Example: Implementing LU Support

The following examples illustrate implementing LU support with both task beans and task files.

Task Bean Example

Task beans implement the ITask interface. The instance name is a property on com.attachmate.tasks.ITask. When a request comes in from a client, the following occurs:

• The client is identified.
• The client is associated with an LU name or terminal ID.
• ITask.InstanceName is set.
• The task is executed.

To indicate to the run-time engine that the instance name refers to an LU name, the instance name must be formatted as follows: 

LU.<LU name>[,free] (IBM) 

-or->

ID.<ID name>[,free] (Unisys)

Where <LU name> or <ID name> is the name of the LU or terminal or station ID that you want to use, and "free" is an optional parameter that tells the Runtime Service to destroy the session instead of returning it to the pool.

The following code snippet illustrates how the code for task beans might look:

    ITask task = new MyTask();
    . . .
    task.setInstanceName("LU." + clientToLuMapping.getProperty(clientName, defaultLU));
    task.executeSync();
    . . .

Where

• clientToLuMapping is a previously initialized properties object that maps clients to LUs.
• clientName is the name or ID of the remote client making the request.
• defaultLU is a default LU name to use if no mapping exists for the client in question.

Task File Example

Task files are XML task interface objects that implement the IConnectorAccess interface (com.attachmate.connectors.screen.ScreenConnectorAccessImpl). They work similarly to task beans, except that the instance name is specified in IConnectorAccess.open. The instance name is appended to the file specification or URL using the URL query syntax, as follows:

<task file>?instance=LU.<LU name>[,free] (IBM)

-or-

<task file>?instance=ID.<ID name>[,free] (Unisys)

Where <task file> is the name of the task file to open and <LU name> or <ID name> is the name of the LU or terminal ID that you want to use. "Free" is an optional parameter that tells the Runtime Service to destroy the session instead of returning it to the pool.

The following code snippet illustrates how the code for ScreenConnectorAccessImpl might look:

    IConnectorAccess conn = new ScreenConnectorAccessImpl();
    . . .
    conn.open(taskFile + "?instance=LU." + clientToLuMapping.getProperty(clientName, defaultLU));
    conn.execute(taskName, inputParameters);
    . . .

Where

• taskFile is the file name or URL where the task metadata is located.
• clientToLuMapping is a previously initialized properties object that maps clients to LUs.
• clientName is the name or ID of the remote client making the request.
• defaultLU is a default LU name to use if no mapping exists for the client in question.
• taskName is the name of the task to run.
• inputParameters is the XML document containing the parameters for the specified task.
  

	Using Dedicated Sessions, Overview
	Creating Session Pools for Dedicated LUs