Class MemoryMappedFileManager

java.lang.Object

org.apache.logging.log4j.core.appender.AbstractManager

org.apache.logging.log4j.core.appender.OutputStreamManager

org.apache.logging.log4j.core.appender.MemoryMappedFileManager

All Implemented Interfaces:

AutoCloseable, ByteBufferDestination

public class MemoryMappedFileManager
extends OutputStreamManager

Extends OutputStreamManager but instead of using a buffered output stream, this class maps a region of a file into memory and writes to this memory region.

Since:

2.1

See Also:

• Things to Know about Memory Mapped File in Java
• JDK-6893654
• JDK-4724038
• Memory-Mapped MappedByteBuffer or Direct ByteBuffer for DB Implementation?

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	MemoryMappedFileManager.FactoryData	Factory Data.

Nested classes/interfaces inherited from class AbstractManager

AbstractManager.AbstractFactoryData

Field Summary

Fields

Modifier and Type	Field	Description
private final String	advertiseURI
(package private) static final int	DEFAULT_REGION_LENGTH	Default length of region to map.
private final boolean	immediateFlush
private MappedByteBuffer	mappedBuffer
private long	mappingOffset
private static final int	MAX_REMAP_COUNT
private static final double	NANOS_PER_MILLISEC
private final RandomAccessFile	randomAccessFile
private final int	regionLength

Fields inherited from class OutputStreamManager

byteBuffer, layout

Fields inherited from class AbstractManager

count, LOGGER

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MemoryMappedFileManager(RandomAccessFile file, String fileName, OutputStream os, boolean immediateFlush, long position, int regionLength, String advertiseURI, Layout<? extends Serializable> layout, boolean writeHeader)

Method Summary

Modifier and Type	Method	Description
boolean	closeOutputStream()
ByteBuffer	drain(ByteBuffer buf)	Drains the ByteBufferDestination's buffer into the destination.
void	flush()	Flushes any buffers.
protected void	flushBuffer(ByteBuffer buffer)	Drains the ByteBufferDestination's buffer into the destination.
ByteBuffer	getByteBuffer()	Returns this ByteBufferDestination's buffer.
Map<String,String>	getContentFormat()	Gets this FileManager's content format specified by:
static MemoryMappedFileManager	getFileManager(String fileName, boolean append, boolean immediateFlush, int regionLength, String advertiseURI, Layout<? extends Serializable> layout)	Returns the MemoryMappedFileManager.
String	getFileName()	Returns the name of the File being managed.
int	getRegionLength()	Returns the length of the memory mapped region.
Boolean	isEndOfBatch()	Deprecated. end-of-batch on the event is used instead.
boolean	isImmediateFlush()	Returns true if the content of the buffer should be forced to the storage device on every write, false otherwise.
static MappedByteBuffer	mmap(FileChannel fileChannel, String fileName, long start, int size)
private void	remap()
void	setEndOfBatch(boolean endOfBatch)	Deprecated. end-of-batch on the event is used instead.
private static void	unsafeUnmap(MappedByteBuffer mbb)
protected void	write(byte[] bytes, int offset, int length, boolean immediateFlush)	Some output streams synchronize writes while others do not.

Methods inherited from class OutputStreamManager

createOutputStream, flushDestination, getManager, getOutputStream, hasOutputStream, isOpen, releaseSub, setOutputStream, skipFooter, write, write, write, writeBytes, writeBytes, writeFooter, writeHeader, writeToDestination

Methods inherited from class AbstractManager

close, getCount, getLoggerContext, getManager, getManagerCount, getName, getStrSubstitutor, hasManager, log, logDebug, logError, logger, logWarn, narrow, release, stop, updateData

Methods inherited from class Object

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

Field Details

DEFAULT_REGION_LENGTH

static final int DEFAULT_REGION_LENGTH

Default length of region to map.

See Also:

• Constant Field Values

MAX_REMAP_COUNT

private static final int MAX_REMAP_COUNT

See Also:

• Constant Field Values

NANOS_PER_MILLISEC

private static final double NANOS_PER_MILLISEC

See Also:

• Constant Field Values

immediateFlush

private final boolean immediateFlush

regionLength

private final int regionLength

advertiseURI

private final String advertiseURI

randomAccessFile

private final RandomAccessFile randomAccessFile

mappedBuffer

private MappedByteBuffer mappedBuffer

mappingOffset

private long mappingOffset

Constructor Details

MemoryMappedFileManager

protected MemoryMappedFileManager(RandomAccessFile file,
 String fileName,
 OutputStream os,
 boolean immediateFlush,
 long position,
 int regionLength,
 String advertiseURI,
 Layout<? extends Serializable> layout,
 boolean writeHeader)
                           throws IOException

Throws:

IOException

Method Details

getFileManager

public static MemoryMappedFileManager getFileManager(String fileName,
 boolean append,
 boolean immediateFlush,
 int regionLength,
 String advertiseURI,
 Layout<? extends Serializable> layout)

Returns the MemoryMappedFileManager.

