Socket
open class Socket : Closeable
kotlin.Any | |
↳ | java.net.Socket |
This class implements client sockets (also called just "sockets"). A socket is an endpoint for communication between two machines.
The actual work of the socket is performed by an instance of the SocketImpl
class. An application, by changing the socket factory that creates the socket implementation, can configure itself to create sockets appropriate to the local firewall.
Summary
Public constructors | |
---|---|
Socket() Creates an unconnected socket, with the system-default type of SocketImpl. |
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Creates an unconnected socket, specifying the type of proxy, if any, that should be used regardless of any other settings. |
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Creates a stream socket and connects it to the specified port number on the named host. |
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Socket(address: InetAddress!, port: Int) Creates a stream socket and connects it to the specified port number at the specified IP address. |
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Socket(host: String!, port: Int, localAddr: InetAddress!, localPort: Int) Creates a socket and connects it to the specified remote host on the specified remote port. |
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Socket(address: InetAddress!, port: Int, localAddr: InetAddress!, localPort: Int) Creates a socket and connects it to the specified remote address on the specified remote port. |
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Creates a stream socket and connects it to the specified port number on the named host. |
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Socket(host: InetAddress!, port: Int, stream: Boolean) Creates a socket and connects it to the specified port number at the specified IP address. |
Protected constructors | |
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Socket(impl: SocketImpl!) Creates an unconnected Socket with a user-specified SocketImpl. |
Public methods | |
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open Unit |
bind(bindpoint: SocketAddress!) Binds the socket to a local address. |
open Unit |
close() Closes this socket. |
open Unit |
connect(endpoint: SocketAddress!) Connects this socket to the server. |
open Unit |
connect(endpoint: SocketAddress!, timeout: Int) Connects this socket to the server with a specified timeout value. |
open SocketChannel! |
Returns the unique |
open InetAddress! |
Returns the address to which the socket is connected. |
open InputStream! |
Returns an input stream for this socket. |
open Boolean |
Tests if |
open InetAddress! |
Gets the local address to which the socket is bound. |
open Int |
Returns the local port number to which this socket is bound. |
open SocketAddress! |
Returns the address of the endpoint this socket is bound to. |
open Boolean |
Tests if |
open T |
getOption(name: SocketOption<T>!) Returns the value of a socket option. |
open OutputStream! |
Returns an output stream for this socket. |
open Int |
getPort() Returns the remote port number to which this socket is connected. |
open Int |
Gets the value of the |
open SocketAddress! |
Returns the address of the endpoint this socket is connected to, or |
open Boolean |
Tests if |
open Int |
Get value of the |
open Int |
Returns setting for |
open Int |
Returns setting for |
open Boolean |
Tests if |
open Int |
Gets traffic class or type-of-service in the IP header for packets sent from this Socket |
open Boolean |
isBound() Returns the binding state of the socket. |
open Boolean |
isClosed() Returns the closed state of the socket. |
open Boolean |
Returns the connection state of the socket. |
open Boolean |
Returns whether the read-half of the socket connection is closed. |
open Boolean |
Returns whether the write-half of the socket connection is closed. |
open Unit |
sendUrgentData(data: Int) Send one byte of urgent data on the socket. |
open Unit |
setKeepAlive(on: Boolean) Enable/disable |
open Unit |
setOOBInline(on: Boolean) Enable/disable |
open Socket! |
setOption(name: SocketOption<T>!, value: T) Sets the value of a socket option. |
open Unit |
setPerformancePreferences(connectionTime: Int, latency: Int, bandwidth: Int) Sets performance preferences for this socket. |
open Unit |
setReceiveBufferSize(size: Int) Sets the |
open Unit |
setReuseAddress(on: Boolean) Enable/disable the |
open Unit |
setSendBufferSize(size: Int) Sets the |
open Unit |
setSoLinger(on: Boolean, linger: Int) Enable/disable |
open Unit |
setSoTimeout(timeout: Int) Enable/disable |
open static Unit |
Sets the client socket implementation factory for the application. |
open Unit |
setTcpNoDelay(on: Boolean) Enable/disable |
open Unit |
setTrafficClass(tc: Int) Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket. |
open Unit |
Places the input stream for this socket at "end of stream". |
open Unit |
Disables the output stream for this socket. |
open MutableSet<SocketOption<*>!>! |
Returns a set of the socket options supported by this socket. |
open String |
toString() Converts this socket to a |
Public constructors
Socket
Socket()
Creates an unconnected socket, with the system-default type of SocketImpl.
