Java in a Nutshell, 5th Edition [Electronic resources] نسخه متنی

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.

Figure 13-35. java.nio.channels.ReadableByteChannel

public interface

ReadableByteChannel extends Channel {
// Public Instance Methods
int

read (java.nio.ByteBuffer

dst ) throws java.io.IOException;
}

Implementations

ByteChannel,
Pipe.SourceChannel,
ScatteringByteChannel

Passed To

Channels.{newInputStream( ), newReader(
)}, FileChannel.transferFrom( ),
java.util.Scanner.Scanner( )

Returned By

Channels.newChannel( )