DatagramSocketImpl
, SocketImpl
public interface SocketOptions
The methods and constants which specify options in this interface are for implementation only. If you're not subclassing SocketImpl or DatagramSocketImpl, you won't use these directly. There are type-safe methods to get/set each of these options in Socket, ServerSocket, DatagramSocket and MulticastSocket.
Modifier and Type | Field | Description |
---|---|---|
static final int |
IP_MULTICAST_IF |
Set which outgoing interface on which to send multicast packets. |
static final int |
IP_MULTICAST_IF2 |
Same as above. |
static final int |
IP_MULTICAST_LOOP |
This option enables or disables local loopback of multicast datagrams. |
static final int |
IP_TOS |
This option sets the type-of-service or traffic class field in the IP header for a TCP or UDP socket. |
static final int |
SO_BINDADDR |
Fetch the local address binding of a socket (this option cannot be "set" only "gotten", since sockets are bound at creation time, and so the locally bound address cannot be changed). |
static final int |
SO_BROADCAST |
Sets SO_BROADCAST for a socket. |
static final int |
SO_KEEPALIVE |
When the keepalive option is set for a TCP socket and no data has been exchanged across the socket in either direction for 2 hours (NOTE: the actual value is implementation dependent), TCP automatically sends a keepalive probe to the peer. |
static final int |
SO_LINGER |
Specify a linger-on-close timeout. |
static final int |
SO_OOBINLINE |
When the OOBINLINE option is set, any TCP urgent data received on the socket will be received through the socket input stream. |
static final int |
SO_RCVBUF |
Set a hint the size of the underlying buffers used by the platform for incoming network I/O. |
static final int |
SO_REUSEADDR |
Sets SO_REUSEADDR for a socket. |
static final int |
SO_REUSEPORT |
Sets SO_REUSEPORT for a socket. |
static final int |
SO_SNDBUF |
Set a hint the size of the underlying buffers used by the platform for outgoing network I/O. |
static final int |
SO_TIMEOUT |
Set a timeout on blocking Socket operations: |
static final int |
TCP_NODELAY |
Disable Nagle's algorithm for this connection. |
@Native static final int TCP_NODELAY
Valid for TCP only: SocketImpl.
@Native static final int SO_BINDADDR
This option must be specified in the constructor.
Valid for: SocketImpl, DatagramSocketImpl
@Native static final int SO_REUSEADDR
Valid for: DatagramSocketImpl
@Native static final int SO_REUSEPORT
Valid for: SocketImpl, DatagramSocketImpl
@Native static final int SO_BROADCAST
@Native static final int IP_MULTICAST_IF
Valid for Multicast: DatagramSocketImpl
@Native static final int IP_MULTICAST_IF2
@Native static final int IP_MULTICAST_LOOP
@Native static final int IP_TOS
@Native static final int SO_LINGER
Valid only for TCP: SocketImpl
@Native static final int SO_TIMEOUT
ServerSocket.accept(); SocketInputStream.read(); DatagramSocket.receive();
The option must be set prior to entering a blocking operation to take effect. If the timeout expires and the operation would continue to block, java.io.InterruptedIOException is raised. The Socket is not closed in this case.
Valid for all sockets: SocketImpl, DatagramSocketImpl
@Native static final int SO_SNDBUF
@Native static final int SO_RCVBUF
@Native static final int SO_KEEPALIVE
@Native static final int SO_OOBINLINE
void setOption(int optID, Object value) throws SocketException
SocketImpl s; ... s.setOption(SO_LINGER, Integer.valueOf(10)); // OK - set SO_LINGER w/ timeout of 10 sec. s.setOption(SO_LINGER, Double.valueOf(10)); // ERROR - expects java.lang.IntegerIf the requested option is binary, it can be set using this method by a java.lang.Boolean:
s.setOption(TCP_NODELAY, Boolean.TRUE); // OK - enables TCP_NODELAY, a binary option
s.setOption(TCP_NODELAY, Boolean.FALSE); // OK - disables TCP_NODELAY s.setOption(SO_LINGER, Boolean.FALSE); // OK - disables SO_LINGER
optID
- identifies the optionvalue
- the parameter of the socket optionSocketException
- if the option is unrecognized, the socket is closed, or some low-level error occurredObject getOption(int optID) throws SocketException
SocketImpl s; ... Boolean noDelay = (Boolean)(s.getOption(TCP_NODELAY)); if (noDelay.booleanValue()) { // true if TCP_NODELAY is enabled... ... }
For options that take a particular type as a parameter, getOption(int) will return the parameter's value, else it will return java.lang.Boolean.FALSE:
Object o = s.getOption(SO_LINGER); if (o instanceof Integer) { System.out.print("Linger time is " + ((Integer)o).intValue()); } else { // the true type of o is java.lang.Boolean.FALSE; }
optID
- an int
identifying the option to fetchSocketException
- if the socket is closedSocketException
- if optID is unknown along the protocol stack (including the SocketImpl)
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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.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/net/SocketOptions.html