Parameters:

fileName - The name of the file to manage.

append - true if the file should be appended to, false if it should be overwritten.

immediateFlush - true if the contents should be flushed to disk on every write

regionLength - The mapped region length.

advertiseURI - the URI to use when advertising the file

layout - The layout.

Returns:

A MemoryMappedFileManager for the File.

isEndOfBatch

@Deprecated
public Boolean isEndOfBatch()

Deprecated.

end-of-batch on the event is used instead.

No longer used, the LogEvent.isEndOfBatch() attribute is used instead.

Returns:

Boolean.FALSE.

setEndOfBatch

@Deprecated
public void setEndOfBatch(boolean endOfBatch)

Deprecated.

end-of-batch on the event is used instead.

No longer used, the LogEvent.isEndOfBatch() attribute is used instead. This method is a no-op.

write

protected void write(byte[] bytes,
 int offset,
 int length,
 boolean immediateFlush)

Description copied from class: OutputStreamManager

Some output streams synchronize writes while others do not. Synchronizing here insures that log events won't be intertwined.

Overrides:

write in class OutputStreamManager

Parameters:

bytes - The serialized Log event.

offset - The offset into the byte array.

length - The number of bytes to write.

immediateFlush - flushes immediately after writing.

remap

private void remap()

flush

public void flush()

Description copied from class: OutputStreamManager

Flushes any buffers.

Overrides:

flush in class OutputStreamManager

closeOutputStream

public boolean closeOutputStream()

Overrides:

closeOutputStream in class OutputStreamManager

mmap

public static MappedByteBuffer mmap(FileChannel fileChannel,
 String fileName,
 long start,
 int size)
                             throws IOException

Throws:

IOException

unsafeUnmap

private static void unsafeUnmap(MappedByteBuffer mbb)
                         throws Exception

Throws:

Exception

getFileName

public String getFileName()

Returns the name of the File being managed.

Returns:

The name of the File being managed.

getRegionLength

public int getRegionLength()

Returns the length of the memory mapped region.

Returns:

the length of the mapped region

isImmediateFlush

public boolean isImmediateFlush()

Returns true if the content of the buffer should be forced to the storage device on every write, false otherwise.

Returns:

whether each write should be force-sync'ed

getContentFormat

public Map<String,String> getContentFormat()

Gets this FileManager's content format specified by:

Key: "fileURI" Value: provided "advertiseURI" param.

Overrides:

getContentFormat in class AbstractManager

Returns:

Map of content format keys supporting FileManager

flushBuffer

protected void flushBuffer(ByteBuffer buffer)

Description copied from class: OutputStreamManager

Drains the ByteBufferDestination's buffer into the destination. By default this calls OutputStreamManager.write(byte[], int, int, boolean) with the buffer contents. The underlying stream is not flushed.

Overrides:

flushBuffer in class OutputStreamManager

See Also:

• OutputStreamManager.flushDestination()

getByteBuffer

public ByteBuffer getByteBuffer()

Description copied from class: OutputStreamManager

Returns this ByteBufferDestination's buffer.

Specified by:

getByteBuffer in interface ByteBufferDestination

Overrides:

getByteBuffer in class OutputStreamManager

Returns:

the buffer

drain

public ByteBuffer drain(ByteBuffer buf)

Description copied from class: OutputStreamManager

Drains the ByteBufferDestination's buffer into the destination. By default this calls OutputStreamManager.flushBuffer(ByteBuffer) with the specified buffer. Subclasses may override.

Do not call this method lightly! For some subclasses this is a very expensive operation. For example, MemoryMappedFileManager will assume this method was called because the end of the mapped region was reached during a text encoding operation and will remap its buffer.

To just flush the buffered contents to the underlying stream, call OutputStreamManager.flushBuffer(ByteBuffer) directly instead.

Specified by:

drain in interface ByteBufferDestination

Overrides:

drain in class OutputStreamManager

Parameters:

buf - the buffer whose contents to write the destination

Returns:

the specified buffer