returns:

rotated file count

getRotatingFileSize

public long getRotatingFileSize()

Get the configured maximum size of the active output file.

Returns:

maximum file size in bytes

isBuffered

public boolean isBuffered()

Determine whether writes are buffered.

Returns:

true if buffering is enabled

getRotationCount

public long getRotationCount()

Get the number of completed rotations.

Returns:

rotation count

getOutputFile

public File getOutputFile()

Retrieve the principal (first) output file.

Returns:

active output file

getAdditionalOutputFile

public File getAdditionalOutputFile(int i)
                             throws IOException

Retrieve an additional output file by index.

Parameters:

i - file index, must be in [1, maximum_filecount]

Returns:

rotated output file

Throws:

IOException - if the index is invalid

generateFileSuffix

protected String generateFileSuffix(int fileIndex)

The file suffix appended to the base filename for additional file. Note that the default implementation simply generates a ".N" suffix.

Parameters:

fileIndex - file index

Returns:

generated file suffix

rotate

public void rotate()
            throws IOException

Rotate output files immediately.

Throws:

IOException - if a file cannot be closed, renamed, created, or opened

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
 int off,
 int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException