Added in API level 26

Summary: Protected Ctors | Methods | Inherited Methods

AsynchronousServerSocketChannel

public abstract class AsynchronousServerSocketChannel
extends Object implements AsynchronousChannel, NetworkChannel

java.lang.Object
↳	java.nio.channels.AsynchronousServerSocketChannel

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) {
          ...
      }
  });

Summary

Protected constructors
`AsynchronousServerSocketChannel(AsynchronousChannelProvider provider)` Initializes a new instance of this class.

Public methods
`abstract Future<AsynchronousSocketChannel>`	`accept()` Accepts a connection.
`abstract <A> void`	`accept(A attachment, CompletionHandler<AsynchronousSocketChannel, ? super A> handler)` Accepts a connection.
`abstract AsynchronousServerSocketChannel`	`bind(SocketAddress local, int backlog)` Binds the channel's socket to a local address and configures the socket to listen for connections.
`final AsynchronousServerSocketChannel`	`bind(SocketAddress local)` 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. If there is a security manager set, its `checkConnect` method is called with the local address and `-1` as its arguments to see if the operation is allowed.
`static AsynchronousServerSocketChannel`	`open(AsynchronousChannelGroup group)` Opens an asynchronous server-socket channel.
`static AsynchronousServerSocketChannel`	`open()` 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.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the 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(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.
`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()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.nio.channels.AsynchronousChannel


      close()

Closes this channel.

From interface


        
          java.nio.channels.NetworkChannel

`abstract NetworkChannel`	`bind(SocketAddress local)` Binds the channel's socket to a local address.
`abstract SocketAddress`	`getLocalAddress()` Returns the socket address that this channel's socket is bound to.
`abstract <T> T`	`getOption(SocketOption<T> name)` Returns the value of a socket option.
`abstract <T> NetworkChannel`	`setOption(SocketOption<T> name, T value)` Sets the value of a socket option.
`abstract Set<SocketOption<?>>`	`supportedOptions()` Returns a set of the socket options supported by this channel.

From interface


        
          java.nio.channels.Channel

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

From interface


        
          java.io.Closeable


      close()

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

From interface


        
          java.lang.AutoCloseable


      close()

Closes this resource, relinquishing any underlying resources.

Protected constructors

AsynchronousServerSocketChannel

Added in API level 26

protected AsynchronousServerSocketChannel (AsynchronousChannelProvider provider)

Initializes a new instance of this class.

Parameters
`provider`	`AsynchronousChannelProvider`: The provider that created this channel

Public methods

accept

Added in API level 26

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(java.lang.Object, java.nio.channels.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
`Future<AsynchronousSocketChannel>`	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

accept

Added in API level 26

public abstract 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).

If a security manager has been installed then it verifies that the address and port number of the connection's remote endpoint are permitted by the security manager's checkAccept method. The permission check is performed with privileges that are restricted by the calling context of this method. If the permission check fails then the connection is closed and the operation completes with a SecurityException.

Parameters
`attachment`	`A`: The object to attach to the I/O operation; can be `null`
`handler`	`CompletionHandler`: 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

bind

Added in API level 26

public abstract AsynchronousServerSocketChannel bind (SocketAddress local, 
                int backlog)

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 altogther. If the backlog parameter has the value 0, or a negative value, then an implementation specific default is used.

Parameters
`local`	`SocketAddress`: The local address to bind the socket, or `null` to bind to an automatically assigned socket address
`backlog`	`int`: The maximum number of pending connections

Returns
`AsynchronousServerSocketChannel`	This channel

Throws
`AlreadyBoundException`	If the socket is already bound
`UnsupportedAddressTypeException`	If the type of the given address is not supported
`SecurityException`	If a security manager has been installed and its `checkListen` method denies the operation
`ClosedChannelException`	If the channel is closed
`IOException`	If some other I/O error occurs

bind

Added in API level 26

public final AsynchronousServerSocketChannel bind (SocketAddress local)

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);

Parameters
`local`	`SocketAddress`: The local address to bind the socket, or `null` to bind to an automatically assigned socket address

Returns
`AsynchronousServerSocketChannel`	This channel

Throws
`AlreadyBoundException`
`UnsupportedAddressTypeException`
`SecurityException`
`ClosedChannelException`
`IOException`

getLocalAddress

Added in API level 26

public abstract SocketAddress getLocalAddress ()

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.

If there is a security manager set, its checkConnect method is called with the local address and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, a SocketAddress representing the loopback address and the local port of the channel's socket is returned.

Returns
`SocketAddress`	The `SocketAddress` that the socket is bound to, or the `SocketAddress` representing the loopback address if denied by the security manager, or `null` if the channel's socket is not bound

Throws
`ClosedChannelException`
`IOException`

open

Added in API level 26

public static AsynchronousServerSocketChannel open (AsynchronousChannelGroup group)

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`	`AsynchronousChannelGroup`: The group to which the newly constructed channel should be bound, or `null` for the default group

Returns
`AsynchronousServerSocketChannel`	A new asynchronous server socket channel

Throws
`ShutdownChannelGroupException`	If the channel group is shutdown
`IOException`	If an I/O error occurs

open

Added in API level 26

public static AsynchronousServerSocketChannel open ()

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
`AsynchronousServerSocketChannel`	A new asynchronous server socket channel

Throws
`IOException`	If an I/O error occurs

provider

Added in API level 26

public final AsynchronousChannelProvider provider ()

Returns the provider that created this channel.

Returns
`AsynchronousChannelProvider`	The provider that created this channel

setOption

Added in API level 26

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

Sets the value of a socket option.

Parameters
`name`	`SocketOption`: The socket option
`value`	`T`: The value of the socket option. A value of `null` may be a valid value for some socket options.

Returns
`AsynchronousServerSocketChannel`	This channel

Throws
`IllegalArgumentException`
`ClosedChannelException`
`IOException`