This subinterface of
Channel defines a single key read(
)
method which reads bytes from the channel and stores them in the
specified ByteBuffer, updating the buffer position
as it does so. read( ) attempts to read as many
bytes as will fit in the specified buffer, (see
Buffer.remaining( )) but may read fewer than this.
If the channel is a nonblocking channel, for example, the
read( ) will return immediately, even if there are
no bytes available to be read. read( ) returns the
number of bytes actually read (which may be zero in the nonblocking
case), or returns -1 if there are no more bytes to be read in the
channel (if, for example, the end of a file has been reached, or the
other end of a socket has been closed.)
read( ) is declared to throw an
IOException. More specifically, it may throw a
ClosedChannelException if the channel is closed.
If the channel is closed asynchronously, or if a blocked thread is
interrupted, the read( ) method may terminate with
an AsynchronousCloseException or a
ClosedByInterruptException. read(
) may also throw an unchecked
NonReadableChannelException if it is called on a
channel that was not opened or configured to allow reading.
ReadableByteChannel implementations are required
to be thread-safe: only one thread may perform a read operation on a
channel at a time. If a read operation is in progress, then any call
to read( ) will block until the in-progress
operation completes. Some channel implementations may allow read and
write operations to proceed concurrently, but none will allow two
read operations to proceed at the same time.
public interface ReadableByteChannel extends Channel {
// Public Instance Methods
int read(java.nio.ByteBuffer dst) throws java.io.IOException;
}