Socket
Socket(proxy: Proxy!)
Creates an unconnected socket, specifying the type of proxy, if any, that should be used regardless of any other settings.
If there is a security manager, its checkConnect
method is called with the proxy host address and port number as its arguments. This could result in a SecurityException.
Examples:
Socket s = new Socket(Proxy.NO_PROXY);
will create a plain socket ignoring any other proxy configuration.Socket s = new Socket(new Proxy(Proxy.Type.SOCKS, new InetSocketAddress("socks.mydom.com", 1080)));
will create a socket connecting through the specified SOCKS proxy server.
Parameters | |
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proxy |
Proxy!: a Proxy object specifying what kind of proxying should be used. |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if the proxy is of an invalid type or null . |
java.lang.SecurityException |
if a security manager is present and permission to connect to the proxy is denied. |
See Also
Socket
Socket(
host: String!,
port: Int)
Creates a stream socket and connects it to the specified port number on the named host.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
If the application has specified a server socket factory, that factory's createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
Parameters | |
---|---|
host |
String!: the host name, or null for the loopback address. |
port |
Int: the port number. |
Exceptions | |
---|---|
java.net.UnknownHostException |
if the IP address of the host could not be determined. |
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the operation. |
java.lang.IllegalArgumentException |
if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
Socket
Socket(
address: InetAddress!,
port: Int)
Creates a stream socket and connects it to the specified port number at the specified IP address.
If the application has specified a socket factory, that factory's createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
Parameters | |
---|---|
address |
InetAddress!: the IP address. |
port |
Int: the port number. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the operation. |
java.lang.IllegalArgumentException |
if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
java.lang.NullPointerException |
if address is null. |
Socket
Socket(
host: String!,
port: Int,
localAddr: InetAddress!,
localPort: Int)
Creates a socket and connects it to the specified remote host on the specified remote port. The Socket will also bind() to the local address and port supplied.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
A local port number of zero
will let the system pick up a free port in the bind
operation.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
Parameters | |
---|---|
host |
String!: the name of the remote host, or null for the loopback address. |
port |
Int: the remote port |
localAddr |
InetAddress!: the local address the socket is bound to, or null for the anyLocal address. |
localPort |
Int: the local port the socket is bound to, or zero for a system selected free port. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the connection to the destination, or if its checkListen method doesn't allow the bind to the local port. |
java.lang.IllegalArgumentException |
if the port parameter or localPort parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
See Also
Socket
Socket(
address: InetAddress!,
port: Int,
localAddr: InetAddress!,
localPort: Int)
Creates a socket and connects it to the specified remote address on the specified remote port. The Socket will also bind() to the local address and port supplied.
If the specified local address is null
it is the equivalent of specifying the address as the AnyLocal address (see InetAddress.isAnyLocalAddress
()
).
A local port number of zero
will let the system pick up a free port in the bind
operation.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
Parameters | |
---|---|
address |
InetAddress!: the remote address |
port |
Int: the remote port |
localAddr |
InetAddress!: the local address the socket is bound to, or null for the anyLocal address. |
localPort |
Int: the local port the socket is bound to or zero for a system selected free port. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the connection to the destination, or if its checkListen method doesn't allow the bind to the local port. |
java.lang.IllegalArgumentException |
if the port parameter or localPort parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
java.lang.NullPointerException |
if address is null. |
See Also
Socket
Socket(
host: String!,
port: Int,
stream: Boolean)
Deprecated: Use DatagramSocket instead for UDP transport.
