Batch-mode Event Support

OpenEdge running in batch mode supports the following events:

There are ten miscellaneous events (U1 to U10 developer events) that have no standard meaning or action. They are reserved for an ABL developer to use for associating a trigger with some event that only happens programmatically using the APPLY ABL statement, and which has nothing to do with a particular user action. These developer events have no built-in significance. There is also the CLOSE event which has these same characteristics. The CLOSE event only occurs when you specify it with the APPLY statement in your application.

You can use developer events or CLOSE in your application when running an OpenEdge client in batch mode. This means an application can execute the WAIT-FOR ABL statement with a developer or CLOSE event in batch mode. Similarly, you can specify ON "U1" OF or ON "CLOSE" OF an object and then programmatically APPLY "U1" to the object to execute the code. There is no change in how OpenEdge process these events. That is, OpenEdge clients running in batch mode process these events just like non-batch clients do.

An example of when using developer events in batch mode could be useful is when you have an application that works with ABL sockets, asynchronous AppServer requests, or asynchronous state-free AppServer requests. For instance, an application might spawn several asynchronous AppServer requests, and use one or more developer events to determine when all requests completed, as opposed to using the PROCEDURE-COMPLETE event in a loop until all requests complete. If working with a state-free AppServer, the application will get the response to the asynchronous requests out of order and you can use these developer events to better handle these situations.