org.acplt.oncrpc.OncRpcPortmapClient
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java.lang.Object
public class OncRpcPortmapClient
The class OncRpcPortmapClient is a specialized ONC/RPC client,
which can talk to the portmapper on a given host using the famous
UDP/IP datagram-oriented internet protocol. In addition, it is also possible
to contact portmappers using TCP/IP. For this, the constructor of the
OncRpcPortmapClient class also accepts a protocol parameter
(OncRpcPortmapClient(InetAddress, int)).
Technically spoken, instances of OncRpcPortmapClient are proxy objects.
OncRpcPortmapClient objects currently speak protocol version
2. The newer transport-independent protocol versions 3 and 4 are
not supported as the transport-independent ONC/RPC implementation is not
that widely in use due to the brain-damaged design of XTI. If you should
ever have programmed using XTI (transport independent interface) then you'll
know what I mean and probably agree with me. Otherwise, in case you find XTI
the best thing since the Win32 API, please implement the rpcbind protocol
versions 3 and 4 and give it to the community -- thank you.
Here are some simple examples of how to use the portmapper proxy object. We first start with one of the most interesting operations, which can be performed on portmappers, querying the port of a local or remote ONC/RPC server.
To query the port number of an ONC/RPC server, we need to contact the
portmapper at the host machine where the server is running. The following
code snippet just contacts the local portmapper. try blocks
are ommited for brevity -- but remember that you almost allways need to catch
OncRpcException as well as IOException.
OncRpcPortmapClient portmap =
new OncRpcPortmapClient(InetAddress.getByName("localhost"));
With the portmapper proxy object in our hands we can now ask for the port
number of a particular ONC/RPC server. In this (ficious) example we ask for
the ONC/RPC program (server) number 0x49678 (by coincidence this
happens to be the program number of the ACPLT/KS
protocol). To ask for the port number of a given program number, use the
getPort(...) method.
int port;
try {
port = portmap.getPort(0x49678, 1, OncRpcProtocols.ONCRPC_UDP);
} catch ( OncRpcProgramNotRegisteredException e ) {
System.out.println("ONC/RPC program server not found");
System.exit(0);
} catch ( OncRpcException e ) {
System.out.println("Could not contact portmapper:");
e.printStackTrace(System.out);
System.exit(0);
}
System.out.println("Program available at port " + port);
In the call to getPort(...), the
first parameter specifies the ONC/RPC program number, the secondm parameter
specifies the program's version number, and the third parameter specifies
the IP protocol to use when issueing ONC/RPC calls. Currently, only
OncRpcProtocols.ONCRPC_UDP and OncRpcProtocols.ONCRPC_TCP are
supported. But who needs other protocols anyway?!
In case getPort(...) succeeds, it
returns the number of the port where the appropriate ONC/RPC server waits
for incoming ONC/RPC calls. If the ONC/RPC program is not registered with
the particular ONC/RPC portmapper, an OncRpcProgramNotRegisteredException
is thrown (which is a subclass of OncRpcException with a detail
reason of OncRpcException.RPC_PROGNOTREGISTERED.
A second typical example of how to use the portmapper is retrieving a
list of the currently registered servers. We use the
listServers() method for this purpose in the
following example, and print the list we got.
OncRpcServerIdent [] list = null;
try {
list = portmap.listServers();
} catch ( OncRpcException e ) {
e.printStackTrace(System.out);
System.exit(20);
}
for ( int i = 0; i < list.length; ++i ) {
System.out.println(list[i].program + " " + list[i].version + " "
+ list[i].protocol + " " + list[i].port);
}
When you do not need the client proxy object any longer, you should
return the resources it occupies to the system. Use the close()
method for this.
portmap.close(); portmap = null; // Hint to the garbage (wo)man
For another code example, please consult
src/tests/org/acplt/oncrpc/PortmapGetPortTest.java.
