Class OncRpcPortmapClient


  • public class OncRpcPortmapClient
    extends java.lang.Object
    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.

    Version:
    $Revision: 1.1.1.1 $ $Date: 2003/08/13 12:03:41 $ $State: Exp $ $Locker: $
    Author:
    Harald Albrecht
    See Also:
    OncRpcClient
    • Field Summary

      Fields 
      Modifier and Type Field Description
      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

      Constructors 
      Constructor Description
      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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      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

      • PMAP_PORT

        public static final int PMAP_PORT
        Well-known port where the portmap process can be found on Internet hosts.
        See Also:
        Constant Field Values
      • PMAP_PROGRAM

        public static final int PMAP_PROGRAM
        Program number of the portmapper as defined in RFC 1832.
        See Also:
        Constant Field Values
      • PMAP_VERSION

        public static final int PMAP_VERSION
        Program version number of the portmapper as defined in RFC 1832.
        See Also:
        Constant Field Values
      • portmapClient

        protected OncRpcClient portmapClient
        The particular transport-specific ONC/RPC client object used for talking to the portmapper.
    • Constructor Detail

      • OncRpcPortmapClient

        public OncRpcPortmapClient​(java.net.InetAddress host)
                            throws OncRpcException,
                                   java.io.IOException
        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.
        java.io.IOException - if an I/O error occurs.
      • OncRpcPortmapClient

        public OncRpcPortmapClient​(java.net.InetAddress host,
                                   int protocol)
                            throws OncRpcException,
                                   java.io.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 either OncRpcProtocols.ONCRPC_UDP or OncRpcProtocols.ONCRPC_TCP (HTTP is currently not supported).
        Throws:
        OncRpcException - if an ONC/RPC error occurs.
        java.io.IOException - if an I/O error occurs.
      • OncRpcPortmapClient

        public OncRpcPortmapClient​(java.net.InetAddress host,
                                   int protocol,
                                   int timeout)
                            throws OncRpcException,
                                   java.io.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 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.
        Throws:
        OncRpcException - if an ONC/RPC error occurs.
        java.io.IOException - if an I/O error occurs.
    • Method Detail

      • getOncRpcClient

        public OncRpcClient getOncRpcClient()
        Returns the client proxy object used for communicating with the portmapper.
        Returns:
        portmap client proxy object (subclass of OncRpcClient).
      • getPort

        public int getPort​(int program,
                           int version,
                           int protocol)
                    throws OncRpcException
        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}.
        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 the OncRpcProtocols interface.
        Returns:
        port number of ONC/RPC server in question.
        Throws:
        OncRpcException - if the portmapper is not available (detail is OncRpcException.RPC_PMAPFAILURE).
        OncRpcProgramNotRegisteredException - if the requested program is not available.
      • setPort

        public boolean setPort​(int program,
                               int version,
                               int protocol,
                               int port)
                        throws OncRpcException
        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 the OncRpcProtocols 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 is OncRpcException.RPC_PMAPFAILURE).
      • unsetPort

        public boolean unsetPort​(int program,
                                 int version)
                          throws OncRpcException
        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 is OncRpcException.RPC_PMAPFAILURE).