java.nio.channels
Class ServerSocketChannel

java.lang.Object
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  +--java.nio.channels.spi.AbstractInterruptibleChannel
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        +--java.nio.channels.SelectableChannel
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              +--java.nio.channels.spi.AbstractSelectableChannel
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                    +--java.nio.channels.ServerSocketChannel

All Implemented Interfaces:

Channel, InterruptibleChannel

public abstract class ServerSocketChannel

extends AbstractSelectableChannel

A selectable channel for stream-oriented listening sockets.

Server-socket channels are not a complete abstraction of listening network sockets. Binding and the manipulation of socket options must be done through an associated ServerSocket object obtained by invoking the socket method. It is not possible to create a channel for an arbitrary, pre-existing server socket, nor is it possible to specify the SocketImpl object to be used by a server socket associated with a server-socket channel.

A server-socket channel is created by invoking the open method of this class. A newly-created server-socket channel is open but not yet bound. An attempt to invoke the accept method of an unbound server-socket channel will cause a NotYetBoundException to be thrown. A server-socket channel can be bound by invoking one of the bind methods of an associated server socket.

Server-socket channels are safe for use by multiple concurrent threads.

Since:

1.4

Constructor Summary

protected

ServerSocketChannel(SelectorProvider provider) Initializes a new instance of this class.

Method Summary

abstract SocketChannel	accept() Accepts a connection made to this channel's socket.
static ServerSocketChannel	open() Opens a server-socket channel.
abstract ServerSocket	socket() Retrieves a server socket associated with this channel.
int	validOps() Returns an operation set identifying this channel's supported operations.

Methods inherited from class java.nio.channels.spi.AbstractSelectableChannel

blockingLock, configureBlocking, implCloseChannel, implCloseSelectableChannel, implConfigureBlocking, isBlocking, isRegistered, keyFor, provider, register

Methods inherited from class java.nio.channels.SelectableChannel

register

Methods inherited from class java.nio.channels.spi.AbstractInterruptibleChannel

begin, close, end, isOpen

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.nio.channels.Channel

close, isOpen

Constructor Detail

ServerSocketChannel

protected ServerSocketChannel(SelectorProvider provider)

Initializes a new instance of this class.

Method Detail

open

public static ServerSocketChannel open()
                                throws IOException

Opens a server-socket channel.

The new channel is created by invoking the openServerSocketChannel method of the system-wide default SelectorProvider object.

The new channel's socket is initially unbound; it must be bound to a specific address via one of its socket's bind methods before connections can be accepted.

Returns:

A new socket channel

Throws:

IOException - If an I/O error occurs

validOps

public final int validOps()

Returns an operation set identifying this channel's supported operations.

Server-socket channels only support the accepting of new connections, so this method returns SelectionKey.OP_ACCEPT.

Specified by:

validOps in class SelectableChannel

Returns:

The valid-operation set

socket

public abstract ServerSocket socket()

Retrieves a server socket associated with this channel.

The returned object will not declare any public methods that are not declared in the ServerSocket class.

Returns:

A server socket associated with this channel

accept

public abstract SocketChannel accept()
                              throws IOException

Accepts a connection made to this channel's socket.

If this channel is in non-blocking mode then this method will immediately return null if there are no pending connections. Otherwise it will block indefinitely until a new connection is available or an I/O error occurs.

The socket channel returned by this method, if any, will be in blocking mode regardless of the blocking mode of this channel.

This method performs exactly the same security checks as the accept method of the ServerSocket class. That is, if a security manager has been installed then for each new connection this method verifies that the address and port number of the connection's remote endpoint are permitted by the security manager's checkAccept method.

Returns:

The socket channel for the new connection, or null if this channel is in non-blocking mode and no connection is available to be accepted

Throws:

ClosedChannelException - If this channel is closed

AsynchronousCloseException - If another thread closes this channel while the accept operation is in progress

ClosedByInterruptException - If another thread interrupts the current thread while the accept operation is in progress, thereby closing the channel and setting the current thread's interrupt status

NotYetBoundException - If this channel's socket has not yet been bound

SecurityException - If a security manager has been installed and it does not permit access to the remote endpoint of the new connection

IOException - If some other I/O error occurs