OpenJDK 1.23 · java.nio.channels.ServerSocketChannel

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

Access	Constructor and Description
protected	ServerSocketChannel(SelectorProvider The provider that created this channel provider) Initializes a new instance of this class.

Method Summary

Modifier and Type	Method and Description
public abstract SocketChannel	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 accept() Accepts a connection made to this channel's socket.
public final ServerSocketChannel	Returns: This channel bind(SocketAddress The local address to bind the socket, or `null` to bind to an automatically assigned socket address local) Implements java.nio.channels.NetworkChannel.bind. Binds the channel's socket to a local address and configures the socket to listen for connections.
public abstract ServerSocketChannel	Returns: This channel bind(SocketAddress The address to bind the socket, or `null` to bind to an automatically assigned socket address local, int The maximum number of pending connections backlog) Binds the channel's socket to a local address and configures the socket to listen for connections.
public abstract SocketAddress	Returns: The `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 bound getLocalAddress() Redeclares java.nio.channels.NetworkChannel.getLocalAddress. Returns the socket address that this channel's socket is bound to.
public static ServerSocketChannel	Returns: A new socket channel open() Opens a server-socket channel for an Internet protocol socket.
public static ServerSocketChannel	Returns: A new socket channel open(ProtocolFamily The protocol family family) Opens a server-socket channel.
public abstract <T> ServerSocketChannel	setOption(SocketOption<T> The socket option name, T The value of the socket option. A value of `null` may be a valid value for some socket options. value) Redeclares java.nio.channels.NetworkChannel.setOption. Sets the value of a socket option.
public abstract ServerSocket	Returns: A server socket associated with this channel socket() Retrieves a server socket associated with this channel.
public final int	Returns: The valid-operation set validOps() Implements abstract java.nio.channels.SelectableChannel.validOps. Returns an operation set identifying this channel's supported operations.

Inherited from java.nio.channels.spi.AbstractSelectableChannel:: blockingLock configureBlocking implCloseChannel implCloseSelectableChannel implConfigureBlocking isBlocking isRegistered keyFor provider register

ServerSocketChannel	back to summary
protected ServerSocketChannel(SelectorProvider provider) Initializes a new instance of this class. Parameters provider:SelectorProvider The provider that created this channel

Method Detail

accept back to summary

accept	back to summary
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. If bound to an Internet protocol socket address, this method performs exactly the same security checks as the `accept` method of the `java.net.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")`. Returns:SocketChannel 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 Exceptions IOException: If some other I/O error occurs 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 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")`

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.

If bound to an Internet protocol socket address, this method performs exactly the same security checks as the accept method of the java.net.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").

Returns:SocketChannel

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

Exceptions

IOException:: If some other I/O error occurs
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 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")

bind back to summary

bind	back to summary
public final ServerSocketChannel bind(SocketAddress local) throws IOException Implements java.nio.channels.NetworkChannel.bind. 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);` bind(local, 0); Parameters local:SocketAddress The local address to bind the socket, or `null` to bind to an automatically assigned socket address Returns:ServerSocketChannel This channel Exceptions IOException: If some other I/O error occurs AlreadyBoundException: If the socket is already bound UnsupportedAddressTypeException: If the type of the given address is not supported ClosedChannelException: If the channel is closed SecurityException: If a security manager has been installed and it denies the operation Since 1.7

public final ServerSocketChannel bind(SocketAddress local) throws IOException

Implements java.nio.channels.NetworkChannel.bind.

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:ServerSocketChannel

This channel

Exceptions

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

Since

1.7

bind back to summary

bind	back to summary
public abstract ServerSocketChannel 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. 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. API Note Binding a server socket channel for a Unix Domain socket, creates a file corresponding to the file path in the `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. Implementation Note Each platform enforces an implementation specific, maximum length for the name of a Unix Domain socket. This limitation is enforced when a channel is bound. The maximum length is typically close to and generally not less than 100 bytes. This limitation also applies to automatically bound server socket channels. See the Unix domain networking properties that can be used to select the temporary directory where these sockets are created. Parameters local:SocketAddress The address to bind the socket, or `null` to bind to an automatically assigned socket address backlog:int The maximum number of pending connections Returns:ServerSocketChannel This channel Exceptions IOException: If some other I/O error occurs AlreadyBoundException: If the socket is already bound UnsupportedAddressTypeException: If the type of the given address is not supported ClosedChannelException: If this channel is closed SecurityException: 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")`. Since 1.7

public abstract ServerSocketChannel 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. 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.

API Note

Binding a server socket channel for a Unix Domain socket, creates a file corresponding to the file path in the 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.

Implementation Note

Each platform enforces an implementation specific, maximum length for the name of a Unix Domain socket. This limitation is enforced when a channel is bound. The maximum length is typically close to and generally not less than 100 bytes. This limitation also applies to automatically bound server socket channels. See the Unix domain networking properties that can be used to select the temporary directory where these sockets are created.

