Closeable
, AutoCloseable
, Channel
, InterruptibleChannel
, NetworkChannel
public abstract class ServerSocketChannel extends AbstractSelectableChannel implements NetworkChannel
A server-socket channel is created by invoking one of the open
methods of this class. The no-arg open
method opens a server-socket channel for an Internet protocol socket. The open(ProtocolFamily)
method is used to open a server-socket channel for a socket of a specified protocol family. It is not possible to create a channel for an arbitrary, pre-existing socket. 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 defined by this class.
Socket options are configured using the setOption
method. Server-socket channels for Internet protocol sockets support the following options:
Option Name Description SO_RCVBUF
The size of the socket receive buffer SO_REUSEADDR
Re-use address
Server-socket channels for Unix domain sockets support:
Option Name Description SO_RCVBUF
The size of the socket receive buffer
Additional (implementation specific) options may also be supported.
Server-socket channels are safe for use by multiple concurrent threads.
Modifier | Constructor | Description |
---|---|---|
protected |
Initializes a new instance of this class. |
Modifier and Type | Method | Description |
---|---|---|
abstract SocketChannel |
accept() |
Accepts a connection made to this channel's socket. |
final ServerSocketChannel |
bind |
Binds the channel's socket to a local address and configures the socket to listen for connections. |
abstract ServerSocketChannel |
bind |
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 ServerSocketChannel |
open() |
Opens a server-socket channel for an Internet protocol socket. |
static ServerSocketChannel |
open |
Opens a server-socket channel. |
abstract <T> ServerSocketChannel |
setOption |
Sets the value of a socket option. |
abstract ServerSocket |
socket() |
Retrieves a server socket associated with this channel. |
final int |
validOps() |
Returns an operation set identifying this channel's supported operations. |
blockingLock, configureBlocking, implCloseChannel, implCloseSelectableChannel, implConfigureBlocking, isBlocking, isRegistered, keyFor, provider, register
register
begin, close, end, isOpen
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
getOption, supportedOptions
protected ServerSocketChannel(SelectorProvider provider)
provider
- The provider that created this channelpublic static ServerSocketChannel open() throws IOException
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.
IOException
- If an I/O error occurspublic static ServerSocketChannel open(ProtocolFamily family) throws IOException
family
parameter specifies the protocol family
of the channel's socket. The new channel is created by invoking the openServerSocketChannel(ProtocolFamily)
method of the system-wide default SelectorProvider
object.
family
- The protocol familyUnsupportedOperationException
- If the specified protocol family is not supported. For example, suppose the parameter is specified as StandardProtocolFamily.INET6
but IPv6 is not enabled on the platform.IOException
- If an I/O error occurspublic final int validOps()
Server-socket channels only support the accepting of new connections, so this method returns SelectionKey.OP_ACCEPT
.
validOps
in class SelectableChannel
public final ServerSocketChannel bind(SocketAddress local) throws IOException
An invocation of this method is equivalent to the following:
bind(local, 0);
bind
in interface NetworkChannel
local
- The local address to bind the socket, or null
to bind to an automatically assigned socket addressAlreadyBoundException
- If the socket is already boundUnsupportedAddressTypeException
- If the type of the given address is not supportedClosedChannelException
- If the channel is closedIOException
- If some other I/O error occursSecurityException
- If a security manager has been installed and it denies the operationpublic abstract ServerSocketChannel bind(SocketAddress local, int backlog) throws IOException
This method is used to establish an association between the socket and a local address. For Internet protocol sockets, once an association is established then the socket remains bound until the 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.
UnixDomainSocketAddress
. This file persists after the channel is closed, and must be removed before another socket can bind to the same name. Binding to a null
address causes the socket to be automatically bound to some unique file in a system temporary location. The associated socket file also persists after the channel is closed. Its name can be obtained from the channel's local socket address.local
- The address to bind the socket, or null
to bind to an automatically assigned socket addressbacklog
- The maximum number of pending connectionsAlreadyBoundException
- If the socket is already boundUnsupportedAddressTypeException
- If the type of the given address is not supportedClosedChannelException
- If this channel is closedIOException
- If some other I/O error occursSecurityException
- If a security manager has been installed and its checkListen
method denies the operation for an Internet protocol socket address, or for a Unix domain socket address if it denies NetPermission
("accessUnixDomainSocket")
.public abstract <T> ServerSocketChannel setOption(SocketOption<T> name, T value) throws IOException
NetworkChannel
setOption
in interface NetworkChannel
T
- The type of the socket option valuename
- The socket optionvalue
- The value of the socket option. A value of null
may be a valid value for some socket options.UnsupportedOperationException
- If the socket option is not supported by this channelIllegalArgumentException
- If the value is not a valid value for this socket optionClosedChannelException
- If this channel is closedIOException
- If an I/O error occurspublic abstract ServerSocket socket()
The returned object will not declare any public methods that are not declared in the ServerSocket
class.
UnsupportedOperationException
- If the channel's socket is not an Internet protocol socketpublic abstract SocketChannel accept() throws IOException
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.
If bound to an Internet protocol socket address, 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. If bound to a Unix Domain socket address, this method checks NetPermission
("accessUnixDomainSocket")
.
null
if this channel is in non-blocking mode and no connection is available to be acceptedClosedChannelException
- If this channel is closedAsynchronousCloseException
- If another thread closes this channel while the accept operation is in progressClosedByInterruptException
- 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 statusNotYetBoundException
- If this channel's socket has not yet been boundSecurityException
- If a security manager has been installed and this channel is bound to an InetSocketAddress
and the security manager denies access to the remote endpoint of the new connection, or if this channel is bound to a UnixDomainSocketAddress
and the security manager denies NetPermission
("accessUnixDomainSocket")
IOException
- If some other I/O error occurspublic abstract SocketAddress getLocalAddress() throws IOException
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.
Where the channel is bound to a Unix Domain socket address, the socket address is a UnixDomainSocketAddress
. If there is a security manager set, its checkPermission
method is called with NetPermission
("accessUnixDomainSocket")
. If the operation is not allowed an unnamed UnixDomainSocketAddress
is returned.
getLocalAddress
in interface NetworkChannel
SocketAddress
that the socket is bound to, or the SocketAddress
representing the loopback address or empty path if denied by the security manager, or null
if the channel's socket is not boundClosedChannelException
- If the channel is closedIOException
- If an I/O error occurs
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/nio/channels/ServerSocketChannel.html