| java.net.SocketOptions
All known Subclasses: java.net.DatagramSocketImpl, java.net.SocketImpl,
| SocketOptions | | public interface SocketOptions (Code) | | Interface of methods to get/set socket options. This interface is
implemented by: SocketImpl and DatagramSocketImpl.
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
Subclasses of these should override the methods
of this interface in order to support their own options.
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.
NOTE: java.net.SocketImpl, java.net.Socket, java.net.ServerSocket,
java.net.MulticastSocket are found in J2ME CDC profiles such as
J2ME Foundation Profile.
version:
1.32, 10/10/06
author:
David Brown |
| Field Summary | |
| final public static int | IP_MULTICAST_IF
Set which outgoing interface on which to send multicast packets.
Useful on hosts with multiple network interfaces, where applications
want to use other than the system default. | | final public static int | IP_MULTICAST_IF2
Same as above. | | final public static int | IP_MULTICAST_LOOP
This option enables or disables local loopback of multicast datagrams. | | final public static int | IP_TOS
This option sets the type-of-service or traffic class field
in the IP header for a TCP or UDP socket. | | final public static 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). | | final public static int | SO_BROADCAST
Sets SO_BROADCAST for a socket. | | final public static 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. | | final public static int | SO_LINGER
Specify a linger-on-close timeout. | | final public static 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. | | final public static int | SO_RCVBUF
Set a hint the size of the underlying buffers used by the
platform for incoming network I/O. | | final public static int | SO_REUSEADDR
Sets SO_REUSEADDR for a socket. | | final public static int | SO_SNDBUF
Set a hint the size of the underlying buffers used by the
platform for outgoing network I/O. | | final public static int | SO_TIMEOUT
Set a timeout on blocking Socket operations:
ServerSocket.accept();
SocketInputStream.read();
DatagramSocket.receive();
NOTE: java.net.ServerSocket is found in J2ME CDC profiles such as
J2ME Foundation Profile.
The option must be set prior to entering a blocking
operation to take effect. | | final public static int | TCP_NODELAY
Disable Nagle's algorithm for this connection. |
| Method Summary | |
| public Object | getOption(int optID)
Fetch the value of an option. | | public void | setOption(int optID, Object value)
Enable/disable the option specified by optID. |
| IP_MULTICAST_IF | | final public static int IP_MULTICAST_IF(Code) | | Set which outgoing interface on which to send multicast packets.
Useful on hosts with multiple network interfaces, where applications
want to use other than the system default. Takes/returns an InetAddress.
Valid for Multicast: DatagramSocketImpl
See Also: MulticastSocket.setInterface(InetAddress)
See Also: MulitcastSocket.getInterface |
| IP_MULTICAST_LOOP | | final public static int IP_MULTICAST_LOOP(Code) | | This option enables or disables local loopback of multicast datagrams.
This option is enabled by default for Multicast Sockets.
since:
1.4 |
| IP_TOS | | final public static int IP_TOS(Code) | | This option sets the type-of-service or traffic class field
in the IP header for a TCP or UDP socket.
since:
1.4 |
| SO_BINDADDR | | final public static int SO_BINDADDR(Code) | | 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). The default local
address of a socket is INADDR_ANY, meaning any local address on a
multi-homed host. A multi-homed host can use this option to accept
connections to only one of its addresses (in the case of a
ServerSocket or DatagramSocket), or to specify its return address
to the peer (for a Socket or DatagramSocket). The parameter of
this option is an InetAddress.
This option must be specified in the constructor.
Valid for: SocketImpl, DatagramSocketImpl
NOTE: java.net.Socket, java.net.ServerSocket, java.net.SocketImpl
are found in J2ME CDC profiles such as J2ME Foundation Profile.
See Also: Socket.getLocalAddress
See Also: DatagramSocket.getLocalAddress |
| SO_BROADCAST | | final public static int SO_BROADCAST(Code) | | Sets SO_BROADCAST for a socket. This option enables and disables
the ability of the process to send broadcast messages. It is supported
for only datagram sockets and only on networks that support
the concept of a broadcast message (e.g. Ethernet, token ring, etc.),
and it is set by default for DatagramSockets.
since:
1.4 |
| SO_KEEPALIVE | | final public static int SO_KEEPALIVE(Code) | | 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. This probe is a
TCP segment to which the peer must respond.
