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Class JavaGroups.MethodInvoker

java.lang.Object
   |
   +----JavaGroups.MethodInvoker

public class MethodInvoker

extends Object

implements MessageListener

import java.util.*;
import JavaGroups.channel.*;

public class MethodInvokerTest {
    private Channel channel;
    private MethodInvoker inv;

    public void Start() throws Exception {
        channel=new EnsChannel("MethodInvokerTest", null);
        channel.Connect(1000);
        inv=new MethodInvoker(channel, this);
    }

    public Date GetCurrentDate() {return new Date();}

    public float Divide(Integer x, Integer y) {
        return (float)x.intValue()/y.intValue();
    }

    public void ThrowMe() throws Exception {
        System.out.println("ThrowMe(): throwing exception");
        throw new Exception("hello, this is a dummy exception from ThrowMe");
    }

    public long GetCurrentTimeMillis() {return System.currentTimeMillis();}

    public static void main(String args[]) {
        MethodInvokerTest t=new MethodInvokerTest();
        try {
	    t.Start();
        }
        catch(Exception e) {
            System.err.println(e);
        }
    }

}
 

The code first creates a channel object and connects to it. This allows clients which connect to a channel with the same name to multicast method calls to all channels with the same name. Then a MethodInvoker object is created. The first argument is a transport used to receive messages and send responses. The second is the object on which the method calls will be invoked.

Methods to be invoked by MethodInvoker have to have Objects because primitive parameters (e.g. 'int') are currently not supported as Class objects for primitive types cannot be serialized. As consequence, methods to be invoked remotely (via MethodInvoker) have to have Objects as parameters, rather than primitive types. Return values, however, can be primitive types.

Note that a server role can at any time assume a client role by creating and sending remote method calls.

See Also:

RemoteMethodCall, Dispatcher

MethodInvoker(Transport, boolean)

Creates a new MethodInvoker and (optionally) a PullPushAdapter and directs messages received by the PullPushAdapter to the MethodInvoker.

MethodInvoker(Transport, Object, boolean)

Creates a new MethodInvoker and (optionally) a PullPushAdapter and directs messages received by the PullPushAdapter to the MethodInvoker.

AddFunclet(Object, String, Object)

A funclet handles requests on behalf of the target object.

AddTargetObject(Object)

GetState()

HoldRequests()

Every request received after this call will be stored in a queue instead of being invoked on the target object(s).

main(String[])

Receive(Message)

ReleaseRequests()

Removes all requests from the queue, invokes them on the target object(s) and resets the queueing flag.

RemoveAllTargetObjects()

RemoveTargetObject(Object)

SetMethodLookup(MethodLookup)

Allows to set a method resolution method which will be executed by the underlying MethodCall object to resolve the method.

SetState(Serializable)

 public MethodInvoker(Transport t,
                      boolean create_pull_push_adapter)

Creates a new MethodInvoker and (optionally) a PullPushAdapter and directs messages received by the PullPushAdapter to the MethodInvoker.

Parameters:

t - Transport over which to send responses

create_pull_push_adapter - If true, a new instance of PullPushAdapter is created and messages received by it redirected to the MethodInvoker. Setting this parameter to false allows to create one's own PullPushAdapter (to invoke Receive).

 public MethodInvoker(Transport t,
                      Object target,
                      boolean create_pull_push_adapter)

Creates a new MethodInvoker and (optionally) a PullPushAdapter and directs messages received by the PullPushAdapter to the MethodInvoker.

Parameters:

t - Transport over which to send responses

target - Adds the object to the MethodInvoker's target set. Any time a message is received, it will be dispatched (in the form of a method invocation) to all objects in the target set.

create_pull_push_adapter - If true, a new instance of PullPushAdapter is created and messages received by it redirected to the MethodInvoker. Setting this parameter to false allows to create one's own PullPushAdapter (to invoke Receive).

 public void SetMethodLookup(MethodLookup lookup)

Allows to set a method resolution method which will be executed by the underlying MethodCall object to resolve the method. If not set, MethodCall's internal lookup method will be used.

 public synchronized void HoldRequests()

Every request received after this call will be stored in a queue instead of being invoked on the target object(s). Method ReleaseRequests will invoke all queued requests on the target object(s) and reset the queuing flag.

 public synchronized void ReleaseRequests()

Removes all requests from the queue, invokes them on the target object(s) and resets the queueing flag. After this call, no requests will be queued any more until a call to HoldRequests is made.

 public void AddFunclet(Object target,
                        String funclet_name,
                        Object funclet)

A funclet handles requests on behalf of the target object. All methods (MethodCalls) containing a non-empty funclet_name field will be handled by funclet instead of target. Both funclets and their methods need to be public, otherwise an IllegalAccessException will be thrown at runtime.

 public void AddTargetObject(Object target)

 public void RemoveTargetObject(Object target)

 public void RemoveAllTargetObjects()

 public synchronized void Receive(Message msg)

 public Serializable GetState()

 public void SetState(Serializable state)

 public static void main(String args[])

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