Package org.jboss.netty.buffer

Class 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.

    • Field Detail

      • bigEndianLock

        private final java.lang.Object bigEndianLock

      • littleEndianLock

        private final java.lang.Object littleEndianLock

      • preallocatedBufCapacity

        private final int preallocatedBufCapacity

      • preallocatedBEBufPos

        private int preallocatedBEBufPos

      • preallocatedLEBufPos

        private int preallocatedLEBufPos

    • 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​(java.nio.ByteOrder defaultOrder)
        Creates a new factory with the specified default ByteOrder.
        Parameters:
        defaultOrder - the default ByteOrder of this factory

      • DirectChannelBufferFactory

        public DirectChannelBufferFactory​(java.nio.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​(java.nio.ByteOrder defaultEndianness)

      • getBuffer

        public ChannelBuffer getBuffer​(java.nio.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​(java.nio.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​(java.nio.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

      • allocateBigEndianBuffer

        private ChannelBuffer allocateBigEndianBuffer​(int capacity)

      • allocateLittleEndianBuffer

        private ChannelBuffer allocateLittleEndianBuffer​(int capacity)