Class IovArray

java.lang.Object
io.netty.channel.unix.IovArray
All Implemented Interfaces:
ChannelOutboundBuffer.MessageProcessor
public final class IovArray extends Object implements ChannelOutboundBuffer.MessageProcessor
Represent an array of struct array and so can be passed directly over via JNI without the need to do any more array copies. The buffers are written out directly into direct memory to match the struct iov. See also man writev. 
struct iovec {
  void  *iov_base;
  size_t iov_len;
};
See also Efficient JNI programming IV: Wrapping native data objects.

  • Field Details

    • IOV_SIZE

      public static final int IOV_SIZE
      The size of an iovec struct in bytes. This is calculated as we have 2 entries each of the size of the address.

  • Constructor Details

    • IovArray

      @Deprecated public IovArray()
      Deprecated.
      Use IovArray(int) instead.

    • IovArray

      public IovArray(int numEntries)
      Allocate an IovArray with enough room for the given number of entries (not bytes).
      Parameters:
      numEntries - The desired number of entries in the IovArray.

    • IovArray

      @Deprecated public IovArray(ByteBuf memory)
      Deprecated.
      Use IovArray(int) instead.
      Parameters:
      memory - The underlying memory.

  • Method Details

    • clear

      public void clear()

    • add

      @Deprecated public boolean add(ByteBuf buf)
      Deprecated.
      Use add(ByteBuf, int, int)

    • add

      public boolean add(ByteBuf buf, int offset, int len)

    • isFull

      public boolean isFull()
      Return true if there is no more space left in the IovArray.
      Returns:
      full or not.

    • count

      public int count()
      Returns the number if iov entries.

    • size

      public long size()
      Returns the size in bytes

    • maxBytes

      public void maxBytes(long maxBytes)
      Set the maximum amount of bytes that can be added to this IovArray via add(ByteBuf, int, int)

      This will not impact the existing state of the IovArray, and only applies to subsequent calls to add(ByteBuf).

      In order to ensure some progress is made at least one ByteBuf will be accepted even if it's size exceeds this value.

      Parameters:
      maxBytes - the maximum amount of bytes that can be added to this IovArray.

    • maxCount

      public void maxCount(int maxCount)
      Set the maximum amount of buffers that can be added to this IovArray via add(ByteBuf, int, int)

      This will not impact the existing state of the IovArray, and only applies to subsequent calls to add(ByteBuf).

      Parameters:
      maxCount - the maximum amount of bytes that can be added to this IovArray.

    • maxBytes

      public long maxBytes()
      Get the maximum amount of bytes that can be added to this IovArray.
      Returns:
      the maximum amount of bytes that can be added to this IovArray.

    • maxCount

      public int maxCount()
      Get the maximum amount of buffers that can be added to this IovArray.
      Returns:
      the maximum amount of buffers that can be added to this IovArray.

    • memoryAddress

      public long memoryAddress(int offset)
      Returns the memoryAddress for the given offset.

    • release

      public void release()
      Release the IovArray. Once release further using of it may crash the JVM!

    • processMessage

      public boolean processMessage(Object msg) throws Exception
      Description copied from interface: ChannelOutboundBuffer.MessageProcessor
      Will be called for each flushed message until it either there are no more flushed messages or this method returns false.
      Specified by:
      processMessage in interface ChannelOutboundBuffer.MessageProcessor
      Throws:
      Exception