org.jboss.netty.buffer
Class DirectChannelBufferFactory

java.lang.Object
  org.jboss.netty.buffer.AbstractChannelBufferFactory
      org.jboss.netty.buffer.DirectChannelBufferFactory

All Implemented Interfaces:

ChannelBufferFactory

public class DirectChannelBufferFactory
extends AbstractChannelBufferFactory

A ChannelBufferFactory which pre-allocates a large chunk of direct buffer and returns its slice on demand. Direct buffers are reclaimed via ReferenceQueue in most JDK implementations, and therefore they are deallocated less efficiently than an ordinary heap buffer. Consequently, a user will get OutOfMemoryError when one tries to allocate small direct buffers more often than the GC throughput of direct buffers, which is much lower than the GC throughput of heap buffers. This factory avoids this problem by allocating a large chunk of pre-allocated direct buffer and reducing the number of the garbage collected internal direct buffer objects.

Version:

$Rev: 2293 $, $Date: 2010-06-01 17:38:51 +0900 (Tue, 01 Jun 2010) $

Author:

The Netty Project, Trustin Lee

Constructor Summary

DirectChannelBufferFactory()
Creates a new factory whose default ByteOrder is ByteOrder.BIG_ENDIAN.

DirectChannelBufferFactory(ByteOrder defaultOrder)
Creates a new factory with the specified default ByteOrder.

DirectChannelBufferFactory(ByteOrder defaultOrder, int preallocatedBufferCapacity)
Creates a new factory with the specified default ByteOrder.

DirectChannelBufferFactory(int preallocatedBufferCapacity)
Creates a new factory whose default ByteOrder is ByteOrder.BIG_ENDIAN.

Method Summary

ChannelBuffer	getBuffer(ByteBuffer nioBuffer) Returns a ChannelBuffer whose content is equal to the sub-region of the specified nioBuffer.
ChannelBuffer	getBuffer(ByteOrder order, byte[] array, int offset, int length) Returns a ChannelBuffer whose content is equal to the sub-region of the specified array.
ChannelBuffer	getBuffer(ByteOrder order, int capacity) Returns a ChannelBuffer with the specified endianness and capacity.
static ChannelBufferFactory	getInstance()
static ChannelBufferFactory	getInstance(ByteOrder defaultEndianness)

Methods inherited from class org.jboss.netty.buffer.AbstractChannelBufferFactory

getBuffer, getBuffer, getDefaultOrder

Methods inherited from class java.lang.Object

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

Constructor Detail

DirectChannelBufferFactory

public DirectChannelBufferFactory()

Creates a new factory whose default ByteOrder is ByteOrder.BIG_ENDIAN.

DirectChannelBufferFactory

public DirectChannelBufferFactory(int preallocatedBufferCapacity)

Creates a new factory whose default ByteOrder is ByteOrder.BIG_ENDIAN.

DirectChannelBufferFactory

public DirectChannelBufferFactory(ByteOrder defaultOrder)

Creates a new factory with the specified default ByteOrder.

Parameters:

defaultOrder - the default ByteOrder of this factory

DirectChannelBufferFactory

public DirectChannelBufferFactory(ByteOrder defaultOrder,
                                  int preallocatedBufferCapacity)

Creates a new factory with the specified default ByteOrder.

Parameters:

defaultOrder - the default ByteOrder of this factory

Method Detail

getInstance

public static ChannelBufferFactory getInstance()

getInstance

public static ChannelBufferFactory getInstance(ByteOrder defaultEndianness)

getBuffer

public ChannelBuffer getBuffer(ByteOrder order,
                               int capacity)

Description copied from interface: ChannelBufferFactory

Returns a ChannelBuffer with the specified endianness and capacity.

Parameters:

order - the endianness of the returned ChannelBuffer

capacity - the capacity of the returned ChannelBuffer

Returns:

a ChannelBuffer with the specified endianness and capacity, whose readerIndex and writerIndex are 0

getBuffer

public ChannelBuffer getBuffer(ByteOrder order,
                               byte[] array,
                               int offset,
                               int length)

Description copied from interface: ChannelBufferFactory

Returns a ChannelBuffer whose content is equal to the sub-region of the specified array. Depending on the factory implementation, the returned buffer could wrap the array or create a new copy of the array.

Parameters:

order - the endianness of the returned ChannelBuffer

array - the byte array

offset - the offset of the byte array

length - the length of the byte array

Returns:

a ChannelBuffer with the specified content, whose readerIndex and writerIndex are 0 and (length - offset) respectively

getBuffer

public ChannelBuffer getBuffer(ByteBuffer nioBuffer)

Description copied from interface: ChannelBufferFactory

Returns a ChannelBuffer whose content is equal to the sub-region of the specified nioBuffer. Depending on the factory implementation, the returned buffer could wrap the nioBuffer or create a new copy of the nioBuffer.

Parameters:

nioBuffer - the NIO ByteBuffer

Returns:

a ChannelBuffer with the specified content, whose readerIndex and writerIndex are 0 and nioBuffer.remaining() respectively