Java Reference
In-Depth Information
ing to set an option the channel doesn't support throws an
UnsupportedOperationEx
ception
.
Example 11-7
is a simple program to list all supported socket options for the different
types of network channels.
Example 11-7. Listing supported options
import
java.io.*
;
import
java.net.*
;
import
java.nio.channels.*
;
public
class
OptionSupport
{
public
static
void
main
(
String
[]
args
)
throws
IOException
{
printOptions
(
SocketChannel
.
open
());
printOptions
(
ServerSocketChannel
.
open
());
printOptions
(
AsynchronousSocketChannel
.
open
());
printOptions
(
AsynchronousServerSocketChannel
.
open
());
printOptions
(
DatagramChannel
.
open
());
}
private
static
void
printOptions
(
NetworkChannel
channel
)
throws
IOException
{
System
.
out
.
println
(
channel
.
getClass
().
getSimpleName
()
+
" supports:"
);
for
(
SocketOption
<?>
option
:
channel
.
supportedOptions
())
{
System
.
out
.
println
(
option
.
name
()
+
": "
+
channel
.
getOption
(
option
));
}
System
.
out
.
println
();
channel
.
close
();
}
}
Here's the output showing which options are supported by which types of channels, and
what the default values are:
SocketChannelImpl supports:
SO_OOBINLINE: false
SO_REUSEADDR: false
SO_LINGER: -1
SO_KEEPALIVE: false
IP_TOS: 0
SO_SNDBUF: 131072
SO_RCVBUF: 131072
TCP_NODELAY: false
ServerSocketChannelImpl supports:
SO_REUSEADDR: true
SO_RCVBUF: 131072
UnixAsynchronousSocketChannelImpl supports:
SO_KEEPALIVE: false
