Class ChannelBuffers


  • public final class ChannelBuffers
    extends Object
    Creates a new ChannelBuffer by allocating new space or by wrapping or copying existing byte arrays, byte buffers and a string.

    Use static import

    This classes is intended to be used with Java 5 static import statement:
     import static org.jboss.netty.buffer.ChannelBuffers.*;
    
     ChannelBuffer heapBuffer    = buffer(128);
     ChannelBuffer directBuffer  = directBuffer(256);
     ChannelBuffer dynamicBuffer = dynamicBuffer(512);
     ChannelBuffer wrappedBuffer = wrappedBuffer(new byte[128], new byte[256]);
     ChannelBuffer copiedBuffe r = copiedBuffer(ByteBuffer.allocate(128));
     

    Allocating a new buffer

    Three buffer types are provided out of the box.
    • buffer(int) allocates a new fixed-capacity heap buffer.
    • directBuffer(int) allocates a new fixed-capacity direct buffer.
    • dynamicBuffer(int) allocates a new dynamic-capacity heap buffer, whose capacity increases automatically as needed by a write operation.

    Creating a wrapped buffer

    Wrapped buffer is a buffer which is a view of one or more existing byte arrays and byte buffers. Any changes in the content of the original array or buffer will be visible in the wrapped buffer. Various wrapper methods are provided and their name is all wrappedBuffer(). You might want to take a look at the methods that accept varargs closely if you want to create a buffer which is composed of more than one array to reduce the number of memory copy.

    Creating a copied buffer

    Copied buffer is a deep copy of one or more existing byte arrays, byte buffers or a string. Unlike a wrapped buffer, there's no shared data between the original data and the copied buffer. Various copy methods are provided and their name is all copiedBuffer(). It is also convenient to use this operation to merge multiple buffers into one buffer.

    Miscellaneous utility methods

    This class also provides various utility methods to help implementation of a new buffer type, generation of hex dump and swapping an integer's byte order.
    • Field Detail

      • BIG_ENDIAN

        public static final ByteOrder BIG_ENDIAN
        Big endian byte order.
      • LITTLE_ENDIAN

        public static final ByteOrder LITTLE_ENDIAN
        Little endian byte order.
      • EMPTY_BUFFER

        public static final ChannelBuffer EMPTY_BUFFER
        A buffer whose capacity is 0.
    • Method Detail

      • buffer

        public static ChannelBuffer buffer​(int capacity)
        Creates a new big-endian Java heap buffer with the specified capacity. The new buffer's readerIndex and writerIndex are 0.
      • buffer

        public static ChannelBuffer buffer​(ByteOrder endianness,
                                           int capacity)
        Creates a new Java heap buffer with the specified endianness and capacity. The new buffer's readerIndex and writerIndex are 0.
      • directBuffer

        public static ChannelBuffer directBuffer​(int capacity)
        Creates a new big-endian direct buffer with the specified capacity. The new buffer's readerIndex and writerIndex are 0.
      • directBuffer

        public static ChannelBuffer directBuffer​(ByteOrder endianness,
                                                 int capacity)
        Creates a new direct buffer with the specified endianness and capacity. The new buffer's readerIndex and writerIndex are 0.
      • dynamicBuffer

        public static ChannelBuffer dynamicBuffer()
        Creates a new big-endian dynamic buffer whose estimated data length is 256 bytes. The new buffer's readerIndex and writerIndex are 0.
      • dynamicBuffer

        public static ChannelBuffer dynamicBuffer​(int estimatedLength)
        Creates a new big-endian dynamic buffer with the specified estimated data length. More accurate estimation yields less unexpected reallocation overhead. The new buffer's readerIndex and writerIndex are 0.
      • dynamicBuffer

        public static ChannelBuffer dynamicBuffer​(ByteOrder endianness,
                                                  int estimatedLength)
        Creates a new dynamic buffer with the specified endianness and the specified estimated data length. More accurate estimation yields less unexpected reallocation overhead. The new buffer's readerIndex and writerIndex are 0.
      • dynamicBuffer

