org.acplt.oncrpc
Class OncRpcUdpClient

java.lang.Object
  |
  +--org.acplt.oncrpc.OncRpcClient
        |
        +--org.acplt.oncrpc.OncRpcUdpClient
Direct Known Subclasses:
OncRpcPortmapClient

public class OncRpcUdpClient
extends OncRpcClient

ONC/RPC client which communicates with ONC/RPC servers over the network using the datagram-oriented protocol UDP/IP.


Field Summary
protected  XdrUdpDecodingStream receivingXdr
          XDR decoding stream used when receiving replies via UDP/IP from an ONC/RPC server.
protected  int retransmissionMode
          Retransmission mode used when resending ONC/RPC calls.
protected  int retransmissionTimeout
          Retransmission timeout used for resending ONC/RPC calls when an ONC/RPC server does not answer fast enough.
protected  XdrUdpEncodingStream sendingXdr
          XDR encoding stream used for sending requests via UDP/IP to an ONC/RPC server.
private  java.net.DatagramSocket socket
          UDP socket used for datagram-based communication with an ONC/RPC server.
private  OncRpcUdpSocketHelper socketHelper
          Socket helper object supplying missing methods for JDK 1.1 backwards compatibility.
 
Fields inherited from class org.acplt.oncrpc.OncRpcClient
auth, host, port, program, timeout, version, xid
 
Constructor Summary
OncRpcUdpClient(java.net.InetAddress host, int program, int version, int port)
          Constructs a new OncRpcUdpClient object, which connects to the ONC/RPC server at host for calling remote procedures of the given { program, version }.
OncRpcUdpClient(java.net.InetAddress host, int program, int version, int port, int bufferSize)
          Constructs a new OncRpcUdpClient object, which connects to the ONC/RPC server at host for calling remote procedures of the given { program, version }.
 
Method Summary
 void broadcastCall(int procedureNumber, XdrAble params, XdrAble result, OncRpcBroadcastListener listener)
          Broadcast a remote procedure call to several ONC/RPC servers.
 void call(int procedureNumber, XdrAble params, XdrAble result)
          Calls a remote procedure on an ONC/RPC server.
 void close()
          Close the connection to an ONC/RPC server and free all network-related resources.
 int getRetransmissionMode()
          Retrieve the current retransmission mode set for retransmission of lost ONC/RPC calls.
 int getRetransmissionTimeout()
          Retrieve the current retransmission timeout set for remote procedure calls.
 void setRetransmissionMode(int mode)
          Set the retransmission mode for lost remote procedure calls.
 void setRetransmissionTimeout(int milliseconds)
          Set the retransmission timout for remote procedure calls to wait for an answer from the ONC/RPC server before resending the call.
 
Methods inherited from class org.acplt.oncrpc.OncRpcClient
getAuth, getTimeout, newOncRpcClient, newOncRpcClient, nextXid, setAuth, setTimeout
 
Methods inherited from class java.lang.Object
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait
 

Field Detail

socket

private java.net.DatagramSocket socket
UDP socket used for datagram-based communication with an ONC/RPC server.

socketHelper

private OncRpcUdpSocketHelper socketHelper
Socket helper object supplying missing methods for JDK 1.1 backwards compatibility. So much for compile once, does not run everywhere.

sendingXdr

protected XdrUdpEncodingStream sendingXdr
XDR encoding stream used for sending requests via UDP/IP to an ONC/RPC server.

receivingXdr

protected XdrUdpDecodingStream receivingXdr
XDR decoding stream used when receiving replies via UDP/IP from an ONC/RPC server.

retransmissionTimeout

protected int retransmissionTimeout
Retransmission timeout used for resending ONC/RPC calls when an ONC/RPC server does not answer fast enough. The default retransmission timeout is identical to the overall timeout for ONC/RPC calls (thus UDP/IP-based clients will not retransmit lost calls).
See Also:
retransmissionMode, OncRpcClient.setTimeout(int)

retransmissionMode

protected int retransmissionMode
Retransmission mode used when resending ONC/RPC calls. Default mode is fixed timeout mode.
See Also:
OncRpcUdpRetransmissionMode
Constructor Detail

OncRpcUdpClient

public OncRpcUdpClient(java.net.InetAddress host,
                       int program,
                       int version,
                       int port)
                throws OncRpcException,
                       java.io.IOException
Constructs a new OncRpcUdpClient object, which connects to the ONC/RPC server at host for calling remote procedures of the given { program, version }.

Note that the construction of an OncRpcUdpProtocolClient object will result in communication with the portmap process at host if port is 0.