Creates a stream socket and connects it to the specified port number on the named host.
If the specified host is null
it is the equivalent of specifying the address as InetAddress.getByName
(null)
. In other words, it is equivalent to specifying an address of the loopback interface.
If the stream argument is true
, this creates a stream socket. If the stream argument is false
, it creates a datagram socket.
If the application has specified a server socket factory, that factory's createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager, its checkConnect
method is called with the host address and port
as its arguments. This could result in a SecurityException.
If a UDP socket is used, TCP/IP related socket options will not apply.
Parameters | |
---|---|
host |
String!: the host name, or null for the loopback address. |
port |
Int: the port number. |
stream |
Boolean: a boolean indicating whether this is a stream socket or a datagram socket. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the operation. |
java.lang.IllegalArgumentException |
if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
Socket
Socket(
host: InetAddress!,
port: Int,
stream: Boolean)
Deprecated: Use DatagramSocket instead for UDP transport.
Creates a socket and connects it to the specified port number at the specified IP address.
If the stream argument is true
, this creates a stream socket. If the stream argument is false
, it creates a datagram socket.
If the application has specified a server socket factory, that factory's createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.
If there is a security manager, its checkConnect
method is called with host.getHostAddress()
and port
as its arguments. This could result in a SecurityException.
If UDP socket is used, TCP/IP related socket options will not apply.
Parameters | |
---|---|
host |
InetAddress!: the IP address. |
port |
Int: the port number. |
stream |
Boolean: if true , create a stream socket; otherwise, create a datagram socket. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the socket. |
java.lang.SecurityException |
if a security manager exists and its checkConnect method doesn't allow the operation. |
java.lang.IllegalArgumentException |
if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive. |
java.lang.NullPointerException |
if host is null. |
Protected constructors
Socket
protected Socket(impl: SocketImpl!)
Creates an unconnected Socket with a user-specified SocketImpl.
Parameters | |
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impl |
SocketImpl!: an instance of a SocketImpl the subclass wishes to use on the Socket. |
Exceptions | |
---|---|
java.lang.SecurityException |
if impl is non-null and a security manager is set and its checkPermission method doesn't allow NetPermission("setSocketImpl") . |
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
Public methods
bind
open fun bind(bindpoint: SocketAddress!): Unit
Binds the socket to a local address.
If the address is null
, then the system will pick up an ephemeral port and a valid local address to bind the socket.
Parameters | |
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bindpoint |
SocketAddress!: the SocketAddress to bind to |
Exceptions | |
---|---|
java.io.IOException |
if the bind operation fails, or if the socket is already bound. |
java.lang.IllegalArgumentException |
if bindpoint is a SocketAddress subclass not supported by this socket |
java.lang.SecurityException |
if a security manager exists and its checkListen method doesn't allow the bind to the local port. |
See Also
close
open fun close(): Unit
Closes this socket.
Any thread currently blocked in an I/O operation upon this socket will throw a SocketException
.
Once a socket has been closed, it is not available for further networking use (i.e. can't be reconnected or rebound). A new socket needs to be created.
Closing this socket will also close the socket's InputStream
and OutputStream
.
If this socket has an associated channel then the channel is closed as well.
Exceptions | |
---|---|
java.lang.Exception |
if this resource cannot be closed |
java.io.IOException |
if an I/O error occurs |
java.io.IOException |
if an I/O error occurs when closing this socket. |
See Also
connect
open fun connect(endpoint: SocketAddress!): Unit
Connects this socket to the server.
Parameters | |
---|---|
endpoint |
SocketAddress!: the SocketAddress |
Exceptions | |
---|---|
java.io.IOException |
if an error occurs during the connection |
java.nio.channels.IllegalBlockingModeException |
if this socket has an associated channel, and the channel is in non-blocking mode |
java.lang.IllegalArgumentException |
if endpoint is null or is a SocketAddress subclass not supported by this socket |
connect
open fun connect(
endpoint: SocketAddress!,
timeout: Int
): Unit
Connects this socket to the server with a specified timeout value. A timeout of zero is interpreted as an infinite timeout. The connection will then block until established or an error occurs.
