provided.client.model

Interface IClientModel

public interface IClientModel

This interface is provided as a guide for building the client-side model. This interface is not in any way fundamental to the operation of RMI, though the behaviors described here are critical to proper RMI operation.

The behaviors as described here are REQUIRED for any client implementation though the use of this particular interface is not.

Suggestion: Copy this interface to one's own code to use as a starting point and then modify it to suit one's specific needs.

Discussion point: Notice that this interface is completely decoupled from the notion of ITaskFactory's. Should this model work with factories or with the tasks directly? In the past, many people have had their models work with the factories. But some people have argued that the factory operations, e.g. creating a new factory, combining factories and even getting the product of the factory are completely separate, decoupled operations from the rest of the model and thus should be encapsulated separately. What do YOU believe?

Author:

Stephen Wong

Method Summary

Modifier and Type	Method and Description
java.lang.String	connectTo(java.lang.String remoteHost) Connects to the given remote host's Registry and retrieves the stub to the ICompute object bound to the ICompute.BOUND_NAME name in the remote Registry on port IRMI_Defs.REGISTRY_PORT.
<T> java.lang.String	runTask(ITask<T> task) Runs the given ITask on the remote engine server, returning the String formatted result, which is produced using the given ITask's ITaskResultFormatter object.
void	sendMsgToComputeEngine(java.lang.String text) Sends a string message to the connected compute engine using the IRemoteTaskViewAdapter STUB received from the engine server.
void	start() Starts the client model by initializing the RMI system and creating a remote view adapter stub for use by an engine server.
void	stop() Stops the client model by using the IRMIUtils to stop the RMI system.

Method Detail

start

void start()

Starts the client model by initializing the RMI system and creating a remote view adapter stub for use by an engine server. Procedure:
1. (DO THIS FIRST!) Use the IRMIUtils to start the RMI system, using port = IRMI_Defs.CLASS_SERVER_PORT_CLIENT. This will also automatically start the the security manager and the class file server for remote dynamic class loading.
2. Export a STUB from the client's IRemoteTaskViewAdapter RMI server object. Save this stub for use when connecting to an engine server.

stop

void stop()

Stops the client model by using the IRMIUtils to stop the RMI system. This automatically stops class file server. This MUST be called before exiting the system!

connectTo

java.lang.String connectTo(java.lang.String remoteHost)

Connects to the given remote host's Registry and retrieves the stub to the ICompute object bound to the ICompute.BOUND_NAME name in the remote Registry on port IRMI_Defs.REGISTRY_PORT. Procedure:
1. Use the IRMIUtils to retrieve the remote Registry at the given IP address.
2. Use the remote Registry to retrieve an ICompute STUB bound to the name defined by IComputer.BOUND_NAME Save the reference to the IComputer stub somewhere.
3. Use the ICompute stub to give the client's IRemoteTaskViewAdapter STUB to the remote engine server and retrieve the compute engine's IRemoteTaskViewAdapter stub. Save the retrieved stub for later use. Use the retrieved stub to send a connection status message to the remote compute engine's user interface.
4. Return a string indicating the success or failure of the connection attempt.

Parameters:

remoteHost - The IP address or host name of the remote server.

Returns:

A status string on the connection.

sendMsgToComputeEngine

void sendMsgToComputeEngine(java.lang.String text)

Sends a string message to the connected compute engine using the IRemoteTaskViewAdapter STUB received from the engine server. This message should also be echoed to the local user interface.

Parameters:

text - The message to be sent

runTask

<T> java.lang.String runTask(ITask<T> task)

Runs the given ITask on the remote engine server, returning the String formatted result, which is produced using the given ITask's ITaskResultFormatter object.

Type Parameters:

T - The return type of the give ITask

Parameters:

task - The task to run on the remote engine server.

Returns:

A string representation of the task results, using the task's formatter object.