SocketOptions JDK 1.6)

Methods

public Object getOption (int optID) throws SocketException

Fetch the value of an option.

Fetch the value of an option. Binary options will return java.lang.Boolean(true) if enabled, java.lang.Boolean(false) if disabled, e.g.:

 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 paramter'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);
 }

Returns: the value of the option
Parameters:
- optID - an int identifying the option to fetch
Throws:
- SocketException - if the socket is closed
- SocketException - if optID is unknown along the protocol stack (including the SocketImpl)
See Also: SocketOptions.setOption(int, java.lang.Object),

public void setOption (int optID, Object value) throws SocketException

Enable/disable the option specified by optID.

Enable/disable the option specified by optID. If the option
is to be enabled, and it takes an option-specific "value", this is
passed in value. The actual type of value is option-specific,
and it is an error to pass something that isn't of the expected type:


 SocketImpl s;
 ...
 s.setOption(SO_LINGER, new Integer(10));
    // OK - set SO_LINGER w/ timeout of 10 sec.
 s.setOption(SO_LINGER, new Double(10));
    // ERROR - expects java.lang.Integer

If the requested option is binary, it can be set using this method by
a java.lang.Boolean:


 s.setOption(TCP_NODELAY, new Boolean(true));
    // OK - enables TCP_NODELAY, a binary option

Any option can be disabled using this method with a Boolean(false):


 s.setOption(TCP_NODELAY, new Boolean(false));
    // OK - disables TCP_NODELAY
 s.setOption(SO_LINGER, new Boolean(false));
    // OK - disables SO_LINGER

For an option that has a notion of on and off, and requires
a non-boolean parameter, setting its value to anything other than
Boolean(false) implicitly enables it.

Throws SocketException if the option is unrecognized,
the socket is closed, or some low-level error occurred

Parameters:
- optID - identifies the option
- value - the parameter of the socket option
Throws:
- SocketException - if the option is unrecognized, the socket is closed, or some low-level error occurred
See Also: SocketOptions.getOption(int),

Fields

Hide/Show inherited fields

publicfinalstatic int IP_MULTICAST_IF = "16"

Set which outgoing interface on which to send multicast packets.

publicfinalstatic int IP_MULTICAST_IF2 = "31"

Same as above.

publicfinalstatic int IP_MULTICAST_LOOP = "18"

This option enables or disables local loopback of multicast datagrams.

publicfinalstatic int IP_TOS = "3"

This option sets the type-of-service or traffic class field in the IP header for a TCP or UDP socket.

publicfinalstatic int SO_BINDADDR = "15"

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).

publicfinalstatic int SO_BROADCAST = "32"

Sets SO_BROADCAST for a socket.

publicfinalstatic int SO_KEEPALIVE = "8"

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.

publicfinalstatic int SO_LINGER = "128"

Specify a linger-on-close timeout.

publicfinalstatic int SO_OOBINLINE = "4099"

When the OOBINLINE option is set, any TCP urgent data received on the socket will be received through the socket input stream.

publicfinalstatic int SO_RCVBUF = "4098"

Set a hint the size of the underlying buffers used by the platform for incoming network I/O.

publicfinalstatic int SO_REUSEADDR = "4"

Sets SO_REUSEADDR for a socket.

publicfinalstatic int SO_SNDBUF = "4097"

Set a hint the size of the underlying buffers used by the platform for outgoing network I/O.

publicfinalstatic int SO_TIMEOUT = "4102"

Set a timeout on blocking Socket operations:

 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
See Also: Socket.setSoTimeout(int), ServerSocket.setSoTimeout(int), DatagramSocket.setSoTimeout(int),

publicfinalstatic int TCP_NODELAY = "1"

Disable Nagle's algorithm for this connection.