Parameters | |
---|---|
endpoint |
SocketAddress!: the SocketAddress |
timeout |
Int: the timeout value to be used in milliseconds. |
Exceptions | |
---|---|
java.io.IOException |
if an error occurs during the connection |
java.net.SocketTimeoutException |
if timeout expires before connecting |
java.nio.channels.IllegalBlockingModeException |
if this socket has an associated channel, and the channel is in non-blocking mode |
java.lang.IllegalArgumentException |
if endpoint is null or is a SocketAddress subclass not supported by this socket |
getChannel
open fun getChannel(): SocketChannel!
Returns the unique SocketChannel
object associated with this socket, if any.
A socket will have a channel if, and only if, the channel itself was created via the java.nio.channels.SocketChannel#open or ServerSocketChannel.accept
methods.
Return | |
---|---|
SocketChannel! |
the socket channel associated with this socket, or null if this socket was not created for a channel |
getInetAddress
open fun getInetAddress(): InetAddress!
Returns the address to which the socket is connected.
If the socket was connected prior to being #close, then this method will continue to return the connected address after the socket is closed.
Return | |
---|---|
InetAddress! |
the remote IP address to which this socket is connected, or null if the socket is not connected. |
getInputStream
open fun getInputStream(): InputStream!
Returns an input stream for this socket.
If this socket has an associated channel then the resulting input stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the input stream's read
operations will throw an java.nio.channels.IllegalBlockingModeException
.
Under abnormal conditions the underlying connection may be broken by the remote host or the network software (for example a connection reset in the case of TCP connections). When a broken connection is detected by the network software the following applies to the returned input stream :-
- The network software may discard bytes that are buffered by the socket. Bytes that aren't discarded by the network software can be read using java.io.InputStream#read.
- If there are no bytes buffered on the socket, or all buffered bytes have been consumed by java.io.InputStream#read, then all subsequent calls to java.io.InputStream#read will throw an
IOException
. - If there are no bytes buffered on the socket, and the socket has not been closed using #close, then
available
will return0
.
Closing the returned InputStream
will close the associated socket.
Return | |
---|---|
InputStream! |
an input stream for reading bytes from this socket. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the input stream, the socket is closed, the socket is not connected, or the socket input has been shutdown using shutdownInput() |
getKeepAlive
open fun getKeepAlive(): Boolean
Tests if SO_KEEPALIVE
is enabled.
Return | |
---|---|
Boolean |
a boolean indicating whether or not SO_KEEPALIVE is enabled. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getLocalAddress
open fun getLocalAddress(): InetAddress!
Gets the local address to which the socket is bound.
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, the loopback
address is returned.
Return | |
---|---|
InetAddress! |
the local address to which the socket is bound, the loopback address if denied by the security manager, or the wildcard address if the socket is closed or not bound yet. |
See Also
getLocalPort
open fun getLocalPort(): Int
Returns the local port number to which this socket is bound.
If the socket was bound prior to being #close, then this method will continue to return the local port number after the socket is closed.
Return | |
---|---|
Int |
the local port number to which this socket is bound or -1 if the socket is not bound yet. |
getLocalSocketAddress
open fun getLocalSocketAddress(): SocketAddress!
Returns the address of the endpoint this socket is bound to.
If a socket bound to an endpoint represented by an InetSocketAddress
is #close, then this method will continue to return an InetSocketAddress
after the socket is closed. In that case the returned InetSocketAddress
's address is the wildcard
address and its port is the local port that it was 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. If the operation is not allowed, a SocketAddress
representing the loopback
address and the local port to which this socket is bound is returned.
