Rational Developer for System z

Evaluating a screen description

A screen description matches the currently displayed application screen if all of the descriptors contained in the screen description are true.

The host editor uses the following procedure to determine whether a particular screen description matches the currently displayed application screen:

  1. The host editor begins evaluating each descriptor in the screen description, starting with the first descriptor and working through sequentially towards the last descriptor.

  2. For each individual descriptor that the host editor evaluates:
    1. First the host editor determines whether the descriptor, based on its type and on the values of the properties it contains, is true or false with respect to the currently displayed application screen. For example, if the descriptor is a String descriptor and states that the application screen has the text string "OPERATOR INSTRUCTIONS" at row 1, column 11, and if in fact the application screen does have that text string at that location, then the host editor determines that the descriptor is true. Otherwise, the host editor determines that the descriptor is false. (See Working with screen descriptors.)
    2. Then the host editor checks the Invert Match property of the descriptor. If the Invert Match property is set to true, then the service flow inverts the Boolean result obtained in the previous step, converting true to false or false to true.
    3. If the Boolean result that the host editor has obtained at this point is false, then the host editor immediately stops evaluating the descriptors of this screen description and deems that this screen description does not match the currently displayed application screen.

  3. If the host editor finally evaluates all the descriptors contained in the screen description and obtains a result of true for each one, then the host editor deems that the screen description does match the currently displayed application screen.


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