A Channel is a conduit that tansport data efficiently between byte buffers and the entity on the other end of the channel (usually a file or socket).

Interfaces

• Channel
• InterruptibleChannel: most channels are interruptible
• WritableByteChannel: Channel operate only on byte buffers.
• GetheringByteChannel
• ReadableByteChannel
• ReadableByteChannel

public interface Channel {
public boolean isOpen();
public void close() throws IOException;
}

public interface ReadableByteChannel extends Channel {
public int read(ByteBuffer dst) throws IOException;
}

public interface WritableByteChannel extends Channel {
public int write(ByteBuffer src) throws IOException;
}

public interface ByteChannel
extends ReadableByteChannel, WritableByteChannel{
}

public interface ScatteringByteChannel
extends ReadableByteChannel {
public long read(ByteBuffer[] dsts) throws IOException;
public long read(ByteBuffer[] dsts, int offset, int length) throws IOException;
}

public interface GatheringByteChannel
extends WritableByteChannel {
public long write(ByteBuffer[] srcs) throws IOException;
public long write(ByteBuffer[] scrs, int offset, int length) throws IOException;
}

Scatter/Gather refers to performing a single I/O operate across multiple buffers.

Channels

There are two types of channels:

• file I/O: file
• FileChannel
• stream I/O: socket
• SocketChannel
• ServerSocketChannel
• DatagramChannel

Channels can operate in blocking or nonblocking modes. Only stream-oriented channels, such as sockets and pipes , can be placed in nonblocking mode.

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