Return | |
---|---|
SocketAddress! |
a SocketAddress representing the local endpoint of this socket, or a SocketAddress representing the loopback address if denied by the security manager, or null if the socket is not bound yet. |
getOOBInline
open fun getOOBInline(): Boolean
Tests if SO_OOBINLINE
is enabled.
Return | |
---|---|
Boolean |
a boolean indicating whether or not SO_OOBINLINE is enabled. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getOption
open fun <T : Any!> getOption(name: SocketOption<T>!): T
Returns the value of a socket option.
Parameters | |
---|---|
<T> |
The type of the socket option value |
name |
SocketOption<T>!: The socket option |
Return | |
---|---|
T |
The value of the socket option. |
Exceptions | |
---|---|
java.lang.UnsupportedOperationException |
if the socket does not support the option. |
java.io.IOException |
if an I/O error occurs, or if the socket is closed. |
java.lang.NullPointerException |
if name is null |
java.lang.SecurityException |
if a security manager is set and if the socket option requires a security permission and if the caller does not have the required permission. StandardSocketOptions do not require any security permission. |
getOutputStream
open fun getOutputStream(): OutputStream!
Returns an output stream for this socket.
If this socket has an associated channel then the resulting output stream delegates all of its operations to the channel. If the channel is in non-blocking mode then the output stream's write
operations will throw an .
Closing the returned OutputStream
will close the associated socket.
Return | |
---|---|
OutputStream! |
an output stream for writing bytes to this socket. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when creating the output stream or if the socket is not connected. |
getPort
open fun getPort(): Int
Returns the remote port number to which this socket is connected.
If the socket was connected prior to being #close, then this method will continue to return the connected port number after the socket is closed.
Return | |
---|---|
Int |
the remote port number to which this socket is connected, or 0 if the socket is not connected yet. |
getReceiveBufferSize
open fun getReceiveBufferSize(): Int
Gets the value of the SO_RCVBUF
option for this Socket
, that is the buffer size used by the platform for input on this Socket
.
Return | |
---|---|
Int |
the value of the SO_RCVBUF option for this Socket . |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getRemoteSocketAddress
open fun getRemoteSocketAddress(): SocketAddress!
Returns the address of the endpoint this socket is connected to, or null
if it is unconnected.
If the socket was connected prior to being #close, then this method will continue to return the connected address after the socket is closed.
Return | |
---|---|
SocketAddress! |
a SocketAddress representing the remote endpoint of this socket, or null if it is not connected yet. |
getReuseAddress
open fun getReuseAddress(): Boolean
Tests if SO_REUSEADDR
is enabled.
Return | |
---|---|
Boolean |
a boolean indicating whether or not SO_REUSEADDR is enabled. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getSendBufferSize
open fun getSendBufferSize(): Int
Get value of the SO_SNDBUF
option for this Socket
, that is the buffer size used by the platform for output on this Socket
.
Return | |
---|---|
Int |
the value of the SO_SNDBUF option for this Socket . |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getSoLinger
open fun getSoLinger(): Int
Returns setting for SO_LINGER
. -1 returns implies that the option is disabled. The setting only affects socket close.
Return | |
---|---|
Int |
the setting for SO_LINGER . |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getSoTimeout
open fun getSoTimeout(): Int
Returns setting for SO_TIMEOUT
. 0 returns implies that the option is disabled (i.e., timeout of infinity).
Return | |
---|---|
Int |
the setting for SO_TIMEOUT |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getTcpNoDelay
open fun getTcpNoDelay(): Boolean
Tests if TCP_NODELAY
is enabled.
Return | |
---|---|
Boolean |
a boolean indicating whether or not TCP_NODELAY is enabled. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
getTrafficClass
open fun getTrafficClass(): Int
Gets traffic class or type-of-service in the IP header for packets sent from this Socket
As the underlying network implementation may ignore the traffic class or type-of-service set using setTrafficClass(int)
this method may return a different value than was previously set using the setTrafficClass(int)
method on this Socket.
