Input Extensions – DropDowns

Many thanks to long-time reader and Oracle Policy Automation expert Aaron H for an interesting discussion just before the holiday season. The subject for this post is as you can tell, Input extensions that are dropdowns.

Our conversation was wide ranging but this article will focus on a couple of things

  1. How to ensure that the extension displays and handles the text and value elements of your list of values
  2. How to handle <uncertain>
  3. How to have a different label for <uncertain>

Along the way this will give us the opportunity to understand the usefulness of the Value() function in a rule. In later posts in this series we will look at other forms of Input, also beyond the basic INPUT or SELECT tag.

So let’s begin with a simple setup – the Zip Archive is available in the OPA Hub Shop by the way) – starting with just one attribute and a Value List:

The initial Value List looks like this – notice that in this case, there is no distinction between the displayed text and the actual value:

Input Extensions - DropDowns

In this simple scenario, one often sees extension code that focuses on the control.getOptions() method and then iterating through the various options from the returned object, something a little like this (for educational purposes only) :

var myChoices = control.getOptions();
for (key in myChoices) {
if(myChoices[key].value)
{
$('#xDropDown').append('<option value="' + myChoices[key]..text.toString() + '">' + myChoices[key].text.toString() + '</option>');
}
}

The code works fine, but makes a few assumptions that can come back and bite later when the rule designer has made changes.

  1. It does not take into account the possible change in the Value List to include display and values.
  2. It will error out if the dropdown becomes non-mandatory since “uncertain” will cause .toString() to fail

So when the developer of the rule changes the Value List to something like this:

Input Extensions - DropDowns 2

The code would no longer be useful since the [key].text and [key].value are two different values. And if we are updating the underlying control, we need to remember that we call control.setValue() so it is expecting a value, not the display value.

So maybe the code gets changed to :

 $('#xDropDown').append('<option value="' + myChoices[key].value + '">' + myChoices[key].text.toString() + '</option>');

Or something similar. All is well and the dropdown is correctly handling things :

Until the attribute is defined as non-mandatory in the Screen where it is displayed. At which point the code breaks again, as the uncertain value is not handled. Let’s take a step back and remind ourselves of the defaut behaviour in these situations, without an extension:

The standard control renders an empty option for the uncertain value. I’ve always considered it a bit of a bug that it does not respect the optional Display Value (in my case, “Not Sure” – see the screenshot a little further up) but always renders a blank, at least in all my browsers.

So in the case of an Input Extension that needs to render the uncertain value (because the control is not mandatory) and also wants to show the Display Value, the code will probably need to have another quick change:

Input Extensions DropDown Code Last One

Which will ensure that the dropdown is rendered with the correct text and value, if there is one. Also, the added bonus is that the display text of uncertain is rendered as we would expect:

Input Extension Showing Uncertain Vlaue

And finally, we have good use of the Value() function so that we can be sure that the correct value is stored in our Interview:

The function above, in a Word document for example, will return the value rather than the display value. So you can drop it onto the final Screen of your testing Project and compare the two to make sure you have gathered the correct one.

Hopefully that was fun and interesting, and you can practice yourself with your own project. As mentioned above the code is available in the OPA Hub Shop. The documentation is of course on the Oracle Intelligent Advisor website.