Class AsynchronousServerSocketChannel

java.lang.Object

java.nio.channels.AsynchronousServerSocketChannel

All Implemented Interfaces:: Closeable, AutoCloseable, AsynchronousChannel, Channel, NetworkChannel

public abstract class AsynchronousServerSocketChannel extends Object implements AsynchronousChannel, NetworkChannel

An asynchronous channel for stream-oriented listening sockets.

An asynchronous server-socket channel is created by invoking the open method of this class. A newly-created asynchronous server-socket channel is open but not yet bound. It can be bound to a local address and configured to listen for connections by invoking the bind method. Once bound, the accept method is used to initiate the accepting of connections to the channel's socket. An attempt to invoke the accept method on an unbound channel will cause a NotYetBoundException to be thrown.

Channels of this type are safe for use by multiple concurrent threads though at most one accept operation can be outstanding at any time. If a thread initiates an accept operation before a previous accept operation has completed then an AcceptPendingException will be thrown.

Socket options are configured using the setOption method. Channels of this type support the following options:

Socket options

Option Name Description

SO_RCVBUF The size of the socket receive buffer

SO_REUSEADDR Re-use address

Socket options
Option Name	Description
`SO_RCVBUF`	The size of the socket receive buffer
`SO_REUSEADDR`	Re-use address

Additional (implementation specific) options may also be supported.

Usage Example:

 final AsynchronousServerSocketChannel listener =
     AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(5000));

 listener.accept(null, new CompletionHandler<AsynchronousSocketChannel,Void>() {
     public void completed(AsynchronousSocketChannel ch, Void att) {
         // accept the next connection
         listener.accept(null, this);

         // handle this connection
         handle(ch);
     }
     public void failed(Throwable exc, Void att) {
         ...
     }
 });

Since:: 1.7

Constructor Summary

AsynchronousServerSocketChannel(AsynchronousChannelProvider provider)

Modifier	Constructor	Description
`protected`	Initializes a new instance of this class.

Method Summary

Modifier and Type	Method	Description
`abstract Future<AsynchronousSocketChannel>`	`accept()`	Accepts a connection.
`abstract <A> void`	`accept(A attachment, CompletionHandler<AsynchronousSocketChannel, ? super A> handler)`	Accepts a connection.
`final AsynchronousServerSocketChannel`	`bind(SocketAddress local)`	Binds the channel's socket to a local address and configures the socket to listen for connections.
`abstract AsynchronousServerSocketChannel`	`bind(SocketAddress local, int backlog)`	Binds the channel's socket to a local address and configures the socket to listen for connections.
`abstract SocketAddress`	`getLocalAddress()`	Returns the socket address that this channel's socket is bound to.
`static AsynchronousServerSocketChannel`	`open()`	Opens an asynchronous server-socket channel.
`static AsynchronousServerSocketChannel`	`open(AsynchronousChannelGroup group)`	Opens an asynchronous server-socket channel.
`final AsynchronousChannelProvider`	`provider()`	Returns the provider that created this channel.
`abstract <T> AsynchronousServerSocketChannel`	`setOption(SocketOption<T> name, T value)`	Sets the value of a socket option.

Methods declared in class Object

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

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Methods declared in interface AsynchronousChannel

close

Modifier and Type	Method	Description
`void`	`close()`	Closes this channel.

Methods declared in interface Channel

isOpen

Modifier and Type	Method	Description
`boolean`	`isOpen()`	Tells whether or not this channel is open.

Methods declared in interface NetworkChannel

getOption, supportedOptions

Modifier and Type	Method	Description
`<T> T`	`getOption(SocketOption<T> name)`	Returns the value of a socket option.
`Set<SocketOption<?>>`	`supportedOptions()`	Returns a set of the socket options supported by this channel.

Constructor Details

AsynchronousServerSocketChannel

protected AsynchronousServerSocketChannel(AsynchronousChannelProvider provider)

Initializes a new instance of this class.

Parameters:: provider - The provider that created this channel

Method Details

provider

public final AsynchronousChannelProvider provider()

Returns the provider that created this channel.

Returns:: The provider that created this channel

open

public static AsynchronousServerSocketChannel open(AsynchronousChannelGroup group) throws IOException

Opens an asynchronous server-socket channel.

The new channel is created by invoking the openAsynchronousServerSocketChannel method on the AsynchronousChannelProvider object that created the given group. If the group parameter is null then the resulting channel is created by the system-wide default provider, and bound to the default group.

