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Class JavaGroups.RemoteMethodCall

java.lang.Object
   |
   +----JavaGroups.MethodCall
           |
           +----JavaGroups.RemoteMethodCall

public class RemoteMethodCall

extends MethodCall

The example code below shows how a client can invoke a remote method call on all members of a group and print the first result returned:

 import java.util.*;
 import JavaGroups.channel.*;
 public class RemoteMethodCallTest {

    public static void main(String args[]) {
        Channel           channel;
        RemoteMethodCall  m;
        Object            ret;
        try {
            channel=new EnsChannel("MethodInvokerTest", null);
            channel.Connect(5000);
            m=new RemoteMethodCall(channel, "Divide", new Integer(3), new Integer(4));
            ret=m.SendGetFirst(5000);  // wait for maximum 5 seconds
            System.out.println( ret != null ? ret : "Response is null");
        }
        catch(Exception e) {
            System.err.println(e);
        }
        finally {
            channel.Disconnect();
            channel.Destroy();
        }
    }

 }
 

The code first creates a channel and connects to it. Then (in bold letters) a RemoteMethodCall object is created which uses the channel to send messages and receive responses. (Actually, a SyncCall object is used to send a message synchronously and wait for the first (or the first N) responses). Method SendGetFirst sends the method call (as a Message) to all members of the group, converts the first reponse message to an object and returns it to the caller. Method SendGetN does essentially the same, but returns N results (e.g. waits for all groups members to respond). Note that N=0 does not wait for a response.

In the example a method called "Divide" will be called with two arguments.

The corresponding code for the server side (dispatching of message to method and returning of result(s) can written using an instance of MethodInvoker.

If an asynchronous (oneway) remote method call is wanted, method SendGetN can be used by setting expected_responses to 0. In this case, no responses will be returned (even if the method itself does return a result).

See Also:

MethodInvoker, Dispatcher

RemoteMethodCall(Transport)

RemoteMethodCall(Transport, String)

RemoteMethodCall(Transport, String, Object)

RemoteMethodCall(Transport, String, Object, Object)

RemoteMethodCall(Transport, String, Object, Object, Object)

RemoteMethodCall(Transport, String, String)

RemoteMethodCall(Transport, String, String, Object)

RemoteMethodCall(Transport, String, String, Object, Object)

RemoteMethodCall(Transport, String, String, Object, Object, Object)

main(String[])

Send(Object, boolean, long)

SendGetFirst(long)

SendGetN(int, long)

Invokes a method on all members of the group and returns more than one response.

 public RemoteMethodCall(Transport t)

 public RemoteMethodCall(Transport t,
                         String name)

 public RemoteMethodCall(Transport t,
                         String name,
                         String funclet_name)

 public RemoteMethodCall(Transport t,
                         String name,
                         Object arg1)

 public RemoteMethodCall(Transport t,
                         String name,
                         String funclet_name,
                         Object arg1)

 public RemoteMethodCall(Transport t,
                         String name,
                         Object arg1,
                         Object arg2)

 public RemoteMethodCall(Transport t,
                         String name,
                         String funclet_name,
                         Object arg1,
                         Object arg2)

 public RemoteMethodCall(Transport t,
                         String name,
                         Object arg1,
                         Object arg2,
                         Object arg3)

 public RemoteMethodCall(Transport t,
                         String name,
                         String funclet_name,
                         Object arg1,
                         Object arg2,
                         Object arg3)

 public Object Send(Object dest,
                    boolean oneway,
                    long timeout) throws Exception

 public Object SendGetFirst(long timeout) throws Exception

 public Vector SendGetN(int expected_responses,
                        long timeout) throws Exception

Invokes a method on all members of the group and returns more than one response. (Note that N should not be greater than the size of the group, or at least the timeout should be sety to greater than 0, otherwise the call waits forever). All responses are converted to objects and returned in a vector. If any method call threw an exception, the vector will contain it instead of a normal object. It is the caller's duty to check whether there are any exceptions present in the vector.

SendGetN(0, 0) can be used to send a method call to all members without expecting any responses

 public static void main(String args[])

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