Channel

public interface Channel implements Closeable

Known Indirect Subclasses AbstractInterruptibleChannel, AbstractSelectableChannel, AsynchronousByteChannel, AsynchronousChannel, AsynchronousFileChannel, AsynchronousServerSocketChannel, AsynchronousSocketChannel, ByteChannel, DatagramChannel, FileChannel, GatheringByteChannel, InterruptibleChannel, MulticastChannel, NetworkChannel, Pipe.SinkChannel, and 8 others. AbstractInterruptibleChannel Base implementation class for interruptible channels.  AbstractSelectableChannel Base implementation class for selectable channels.  AsynchronousByteChannel An asynchronous channel that can read and write bytes.  AsynchronousChannel A channel that supports asynchronous I/O operations.  AsynchronousFileChannel An asynchronous channel for reading, writing, and manipulating a file.  AsynchronousServerSocketChannel An asynchronous channel for stream-oriented listening sockets.  AsynchronousSocketChannel An asynchronous channel for stream-oriented connecting sockets.  ByteChannel A channel that can read and write bytes.  DatagramChannel A selectable channel for datagram-oriented sockets.  FileChannel A channel for reading, writing, mapping, and manipulating a file.  GatheringByteChannel A channel that can write bytes from a sequence of buffers.  InterruptibleChannel A channel that can be asynchronously closed and interrupted.  MulticastChannel A network channel that supports Internet Protocol (IP) multicasting.  NetworkChannel A channel to a network socket.  Pipe.SinkChannel A channel representing the writable end of a Pipe.  Pipe.SourceChannel A channel representing the readable end of a Pipe.  ReadableByteChannel A channel that can read bytes.  ScatteringByteChannel A channel that can read bytes into a sequence of buffers.  SeekableByteChannel A byte channel that maintains a current position and allows the position to be changed.  SelectableChannel A channel that can be multiplexed via a Selector.  ServerSocketChannel A selectable channel for stream-oriented listening sockets.  SocketChannel A selectable channel for stream-oriented connecting sockets.  WritableByteChannel A channel that can write bytes.

A nexus for I/O operations.

A channel represents an open connection to an entity such as a hardware device, a file, a network socket, or a program component that is capable of performing one or more distinct I/O operations, for example reading or writing.

A channel is either open or closed. A channel is open upon creation, and once closed it remains closed. Once a channel is closed, any attempt to invoke an I/O operation upon it will cause a ClosedChannelException to be thrown. Whether or not a channel is open may be tested by invoking its isOpen method.

Channels are, in general, intended to be safe for multithreaded access as described in the specifications of the interfaces and classes that extend and implement this interface.

Public Method Summary

abstract void	close() Closes this channel.
abstract boolean	isOpen() Tells whether or not this channel is open.

Inherited Method Summary

From interface java.io.Closeable

abstract void

close() Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Public Methods

public abstract void close ()

Closes this channel.

After a channel is closed, any further attempt to invoke I/O operations upon it will cause a ClosedChannelException to be thrown.

If this channel is already closed then invoking this method has no effect.

This method may be invoked at any time. If some other thread has already invoked it, however, then another invocation will block until the first invocation is complete, after which it will return without effect.

Throws

IOException	If an I/O error occurs

public abstract boolean isOpen ()

Tells whether or not this channel is open.

Returns

• true if, and only if, this channel is open