        public static ChannelBuffer dynamicBuffer​(int estimatedLength,
                                                  ChannelBufferFactory factory)
        Creates a new big-endian dynamic buffer with the specified estimated data length using the specified factory. More accurate estimation yields less unexpected reallocation overhead. The new buffer's readerIndex and writerIndex are 0.
      • dynamicBuffer

        public static ChannelBuffer dynamicBuffer​(ByteOrder endianness,
                                                  int estimatedLength,
                                                  ChannelBufferFactory factory)
        Creates a new dynamic buffer with the specified endianness and the specified estimated data length using the specified factory. More accurate estimation yields less unexpected reallocation overhead. The new buffer's readerIndex and writerIndex are 0.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(byte[] array)
        Creates a new big-endian buffer which wraps the specified array. A modification on the specified array's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ByteOrder endianness,
                                                  byte[] array)
        Creates a new buffer which wraps the specified array with the specified endianness. A modification on the specified array's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(byte[] array,
                                                  int offset,
                                                  int length)
        Creates a new big-endian buffer which wraps the sub-region of the specified array. A modification on the specified array's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ByteOrder endianness,
                                                  byte[] array,
                                                  int offset,
                                                  int length)
        Creates a new buffer which wraps the sub-region of the specified array with the specified endianness. A modification on the specified array's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ByteBuffer buffer)
        Creates a new buffer which wraps the specified NIO buffer's current slice. A modification on the specified buffer's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ChannelBuffer buffer)
        Creates a new buffer which wraps the specified buffer's readable bytes. A modification on the specified buffer's content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(byte[]... arrays)
        Creates a new big-endian composite buffer which wraps the specified arrays without copying them. A modification on the specified arrays' content will be visible to the returned buffer.
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ByteOrder endianness,
                                                  byte[]... arrays)
        Creates a new composite buffer which wraps the specified arrays without copying them. A modification on the specified arrays' content will be visible to the returned buffer.
        Parameters:
        endianness - the endianness of the new buffer
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ChannelBuffer... buffers)
        Creates a new composite buffer which wraps the readable bytes of the specified buffers without copying them. A modification on the content of the specified buffers will be visible to the returned buffer.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(boolean gathering,
                                                  ChannelBuffer... buffers)
        Creates a new composite buffer which wraps the readable bytes of the specified buffers without copying them. A modification on the content of the specified buffers will be visible to the returned buffer. If gathering is true then gathering writes will be used when ever possible.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(ByteBuffer... buffers)
        Creates a new composite buffer which wraps the slices of the specified NIO buffers without copying them. A modification on the content of the specified buffers will be visible to the returned buffer.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • wrappedBuffer