Parameters:
host - The host where the ONC/RPC server resides.
program - Program number of the ONC/RPC server to call.
version - Program version number.
port - The port number where the ONC/RPC server can be contacted. If 0, then the OncRpcUdpClient object will ask the portmapper at host for the port number.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.

OncRpcUdpClient

public OncRpcUdpClient(java.net.InetAddress host,
                       int program,
                       int version,
                       int port,
                       int bufferSize)
                throws OncRpcException,
                       java.io.IOException
Constructs a new OncRpcUdpClient object, which connects to the ONC/RPC server at host for calling remote procedures of the given { program, version }.

Note that the construction of an OncRpcUdpProtocolClient object will result in communication with the portmap process at host if port is 0.

Parameters:
host - The host where the ONC/RPC server resides.
program - Program number of the ONC/RPC server to call.
version - Program version number.
port - The port number where the ONC/RPC server can be contacted. If 0, then the OncRpcUdpClient object will ask the portmapper at host for the port number.
bufferSize - The buffer size used for sending and receiving UDP datagrams.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Method Detail

close

public void close()
           throws OncRpcException
Close the connection to an ONC/RPC server and free all network-related resources. Well -- at least hope, that the Java VM will sometimes free some resources. Sigh.
Throws:
OncRpcException - if an ONC/RPC error occurs.
Overrides:
close in class OncRpcClient

call

public void call(int procedureNumber,
                 XdrAble params,
                 XdrAble result)
          throws OncRpcException
Calls a remote procedure on an ONC/RPC server.

The OncRpcUdpClient uses a similar timeout scheme as the genuine Sun C implementation of ONC/RPC: it starts with a timeout of one second when waiting for a reply. If no reply is received within this time frame, the client doubles the timeout, sends a new request and then waits again for a reply. In every case the client will wait no longer than the total timeout set through the OncRpcClient.setTimeout(int) method.

Parameters:
procedureNumber - Procedure number of the procedure to call.
parameters - The parameters of the procedure to call, contained in an object which implements the XdrAble interface.
result - The object receiving the result of the procedure call.
Throws:
OncRpcException - if an ONC/RPC error occurs.
Overrides:
call in class OncRpcClient

broadcastCall

public void broadcastCall(int procedureNumber,
                          XdrAble params,
                          XdrAble result,
                          OncRpcBroadcastListener listener)
                   throws OncRpcException
Broadcast a remote procedure call to several ONC/RPC servers. For this you'll need to specify either a multicast address or the subnet's broadcast address when creating a OncRpcUdpClient. For every reply received, an event containing the reply is sent to the OncRpcBroadcastListener listener, which is the last parameter to the this method.

In contrast to the method, broadcastCall will only send the ONC/RPC call once. It will then wait for answers until the timeout as set by {@link #setTimeout(int) expires without resending the reply.

Note that you might experience unwanted results when using authentication types other than OncRpcClientAuthNone, causing messed up authentication protocol handling objects. This depends on the type of authentication used. For AUTH_UNIX nothing bad happens as long as none of the servers replies with a shorthand verifier. If it does, then this shorthand will be used on all subsequent ONC/RPC calls, something you probably do not want at all.

Parameters:
procedureNumber - Procedure number of the procedure to call.
parameters - The parameters of the procedure to call, contained in an object which implements the XdrAble interface.
result - The object receiving the result of the procedure call. Note that this object is reused to deserialize all incomming replies one after another.
listener - Listener which will get an OncRpcBroadcastEvent for every reply received.
Throws:
OncRpcException - if an ONC/RPC error occurs.

setRetransmissionMode

public void setRetransmissionMode(int mode)
Set the retransmission mode for lost remote procedure calls. The default retransmission mode is OncRpcUdpRetransmissionMode.FIXED.
Parameters:
mode - Retransmission mode (either fixed or exponential).

getRetransmissionMode

public int getRetransmissionMode()
Retrieve the current retransmission mode set for retransmission of lost ONC/RPC calls.
Returns:
Current retransmission mode.

setRetransmissionTimeout

public void setRetransmissionTimeout(int milliseconds)
Set the retransmission timout for remote procedure calls to wait for an answer from the ONC/RPC server before resending the call. The default retransmission timeout is the 30 seconds. The retransmission timeout must be > 0. To disable retransmission of lost calls, set the retransmission timeout to be the same value as the timeout.
Parameters:
milliseconds - Timeout in milliseconds. A timeout of zero indicates batched calls.

getRetransmissionTimeout

public int getRetransmissionTimeout()
Retrieve the current retransmission timeout set for remote procedure calls.
Returns:
Current retransmission timeout.