GatheringByteChannel (Java SE 15 & JDK 15) (original) (raw)

All Superinterfaces:

[AutoCloseable](../../lang/AutoCloseable.html "interface in java.lang"), [Channel](Channel.html "interface in java.nio.channels"), [Closeable](../../io/Closeable.html "interface in java.io"), [WritableByteChannel](WritableByteChannel.html "interface in java.nio.channels")

All Known Implementing Classes:

[DatagramChannel](DatagramChannel.html "class in java.nio.channels"), [FileChannel](FileChannel.html "class in java.nio.channels"), [Pipe.SinkChannel](Pipe.SinkChannel.html "class in java.nio.channels"), [SocketChannel](SocketChannel.html "class in java.nio.channels")

public interface GatheringByteChannel extends WritableByteChannel

A channel that can write bytes from a sequence of buffers.

A gathering write operation writes, in a single invocation, a sequence of bytes from one or more of a given sequence of buffers. Gathering writes are often useful when implementing network protocols or file formats that, for example, group data into segments consisting of one or more fixed-length headers followed by a variable-length body. Similar_scattering_ read operations are defined in the ScatteringByteChannel interface.

Since:

1.4

• Method Summary

• Method Details

  • write

  Writes a sequence of bytes to this channel from a subsequence of the given buffers.
  An attempt is made to write up to r bytes to this channel, where r is the total number of bytes remaining in the specified subsequence of the given buffer array, that is,

  srcs[offset].remaining()
  + srcs[offset+1].remaining()
  + ... + srcs[offset+length-1].remaining()
  at the moment that this method is invoked.
  Suppose that a byte sequence of length n is written, where0 <= n <= r. Up to the first srcs[offset].remaining() bytes of this sequence are written from buffer srcs[offset], up to the nextsrcs[offset+1].remaining() bytes are written from buffersrcs[offset+1], and so forth, until the entire byte sequence is written. As many bytes as possible are written from each buffer, hence the final position of each updated buffer, except the last updated buffer, is guaranteed to be equal to that buffer's limit.
  Unless otherwise specified, a write operation will return only after writing all of the r requested bytes. Some types of channels, depending upon their state, may write only some of the bytes or possibly none at all. A socket channel in non-blocking mode, for example, cannot write any more bytes than are free in the socket's output buffer.
  This method may be invoked at any time. If another thread has already initiated a write operation upon this channel, however, then an invocation of this method will block until the first operation is complete.
  Parameters:
  srcs - The buffers from which bytes are to be retrieved
  offset - The offset within the buffer array of the first buffer from which bytes are to be retrieved; must be non-negative and no larger than srcs.length
length - The maximum number of buffers to be accessed; must be non-negative and no larger thansrcs.length - offset
  Returns:
  The number of bytes written, possibly zero
  Throws:
  [IndexOutOfBoundsException](../../lang/IndexOutOfBoundsException.html "class in java.lang") - If the preconditions on the offset and length parameters do not hold
  [NonWritableChannelException](NonWritableChannelException.html "class in java.nio.channels") - If this channel was not opened for writing
  [ClosedChannelException](ClosedChannelException.html "class in java.nio.channels") - If this channel is closed
  [AsynchronousCloseException](AsynchronousCloseException.html "class in java.nio.channels") - If another thread closes this channel while the write operation is in progress
  [ClosedByInterruptException](ClosedByInterruptException.html "class in java.nio.channels") - If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
  [IOException](../../io/IOException.html "class in java.io") - If some other I/O error occurs

  • write

  Writes a sequence of bytes to this channel from the given buffers.
  An invocation of this method of the form c.write(srcs) behaves in exactly the same manner as the invocation

  c.write(srcs, 0, srcs.length);
  Parameters:
  srcs - The buffers from which bytes are to be retrieved
  Returns:
  The number of bytes written, possibly zero
  Throws:
  [NonWritableChannelException](NonWritableChannelException.html "class in java.nio.channels") - If this channel was not opened for writing
  [ClosedChannelException](ClosedChannelException.html "class in java.nio.channels") - If this channel is closed
  [AsynchronousCloseException](AsynchronousCloseException.html "class in java.nio.channels") - If another thread closes this channel while the write operation is in progress
  [ClosedByInterruptException](ClosedByInterruptException.html "class in java.nio.channels") - If another thread interrupts the current thread while the write operation is in progress, thereby closing the channel and setting the current thread's interrupt status
  [IOException](../../io/IOException.html "class in java.io") - If some other I/O error occurs