OncRpcClient| Field Summary | |
|---|---|
static int |
PMAP_PORT
Well-known port where the portmap process can be found on Internet hosts. |
static int |
PMAP_PROGRAM
Program number of the portmapper as defined in RFC 1832. |
static int |
PMAP_VERSION
Program version number of the portmapper as defined in RFC 1832. |
protected OncRpcClient |
portmapClient
The particular transport-specific ONC/RPC client object used for talking to the portmapper. |
| Constructor Summary | |
|---|---|
OncRpcPortmapClient(java.net.InetAddress host)
Constructs and initializes an ONC/RPC client object, which can communicate with the portmapper at the specified host using the UDP/IP datagram-oriented internet protocol. |
|
OncRpcPortmapClient(java.net.InetAddress host,
int protocol)
Constructs and initializes an ONC/RPC client object, which can communicate with the portmapper at the given host using the speicified protocol. |
|
OncRpcPortmapClient(java.net.InetAddress host,
int protocol,
int timeout)
Constructs and initializes an ONC/RPC client object, which can communicate with the portmapper at the given host using the speicified protocol. |
|
| Method Summary | |
|---|---|
void |
close()
Closes the connection to the portmapper. |
OncRpcClient |
getOncRpcClient()
Returns the client proxy object used for communicating with the portmapper. |
int |
getPort(int program,
int version,
int protocol)
Asks the portmapper this OncRpcPortmapClient object is
a proxy for, for the port number of a particular ONC/RPC server
identified by the information tuple {program number, program version,
protocol}. |
OncRpcServerIdent[] |
listServers()
Retrieves a list of all registered ONC/RPC servers at the same host as the contacted portmapper. |
void |
ping()
Ping the portmapper (try to call procedure 0). |
boolean |
setPort(int program,
int version,
int protocol,
int port)
Register an ONC/RPC with the given program number, version and protocol at the given port with the portmapper. |
boolean |
unsetPort(int program,
int version)
Unregister an ONC/RPC with the given program number and version. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static final int PMAP_PORT
public static final int PMAP_PROGRAM
public static final int PMAP_VERSION
protected OncRpcClient portmapClient
| Constructor Detail |
|---|
public OncRpcPortmapClient(java.net.InetAddress host)
throws OncRpcException,
java.io.IOException
host - Host where to contact the portmapper.
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.public OncRpcPortmapClient(java.net.InetAddress host,
int protocol)
throws OncRpcException,
java.io.IOException
host - Host where to contact the portmapper.protocol - Protocol to use for contacting the portmapper. This
can be either OncRpcProtocols.ONCRPC_UDP or
OncRpcProtocols.ONCRPC_TCP (HTTP is currently
not supported).
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.public OncRpcPortmapClient(java.net.InetAddress host,
int protocol,
int timeout)
throws OncRpcException,
java.io.IOException
host - Host where to contact the portmapper.protocol - Protocol to use for contacting the portmapper. This
can be either OncRpcProtocols.ONCRPC_UDP or
OncRpcProtocols.ONCRPC_TCP (HTTP is currently
not supported).timeout - Timeout in milliseconds for connection operation. This
parameter applies only when using TCP/IP for talking to the
portmapper. A negative timeout indicates that the
implementation-specific timeout setting of the JVM and java.net
implementation should be used instead.
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.| Method Detail |
|---|
public void close()
throws OncRpcException
OncRpcExceptionpublic OncRpcClient getOncRpcClient()
OncRpcClient).public int getPort(int program,
int version,
int protocol)
throws OncRpcException
OncRpcPortmapClient object is
a proxy for, for the port number of a particular ONC/RPC server
identified by the information tuple {program number, program version,
protocol}.
program - Program number of the remote procedure call in question.version - Program version number.protocol - Protocol lateron used for communication with the
ONC/RPC server in question. This can be one of the protocols constants
defined in the OncRpcProtocols interface.
OncRpcException - if the portmapper is not available (detail is
OncRpcException.RPC_PMAPFAILURE).
OncRpcProgramNotRegisteredException - if the requested program
is not available.public boolean setPort(int program,
int version,
int protocol,
int port)
throws OncRpcException
program - The number of the program to be registered.version - The version number of the program.protocol - The protocol spoken by the ONC/RPC server. Can be one
of the OncRpcProtocols constants.port - The port number where the ONC/RPC server can be reached.
true) or
was denied by the portmapper (false).
OncRpcException - if the portmapper is not available (detail is
OncRpcException.RPC_PMAPFAILURE).public boolean unsetPort(int program,
int version)
throws OncRpcException
program - The number of the program to be unregistered.version - The version number of the program.
true)
or was denied by the portmapper (false).
OncRpcException - if the portmapper is not available (detail is
OncRpcException.RPC_PMAPFAILURE).public OncRpcServerIdent[] listServers()
throws OncRpcException
OncRpcServerIdent).
OncRpcException - if the portmapper is not available (detail is
OncRpcException.RPC_PMAPFAILURE).public void ping()
throws OncRpcException
OncRpcException - if the portmapper is not available (detail is
OncRpcException.RPC_PMAPFAILURE).
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