One of three responses is expected:
1. The peer responds with the expected ACK. The application is not
notified (since everything is OK). TCP will send another probe
following another 2 hours of inactivity.
2. The peer responds with an RST, which tells the local TCP that
the peer host has crashed and rebooted. The socket is closed.
3. There is no response from the peer. The socket is closed.
The purpose of this option is to detect if the peer host crashes.
Valid only for TCP socket: SocketImpl
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setKeepAlive
See Also: Socket.getKeepAlive |
| SO_LINGER | | final public static int SO_LINGER(Code) | | Specify a linger-on-close timeout. This option disables/enables
immediate return from a close() of a TCP Socket. Enabling
this option with a non-zero Integer timeout means that a
close() will block pending the transmission and acknowledgement
of all data written to the peer, at which point the socket is closed
gracefully. Upon reaching the linger timeout, the socket is
closed forcefully, with a TCP RST. Enabling the option with a
timeout of zero does a forceful close immediately. If the specified
timeout value exceeds 65,535 it will be reduced to 65,535.
Valid only for TCP: SocketImpl
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setSoLinger
See Also: Socket.getSoLinger |
| SO_OOBINLINE | | final public static int SO_OOBINLINE(Code) | | When the OOBINLINE option is set, any TCP urgent data received on
the socket will be received through the socket input stream.
When the option is disabled (which is the default) urgent data
is silently discarded.
See Also: Socket.setOOBInline
See Also: Socket.getOOBInline |
| SO_RCVBUF | | final public static int SO_RCVBUF(Code) | | Set a hint the size of the underlying buffers used by the
platform for incoming network I/O. When used in set, this is a
suggestion to the kernel from the application about the size of
buffers to use for the data to be received over the
socket. When used in get, this must return the size of the
buffer actually used by the platform when receiving in data on
this socket.
Valid for all sockets: SocketImpl, DatagramSocketImpl
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setReceiveBufferSize
See Also: Socket.getReceiveBufferSize
See Also: DatagramSocket.setReceiveBufferSize
See Also: DatagramSocket.getReceiveBufferSize |
| SO_REUSEADDR | | final public static int SO_REUSEADDR(Code) | | Sets SO_REUSEADDR for a socket. This is used only for MulticastSockets
in java, and it is set by default for MulticastSockets.
Valid for: DatagramSocketImpl
|
| SO_SNDBUF | | final public static int SO_SNDBUF(Code) | | Set a hint the size of the underlying buffers used by the
platform for outgoing network I/O. When used in set, this is a
suggestion to the kernel from the application about the size of
buffers to use for the data to be sent over the socket. When
used in get, this must return the size of the buffer actually
used by the platform when sending out data on this socket.
Valid for all sockets: SocketImpl, DatagramSocketImpl
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setSendBufferSize
See Also: Socket.getSendBufferSize
See Also: DatagramSocket.setSendBufferSize
See Also: DatagramSocket.getSendBufferSize |
| SO_TIMEOUT | | final public static int SO_TIMEOUT(Code) | | Set a timeout on blocking Socket operations:
ServerSocket.accept();
SocketInputStream.read();
DatagramSocket.receive();
NOTE: java.net.ServerSocket is found in J2ME CDC profiles such as
J2ME Foundation Profile.
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
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setSoTimeout
See Also: ServerSocket.setSoTimeout
See Also: DatagramSocket.setSoTimeout |
| TCP_NODELAY | | final public static int TCP_NODELAY(Code) | | Disable Nagle's algorithm for this connection. Written data
to the network is not buffered pending acknowledgement of
previously written data.
Valid for TCP only: SocketImpl.
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
See Also: Socket.setTcpNoDelay
See Also: Socket.getTcpNoDelay |
| getOption | | public Object getOption(int optID) throws SocketException(Code) | | 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);
}
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
Parameters:
optID - an int identifying the option to fetch the value of the option
throws:
SocketException - if the socket is closed
throws:
SocketException - if optID is unknown along theprotocol stack (including the SocketImpl)
See Also: SocketOptions.setOption(int,java.lang.Object) |
| setOption | | public void setOption(int optID, Object value) throws SocketException(Code) | | 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
NOTE: java.net.SocketImpl is found in J2ME CDC profiles such as
J2ME Foundation Profile.
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
Parameters:
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) |
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