Asynchronous Behavior › Async Action Statements › USE ASYNC › Examples

Examples

The Action Diagram of the Toolset helps construct the USE ASYNC statement. The following examples show the various types of USE ASYNC:

• An asynchronous request indicating that the application does not wish to receive the response associated with the request:

  +--USE ASYNC target_pstep (Procedure Step)
  | WHICH IMPORTS: ...
  | IDENTIFIED BY: viewname async_request
  | RESPONSE HANDLING: NO RESPONSE
  +--WHEN request accepted
  +--WHEN request not accepted
  +--
  

• An asynchronous request indicating that the application wishes to Poll for the response, where the response is only available to the PStep initiating the request:

  +--USE ASYNC target_pstep (Procedure Step)
  | WHICH IMPORTS: ...
  | IDENTIFIED BY: viewname async_request
  | RESPONSE HANDLING: POLL
  | RESPONSE SCOPE: PSTEP
  +--WHEN request accepted
  +--WHEN request not accepted
  +--
  

• An asynchronous request indicating that the application wishes to Poll for the response, where the response is available to other processing executing within the process:

  +--USE ASYNC target_pstep (Procedure Step)
  | WHICH IMPORTS: ...
  | IDENTIFIED BY: viewname async_request
  | RESPONSE HANDLING: POLL
  | RESPONSE SCOPE: GLOBAL
  +--WHEN request accepted
  +--WHEN request not accepted
  +--
  

• An asynchronous request indicating that the GUI application wishes to be notified when the response becomes available to be obtained from the runtime. Additionally, this request indicates that the response is available only to the PStep that initiated the request.

  +---USE ASYNC target_pstep (Procedure Step)
  |    WHICH IMPORTS: ...
  |    IDENTIFIED BY: viewname async_request
  |    RESPONSE HANDLING: NOTIFY EVENT
  |    RESPONSE EVENT: eventname
  |    RESPONSE SCOPE: PSTEP
  +  WHEN request accepted
  +  WHEN request not accepted
  +---
  

• This example also shows the EVENT ACTION block that is created when the USE ASYNC statement was created. The name of the EVENT ACTION is automatically assigned to be the same as the target_pstep referenced on the USE ASYNC statement. If the application developer wishes to create a new EVENT ACTION (as opposed to using a previously defined EVENT ACTION) and if for some reason an EVENT ACTION already exists with the target-pstep name, the Toolset will create a unique name for the new EVENT ACTION (for example, adding a 1, 2, 3, and so on).

  +--USE ASYNC target_pstep (Procedure Step)
  | WHICH IMPORTS: ...
  | IDENTIFIED BY: viewname ASYNC_REQUEST
  | RESPONSE HANDLING: NOTIFY EVENT
  | RESPONSE EVENT: target_pstep
  | RESPONSE SCOPE: PSTEP
  +--WHEN request accepted
  +--WHEN request not accepted
  +--
  .
  .
  .
  +--EVENT ACTION target_pstep
  |
  +--
  

• An asynchronous request indicating that the application wishes to be notified when the response becomes available to be obtained from the runtime. Additionally, this request indicates that the response is available to other processing that is executing within the process:

  +--USE ASYNC target_pstep (Procedure Step)
  | WHICH IMPORTS: ...
  | IDENTIFIED BY: viewname ASYNC_REQUEST
  | RESPONSE HANDLING: NOTIFY EVENT
  | RESPONSE EVENT: target_pstep
  | RESPONSE SCOPE: GLOBAL
  +--WHEN request accepted
  +--WHEN request not accepted
  +--
  .
  .
  .
  +--EVENT ACTION target_pstep
  |
  +--