Return | |
---|---|
Int |
the traffic class or type-of-service already set |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error obtaining the traffic class or type-of-service value. |
isBound
open fun isBound(): Boolean
Returns the binding state of the socket.
Note: Closing a socket doesn't clear its binding state, which means this method will return true
for a closed socket (see isClosed()
) if it was successfuly bound prior to being closed.
Return | |
---|---|
Boolean |
true if the socket was successfuly bound to an address |
See Also
isClosed
open fun isClosed(): Boolean
Returns the closed state of the socket.
Return | |
---|---|
Boolean |
true if the socket has been closed |
See Also
isConnected
open fun isConnected(): Boolean
Returns the connection state of the socket.
Note: Closing a socket doesn't clear its connection state, which means this method will return true
for a closed socket (see isClosed()
) if it was successfuly connected prior to being closed.
Return | |
---|---|
Boolean |
true if the socket was successfuly connected to a server |
isInputShutdown
open fun isInputShutdown(): Boolean
Returns whether the read-half of the socket connection is closed.
Return | |
---|---|
Boolean |
true if the input of the socket has been shutdown |
See Also
isOutputShutdown
open fun isOutputShutdown(): Boolean
Returns whether the write-half of the socket connection is closed.
Return | |
---|---|
Boolean |
true if the output of the socket has been shutdown |
See Also
sendUrgentData
open fun sendUrgentData(data: Int): Unit
Send one byte of urgent data on the socket. The byte to be sent is the lowest eight bits of the data parameter. The urgent byte is sent after any preceding writes to the socket OutputStream and before any future writes to the OutputStream.
Parameters | |
---|---|
data |
Int: The byte of data to send |
Exceptions | |
---|---|
java.io.IOException |
if there is an error sending the data. |
setKeepAlive
open fun setKeepAlive(on: Boolean): Unit
Enable/disable SO_KEEPALIVE
.
Parameters | |
---|---|
on |
Boolean: whether or not to have socket keep alive turned on. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
setOOBInline
open fun setOOBInline(on: Boolean): Unit
Enable/disable SO_OOBINLINE
(receipt of TCP urgent data) By default, this option is disabled and TCP urgent data received on a socket is silently discarded. If the user wishes to receive urgent data, then this option must be enabled. When enabled, urgent data is received inline with normal data.
Note, only limited support is provided for handling incoming urgent data. In particular, no notification of incoming urgent data is provided and there is no capability to distinguish between normal data and urgent data unless provided by a higher level protocol.
Parameters | |
---|---|
on |
Boolean: true to enable SO_OOBINLINE , false to disable. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
setOption
open fun <T : Any!> setOption(
name: SocketOption<T>!,
value: T
): Socket!
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 valid for some options. |
Return | |
---|---|
Socket! |
this Socket |
Exceptions | |
---|---|
java.lang.UnsupportedOperationException |
if the socket does not support the option. |
java.lang.IllegalArgumentException |
if the value is not valid for the option. |
java.io.IOException |
if an I/O error occurs, or if the socket is closed. |
java.lang.NullPointerException |
if name is null |
java.lang.SecurityException |
if a security manager is set and if the socket option requires a security permission and if the caller does not have the required permission. StandardSocketOptions do not require any security permission. |
setPerformancePreferences
open fun setPerformancePreferences(
connectionTime: Int,
latency: Int,
bandwidth: Int
): Unit
Sets performance preferences for this socket.
Sockets use the TCP/IP protocol by default. Some implementations may offer alternative protocols which have different performance characteristics than TCP/IP. This method allows the application to express its own preferences as to how these tradeoffs should be made when the implementation chooses from the available protocols.
Performance preferences are described by three integers whose values indicate the relative importance of short connection time, low latency, and high bandwidth. The absolute values of the integers are irrelevant; in order to choose a protocol the values are simply compared, with larger values indicating stronger preferences. Negative values represent a lower priority than positive values. If the application prefers short connection time over both low latency and high bandwidth, for example, then it could invoke this method with the values (1, 0, 0)
. If the application prefers high bandwidth above low latency, and low latency above short connection time, then it could invoke this method with the values (0, 1, 2)
.