Parameters

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

Returns:ServerSocketChannel

This channel

Exceptions

IOException:: If some other I/O error occurs
AlreadyBoundException:: If the socket is already bound
UnsupportedAddressTypeException:: If the type of the given address is not supported
ClosedChannelException:: If this channel is closed
SecurityException:: 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").

Since

1.7

getLocalAddress back to summary

getLocalAddress	back to summary
public abstract SocketAddress getLocalAddress() throws IOException Redeclares java.nio.channels.NetworkChannel.getLocalAddress. Doc from java.nio.channels.NetworkChannel.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 `java.net.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. Returns:SocketAddress The `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 bound Annotations @Override Exceptions IOException: If an I/O error occurs ClosedChannelException: If the channel is closed

public abstract SocketAddress getLocalAddress() throws IOException

Redeclares java.nio.channels.NetworkChannel.getLocalAddress.

Doc from java.nio.channels.NetworkChannel.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 java.net.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.

Returns:SocketAddress

The 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 bound

Annotations

@Override

Exceptions

IOException:: If an I/O error occurs
ClosedChannelException:: If the channel is closed

open back to summary

open	back to summary
public static ServerSocketChannel open() throws IOException Opens a server-socket channel for an Internet protocol socket. The new channel is created by invoking the `openServerSocketChannel` method of the system-wide default `java.nio.channels.spi.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:ServerSocketChannel A new socket channel Exceptions IOException: If an I/O error occurs See Also java.net.preferIPv4Stack system property

public static ServerSocketChannel open() throws IOException

Opens a server-socket channel for an Internet protocol socket.

The new channel is created by invoking the openServerSocketChannel method of the system-wide default java.nio.channels.spi.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:ServerSocketChannel

A new socket channel

Exceptions

IOException:: If an I/O error occurs

See Also

java.net.preferIPv4Stack system property

open back to summary

open	back to summary
public static ServerSocketChannel open(ProtocolFamily family) throws IOException Opens a server-socket channel. The `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 `java.nio.channels.spi.SelectorProvider` object. Parameters family:ProtocolFamily The protocol family Returns:ServerSocketChannel A new socket channel Exceptions IOException: If an I/O error occurs UnsupportedOperationException: 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. Since 15 See Also java.net.preferIPv4Stack system property

public static ServerSocketChannel open(ProtocolFamily family) throws IOException

Opens a server-socket channel. The 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 java.nio.channels.spi.SelectorProvider object.

Parameters

family:ProtocolFamily: The protocol family

Returns:ServerSocketChannel

A new socket channel

Exceptions

IOException:: If an I/O error occurs
UnsupportedOperationException:: 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.

Since

See Also

java.net.preferIPv4Stack system property

setOption back to summary

setOption	back to summary
public abstract <T> ServerSocketChannel setOption(SocketOption<T> name, T value) throws IOException Redeclares java.nio.channels.NetworkChannel.setOption. Doc from java.nio.channels.NetworkChannel.setOption. Sets the value of a socket option. Parameters <T> The type of the socket option value name:SocketOption<T> 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:ServerSocketChannel This channel Exceptions IOException: If an I/O error occurs UnsupportedOperationException: If the socket option is not supported by this channel IllegalArgumentException: If the value is not a valid value for this socket option ClosedChannelException: If this channel is closed Since 1.7

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

Redeclares java.nio.channels.NetworkChannel.setOption.

Doc from java.nio.channels.NetworkChannel.setOption.

Sets the value of a socket option.

Parameters

<T>: The type of the socket option value
name:SocketOption<T>: 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:ServerSocketChannel

This channel

Exceptions

IOException:: If an I/O error occurs
UnsupportedOperationException:: If the socket option is not supported by this channel
IllegalArgumentException:: If the value is not a valid value for this socket option
ClosedChannelException:: If this channel is closed

Since

1.7

socket back to summary

socket	back to summary
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 `java.net.ServerSocket` class. Returns:ServerSocket A server socket associated with this channel Exceptions UnsupportedOperationException: If the channel's socket is not an Internet protocol 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 java.net.ServerSocket class.

Returns:ServerSocket

A server socket associated with this channel

Exceptions

UnsupportedOperationException:: If the channel's socket is not an Internet protocol socket

validOps back to summary

validOps	back to summary
public final int validOps() Implements abstract java.nio.channels.SelectableChannel.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`. Returns:int The valid-operation set

public final int validOps()

Implements abstract java.nio.channels.SelectableChannel.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.

Returns:int: The valid-operation set

public abstract Class ServerSocketChannel

Constructor Summary

Method Summary

Constructor Detail

Method Detail