Class OncRpcPortmapClient
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 invalid input: '<' 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
.
- Version:
- $Revision: 1.1.1.1 $ $Date: 2003/08/13 12:03:41 $ $State: Exp $ $Locker: $
- Author:
- Harald Albrecht
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
Well-known port where the portmap process can be found on Internet hosts.static final int
Program number of the portmapper as defined in RFC 1832.static final int
Program version number of the portmapper as defined in RFC 1832.protected OncRpcClient
The particular transport-specific ONC/RPC client object used for talking to the portmapper. -
Constructor Summary
ConstructorsConstructorDescriptionConstructs 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
(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
(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
Modifier and TypeMethodDescriptionvoid
close()
Closes the connection to the portmapper.Returns the client proxy object used for communicating with the portmapper.int
getPort
(int program, int version, int protocol) Asks the portmapper thisOncRpcPortmapClient
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}.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.
-
Field Details
-
PMAP_PORT
public static final int PMAP_PORTWell-known port where the portmap process can be found on Internet hosts.- See Also:
-
PMAP_PROGRAM
public static final int PMAP_PROGRAMProgram number of the portmapper as defined in RFC 1832.- See Also:
-
PMAP_VERSION
public static final int PMAP_VERSIONProgram version number of the portmapper as defined in RFC 1832.- See Also:
-
portmapClient
The particular transport-specific ONC/RPC client object used for talking to the portmapper.
-
-
Constructor Details
-
OncRpcPortmapClient
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.- Parameters:
host
- Host where to contact the portmapper.- Throws:
OncRpcException
- if an ONC/RPC error occurs.IOException
- if an I/O error occurs.
-
OncRpcPortmapClient
Constructs and initializes an ONC/RPC client object, which can communicate with the portmapper at the given host using the speicified protocol.- Parameters:
host
- Host where to contact the portmapper.protocol
- Protocol to use for contacting the portmapper. This can be eitherOncRpcProtocols.ONCRPC_UDP
orOncRpcProtocols.ONCRPC_TCP
(HTTP is currently not supported).- Throws:
OncRpcException
- if an ONC/RPC error occurs.IOException
- if an I/O error occurs.
-
OncRpcPortmapClient
public OncRpcPortmapClient(InetAddress host, int protocol, int timeout) throws OncRpcException, IOException Constructs and initializes an ONC/RPC client object, which can communicate with the portmapper at the given host using the speicified protocol.- Parameters:
host
- Host where to contact the portmapper.protocol
- Protocol to use for contacting the portmapper. This can be eitherOncRpcProtocols.ONCRPC_UDP
orOncRpcProtocols.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.- Throws:
OncRpcException
- if an ONC/RPC error occurs.IOException
- if an I/O error occurs.
-
-
Method Details
-
close
Closes the connection to the portmapper.- Throws:
OncRpcException
-
getOncRpcClient
Returns the client proxy object used for communicating with the portmapper.- Returns:
- portmap client proxy object (subclass of
OncRpcClient
).
-
getPort
Asks the portmapper thisOncRpcPortmapClient
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}.- Parameters:
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 theOncRpcProtocols
interface.- Returns:
- port number of ONC/RPC server in question.
- Throws:
OncRpcException
- if the portmapper is not available (detail isOncRpcException.RPC_PMAPFAILURE
).OncRpcProgramNotRegisteredException
- if the requested program is not available.
-
setPort
Register an ONC/RPC with the given program number, version and protocol at the given port with the portmapper.- Parameters:
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 theOncRpcProtocols
constants.port
- The port number where the ONC/RPC server can be reached.- Returns:
- Indicates whether registration succeeded (
true
) or was denied by the portmapper (false
). - Throws:
OncRpcException
- if the portmapper is not available (detail isOncRpcException.RPC_PMAPFAILURE
).
-
unsetPort
Unregister an ONC/RPC with the given program number and version. The portmapper will remove all entries with the same program number and version, regardless of the protocol and port number.- Parameters:
program
- The number of the program to be unregistered.version
- The version number of the program.- Returns:
- Indicates whether deregistration succeeded (
true
) or was denied by the portmapper (false
). - Throws:
OncRpcException
- if the portmapper is not available (detail isOncRpcException.RPC_PMAPFAILURE
).
-
listServers
Retrieves a list of all registered ONC/RPC servers at the same host as the contacted portmapper.- Returns:
- vector of server descriptions (see
class
OncRpcServerIdent
). - Throws:
OncRpcException
- if the portmapper is not available (detail isOncRpcException.RPC_PMAPFAILURE
).
-
ping
Ping the portmapper (try to call procedure 0).- Throws:
OncRpcException
- if the portmapper is not available (detail isOncRpcException.RPC_PMAPFAILURE
).
-