Invoking this method after this socket has been connected will have no effect.
Parameters | |
---|---|
connectionTime |
Int: An int expressing the relative importance of a short connection time |
latency |
Int: An int expressing the relative importance of low latency |
bandwidth |
Int: An int expressing the relative importance of high bandwidth |
setReceiveBufferSize
open fun setReceiveBufferSize(size: Int): Unit
Sets the SO_RCVBUF
option to the specified value for this Socket
. The SO_RCVBUF
option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.
Increasing the receive buffer size can increase the performance of network I/O for high-volume connection, while decreasing it can help reduce the backlog of incoming data.
Because SO_RCVBUF
is a hint, applications that want to verify what size the buffers were set to should call getReceiveBufferSize()
.
The value of SO_RCVBUF
is also used to set the TCP receive window that is advertized to the remote peer. Generally, the window size can be modified at any time when a socket is connected. However, if a receive window larger than 64K is required then this must be requested before the socket is connected to the remote peer. There are two cases to be aware of:
- For sockets accepted from a ServerSocket, this must be done by calling
ServerSocket#setReceiveBufferSize(int)
before the ServerSocket is bound to a local address. - For client sockets, setReceiveBufferSize() must be called before connecting the socket to its remote peer.
Parameters | |
---|---|
size |
Int: the size to which to set the receive buffer size. This value must be greater than 0. |
Exceptions | |
---|---|
java.lang.IllegalArgumentException |
if the value is 0 or is negative. |
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
setReuseAddress
open fun setReuseAddress(on: Boolean): Unit
Enable/disable the SO_REUSEADDR
socket option.
When a TCP connection is closed the connection may remain in a timeout state for a period of time after the connection is closed (typically known as the TIME_WAIT
state or 2MSL
wait state). For applications using a well known socket address or port it may not be possible to bind a socket to the required SocketAddress
if there is a connection in the timeout state involving the socket address or port.
Enabling SO_REUSEADDR
prior to binding the socket using bind(java.net.SocketAddress)
allows the socket to be bound even though a previous connection is in a timeout state.
When a Socket
is created the initial setting of SO_REUSEADDR
is disabled.
The behaviour when SO_REUSEADDR
is enabled or disabled after a socket is bound (See isBound()
) is not defined.
Parameters | |
---|---|
on |
Boolean: whether to enable or disable the socket option |
Exceptions | |
---|---|
java.net.SocketException |
if an error occurs enabling or disabling the SO_REUSEADDR socket option, or the socket is closed. |
setSendBufferSize
open fun setSendBufferSize(size: Int): Unit
Sets the SO_SNDBUF
option to the specified value for this Socket
. The SO_SNDBUF
option is used by the platform's networking code as a hint for the size to set the underlying network I/O buffers.
Because SO_SNDBUF
is a hint, applications that want to verify what size the buffers were set to should call getSendBufferSize()
.
Parameters | |
---|---|
size |
Int: the size to which to set the send buffer size. This value must be greater than 0. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
java.lang.IllegalArgumentException |
if the value is 0 or is negative. |
See Also
setSoLinger
open fun setSoLinger(
on: Boolean,
linger: Int
): Unit
Enable/disable SO_LINGER
with the specified linger time in seconds. The maximum timeout value is platform specific. The setting only affects socket close.
Parameters | |
---|---|
on |
Boolean: whether or not to linger on. |
linger |
Int: how long to linger for, if on is true. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
java.lang.IllegalArgumentException |
if the linger value is negative. |
See Also
setSoTimeout
open fun setSoTimeout(timeout: Int): Unit
Enable/disable SO_TIMEOUT
with the specified timeout, in milliseconds. With this option set to a non-zero timeout, a read() call on the InputStream associated with this Socket will block for only this amount of time. If the timeout expires, a java.net.SocketTimeoutException is raised, though the Socket is still valid. The option must be enabled prior to entering the blocking operation to have effect. The timeout must be > 0
. A timeout of zero is interpreted as an infinite timeout.