        public static ChannelBuffer wrappedBuffer​(boolean gathering,
                                                  ByteBuffer... buffers)
        Creates a new composite buffer which wraps the slices of the specified NIO buffers without copying them. A modification on the content of the specified buffers will be visible to the returned buffer. If gathering is true then gathering writes will be used when ever possible.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(byte[] array)
        Creates a new big-endian buffer whose content is a copy of the specified array. The new buffer's readerIndex and writerIndex are 0 and array.length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 byte[] array)
        Creates a new buffer with the specified endianness whose content is a copy of the specified array. The new buffer's readerIndex and writerIndex are 0 and array.length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(byte[] array,
                                                 int offset,
                                                 int length)
        Creates a new big-endian buffer whose content is a copy of the specified array's sub-region. The new buffer's readerIndex and writerIndex are 0 and the specified length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 byte[] array,
                                                 int offset,
                                                 int length)
        Creates a new buffer with the specified endianness whose content is a copy of the specified array's sub-region. The new buffer's readerIndex and writerIndex are 0 and the specified length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteBuffer buffer)
        Creates a new buffer whose content is a copy of the specified buffer's current slice. The new buffer's readerIndex and writerIndex are 0 and buffer.remaining respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ChannelBuffer buffer)
        Creates a new buffer whose content is a copy of the specified buffer's readable bytes. The new buffer's readerIndex and writerIndex are 0 and buffer.readableBytes respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(byte[]... arrays)
        Creates a new big-endian buffer whose content is a merged copy of the specified arrays. The new buffer's readerIndex and writerIndex are 0 and the sum of all arrays' length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 byte[]... arrays)
        Creates a new buffer with the specified endianness whose content is a merged copy of the specified arrays. The new buffer's readerIndex and writerIndex are 0 and the sum of all arrays' length respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ChannelBuffer... buffers)
        Creates a new buffer whose content is a merged copy of the specified buffers' readable bytes. The new buffer's readerIndex and writerIndex are 0 and the sum of all buffers' readableBytes respectively.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteBuffer... buffers)
        Creates a new buffer whose content is a merged copy of the specified buffers' slices. The new buffer's readerIndex and writerIndex are 0 and the sum of all buffers' remaining respectively.
        Throws:
        IllegalArgumentException - if the specified buffers' endianness are different from each other
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(CharSequence string,
                                                 Charset charset)
        Creates a new big-endian buffer whose content is the specified string encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(CharSequence string,
                                                 int offset,
                                                 int length,
                                                 Charset charset)
        Creates a new big-endian buffer whose content is a subregion of the specified string encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 CharSequence string,
                                                 Charset charset)
        Creates a new buffer with the specified endianness whose content is the specified string encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 CharSequence string,
                                                 int offset,
                                                 int length,
                                                 Charset charset)
        Creates a new buffer with the specified endianness whose content is a subregion of the specified string encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(char[] array,
                                                 Charset charset)
        Creates a new big-endian buffer whose content is the specified array encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(char[] array,
                                                 int offset,
                                                 int length,
                                                 Charset charset)
        Creates a new big-endian buffer whose content is a subregion of the specified array encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 char[] array,
                                                 Charset charset)
        Creates a new buffer with the specified endianness whose content is the specified array encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • copiedBuffer

        public static ChannelBuffer copiedBuffer​(ByteOrder endianness,
                                                 char[] array,
                                                 int offset,
                                                 int length,
                                                 Charset charset)
        Creates a new buffer with the specified endianness whose content is a subregion of the specified array encoded in the specified charset. The new buffer's readerIndex and writerIndex are 0 and the length of the encoded string respectively.
      • unmodifiableBuffer

        public static ChannelBuffer unmodifiableBuffer​(ChannelBuffer buffer)
        Creates a read-only buffer which disallows any modification operations on the specified buffer. The new buffer has the same readerIndex and writerIndex with the specified buffer.
      • hexDump

        public static String hexDump​(ChannelBuffer buffer,
                                     int fromIndex,
                                     int length)
        Returns a hex dump of the specified buffer's sub-region.
      • hashCode

        public static int hashCode​(ChannelBuffer buffer)
        Calculates the hash code of the specified buffer. This method is useful when implementing a new buffer type.
      • equals

        public static boolean equals​(ChannelBuffer bufferA,
                                     ChannelBuffer bufferB)
        Returns true if and only if the two specified buffers are identical to each other as described in ChannelBuffer#equals(Object). This method is useful when implementing a new buffer type.
      • swapShort

        public static short swapShort​(short value)
        Toggles the endianness of the specified 16-bit short integer.
      • swapMedium

        public static int swapMedium​(int value)
        Toggles the endianness of the specified 24-bit medium integer.
      • swapInt

        public static int swapInt​(int value)
        Toggles the endianness of the specified 32-bit integer.
      • swapLong

        public static long swapLong​(long value)
        Toggles the endianness of the specified 64-bit long integer.