Java Reference
In-Depth Information
Once you have an
InetAddress
instance, you can interrogate it by invoking in-
stancemethodssuchas
byte[] getAddress()
(returntherawIPaddress[innet-
work byte order] of this
InetAddress
object) and
boolean isLoopbackAd-
dress()
(determine whether or not this
InetAddress
instance represents a loop-
back address).
Java 1.4 introduced the abstract
java.net.SocketAddress
class to represent
asocketaddress“withnoprotocolattachment.”Perhapsthisclass'screatoranticipated
that Java would eventually support low-level communication protocols other than the
widely popular Internet Protocol.
SocketAddress
is subclassed by the concrete
java.net.InetSocketAddress
class,whichrepresentsasocketaddressasanIP
addressandaportnumber.Itcanalsorepresentahostnameandaportnumber,andwill
make an attempt to resolve the hostname.
InetSocketAddress
instances are created by invoking constructors such as
InetSocketAddress(InetAddress addr, int port)
. After an instance
hasbeencreated,youcancallmethodssuchas
InetAddress getAddress()
and
int getPort()
to return socket address components.
Socket Options
Aswellassharingtheconceptofsocketaddresses,thevarious
Socket
-suffixedclasses
sharetheconceptofsocketoptions.A
socket option
isaparameterforconfiguringsock-
etbehavior.ThefollowingClanguageconstantsidentifysocketoptionsthatthe
Sock-
et
-suffixed classes support via various methods:
•
TCP_NODELAY
: Disable Nagle's algorithm
option is valid for
Socket
.
•
SO_LINGER
: Specify a linger-on-close timeout. This option is valid for
Socket
.
•
SO_TIMEOUT
:Specifyatimeoutonblockingsocketoperations.(Don'tblock
forever!) This option is valid for
Socket
,
ServerSocket
, and
Data-
gramSocket
.
•
SO_BINDADDR
: Fetch the socket's local address binding. This option is valid
for
Socket
,
ServerSocket
, and
DatagramSocket
.
•
SO_REUSEADDR
: Enable a socket's reuse address. This option is valid for
Socket
,
ServerSocket
, and
DatagramSocket
.