Parameters | |
---|---|
timeout |
Int: the specified timeout, in milliseconds. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
setSocketImplFactory
open static fun setSocketImplFactory(fac: SocketImplFactory!): Unit
Sets the client socket implementation factory for the application. The factory can be specified only once.
When an application creates a new client socket, the socket implementation factory's createSocketImpl
method is called to create the actual socket implementation.
Passing null
to the method is a no-op unless the factory was already set.
If there is a security manager, this method first calls the security manager's checkSetFactory
method to ensure the operation is allowed. This could result in a SecurityException.
Parameters | |
---|---|
fac |
SocketImplFactory!: the desired factory. |
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when setting the socket factory. |
java.net.SocketException |
if the factory is already defined. |
java.lang.SecurityException |
if a security manager exists and its checkSetFactory method doesn't allow the operation. |
setTcpNoDelay
open fun setTcpNoDelay(on: Boolean): Unit
Enable/disable TCP_NODELAY
(disable/enable Nagle's algorithm).
Parameters | |
---|---|
on |
Boolean: true to enable TCP_NODELAY, false to disable. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error in the underlying protocol, such as a TCP error. |
See Also
setTrafficClass
open fun setTrafficClass(tc: Int): Unit
Sets traffic class or type-of-service octet in the IP header for packets sent from this Socket. As the underlying network implementation may ignore this value applications should consider it a hint.
The tc must be in the range 0 <= tc <= 255
or an IllegalArgumentException will be thrown.
Notes:
For Internet Protocol v4 the value consists of an integer
, the least significant 8 bits of which represent the value of the TOS octet in IP packets sent by the socket. RFC 1349 defines the TOS values as follows:
IPTOS_LOWCOST (0x02)
IPTOS_RELIABILITY (0x04)
IPTOS_THROUGHPUT (0x08)
IPTOS_LOWDELAY (0x10)
Setting bits in the precedence field may result in a SocketException indicating that the operation is not permitted.
As RFC 1122 section 4.2.4.2 indicates, a compliant TCP implementation should, but is not required to, let application change the TOS field during the lifetime of a connection. So whether the type-of-service field can be changed after the TCP connection has been established depends on the implementation in the underlying platform. Applications should not assume that they can change the TOS field after the connection.
For Internet Protocol v6 tc
is the value that would be placed into the sin6_flowinfo field of the IP header.
Parameters | |
---|---|
tc |
Int: an int value for the bitset. |
Exceptions | |
---|---|
java.net.SocketException |
if there is an error setting the traffic class or type-of-service |
shutdownInput
open fun shutdownInput(): Unit
Places the input stream for this socket at "end of stream". Any data sent to the input stream side of the socket is acknowledged and then silently discarded.
If you read from a socket input stream after invoking this method on the socket, the stream's available
method will return 0, and its read
methods will return -1
(end of stream).
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when shutting down this socket. |
shutdownOutput
open fun shutdownOutput(): Unit
Disables the output stream for this socket. For a TCP socket, any previously written data will be sent followed by TCP's normal connection termination sequence. If you write to a socket output stream after invoking shutdownOutput() on the socket, the stream will throw an IOException.
Exceptions | |
---|---|
java.io.IOException |
if an I/O error occurs when shutting down this socket. |
supportedOptions
open fun supportedOptions(): MutableSet<SocketOption<*>!>!
Returns a set of the socket options supported by this socket. This method will continue to return the set of options even after the socket has been closed.
Return | |
---|---|
MutableSet<SocketOption<*>!>! |
A set of the socket options supported by this socket. This set may be empty if the socket's SocketImpl cannot be created. |
toString
open fun toString(): String
Converts this socket to a String
.
Return | |
---|---|
String |
a string representation of this socket. |