Java in a Nutshell, 5th Edition

Name

SocketChannel

Synopsis

This class is a channel for communicating over a java.net.Socket. It implements ReadableByteChannel and WriteableByteChannel as well as GatheringByteChannel and ScatteringByteChannel. It is a subclass of SelectableChannel and can be used with a Selector.

Create a new SocketChannel with one of the static open( ) methods. The no-argument version of open( ) creates a new SocketChannel but does not connect it to a remote host. The other version of open( ) opens a new channel and connects it to the specified java.net.SocketAddress. If you create an unconnected socket, you can explictly connect it with the connect( ) method. The main reason to open the channel and connect to the remote host in separate steps is if you want to do a nonblocking connect. To do this, first put the channel into nonblocking mode with the inherited configureBlocking( ) method. Then, call connect( ) : it will return immediately, without waiting for the connection to be established. Then register the channel with a Selector specifying that you are interested in SelectionKey.OP_CONNECT operations. When you are notified that your channel is ready to connect (see Selector and SelectionKey for details) simply call the nonblocking finishConnect( ) method to complete the connection. isConnected( ) returns true once a connection is established, and false otherwise. isConnectionPending( ) returns true if connect( ) has been called in blocking mode and has not yet returned, or if connect( ) has ...