Parameters:: group - The group to which the newly constructed channel should be bound, or null for the default group
Returns:: A new asynchronous server socket channel
Throws:: ShutdownChannelGroupException - If the channel group is shutdown; IOException - If an I/O error occurs

open

public static AsynchronousServerSocketChannel open() throws IOException

Opens an asynchronous server-socket channel.

This method returns an asynchronous server socket channel that is bound to the default group. This method is equivalent to evaluating the expression:

    open((AsynchronousChannelGroup)null);

Returns:: A new asynchronous server socket channel
Throws:: IOException - If an I/O error occurs

bind

public final AsynchronousServerSocketChannel bind(SocketAddress local) throws IOException

Binds the channel's socket to a local address and configures the socket to listen for connections.

An invocation of this method is equivalent to the following:

    bind(local, 0);

Specified by:

bind in interface NetworkChannel

Parameters:

local - The local address to bind the socket, or null to bind to an automatically assigned socket address

Returns:

This channel

Throws:

AlreadyBoundException - If the socket is already bound

UnsupportedAddressTypeException - If the type of the given address is not supported

ClosedChannelException - If the channel is closed

IOException - If some other I/O error occurs

See Also:

bind

public abstract AsynchronousServerSocketChannel bind(SocketAddress local, int backlog) throws IOException

Binds the channel's socket to a local address and configures the socket to listen for connections.

This method is used to establish an association between the socket and a local address. Once an association is established then the socket remains bound until the associated channel is closed.

The backlog parameter is the maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogether. If the backlog parameter has the value 0, or a negative value, then an implementation specific default is used.

Parameters:: local - The local address to bind the socket, or null to bind to an automatically assigned socket address; backlog - The maximum number of pending connections
Returns:: This channel
Throws:: AlreadyBoundException - If the socket is already bound; UnsupportedAddressTypeException - If the type of the given address is not supported; ClosedChannelException - If the channel is closed; IOException - If some other I/O error occurs

setOption

public abstract <T> AsynchronousServerSocketChannel setOption(SocketOption<T> name, T value) throws IOException

Description copied from interface: NetworkChannel

Sets the value of a socket option.

Specified by:

setOption in interface NetworkChannel

Type Parameters:

T - The type of the socket option value

Parameters:

name - The socket option

value - The value of the socket option. A value of null may be a valid value for some socket options.

Returns:

This channel

Throws:

IllegalArgumentException - If the value is not a valid value for this socket option

ClosedChannelException - If this channel is closed

IOException - If an I/O error occurs

See Also:

accept

public abstract <A> void accept(A attachment, CompletionHandler<AsynchronousSocketChannel, ? super A> handler)

Accepts a connection.

This method initiates an asynchronous operation to accept a connection made to this channel's socket. The handler parameter is a completion handler that is invoked when a connection is accepted (or the operation fails). The result passed to the completion handler is the AsynchronousSocketChannel to the new connection.

When a new connection is accepted then the resulting AsynchronousSocketChannel will be bound to the same AsynchronousChannelGroup as this channel. If the group is shutdown and a connection is accepted, then the connection is closed, and the operation completes with an IOException and cause ShutdownChannelGroupException.

To allow for concurrent handling of new connections, the completion handler is not invoked directly by the initiating thread when a new connection is accepted immediately (see Threading).

Type Parameters:: A - The type of the attachment
Parameters:: attachment - The object to attach to the I/O operation; can be null; handler - The handler for consuming the result
Throws:: AcceptPendingException - If an accept operation is already in progress on this channel; NotYetBoundException - If this channel's socket has not yet been bound; ShutdownChannelGroupException - If the channel group has terminated

accept

public abstract Future<AsynchronousSocketChannel> accept()

Accepts a connection.

This method initiates an asynchronous operation to accept a connection made to this channel's socket. The method behaves in exactly the same manner as the accept(Object, CompletionHandler) method except that instead of specifying a completion handler, this method returns a Future representing the pending result. The Future's get method returns the AsynchronousSocketChannel to the new connection on successful completion.

Returns:: a Future object representing the pending result
Throws:: AcceptPendingException - If an accept operation is already in progress on this channel; NotYetBoundException - If this channel's socket has not yet been bound

getLocalAddress

public abstract SocketAddress getLocalAddress() throws IOException

Returns the socket address that this channel's socket is bound to.

Where the channel is bound to an Internet Protocol socket address then the return value from this method is of type InetSocketAddress.

Specified by:: getLocalAddress in interface NetworkChannel
Returns:: The SocketAddress that the socket is bound to; null if the channel's socket is not bound
Throws:: ClosedChannelException - If the channel is closed; IOException - If an I/O error occurs

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