Supply functions in WebDynpro

[Former Member]

Imagine a purely abstract situation. You are displaying a list of your customers, received by calling BAPI_CUSTOMER_GETLIST function module. On the list you want to have a special column containing a checkbox which is checked if customers phone number is the same as their fax number.

The first thing one does is creating an adaptive RFC model. After that, the next obvious thing to do is bind the Context of the Controller to the Model. The Context of the Controller looks like this:

The next obvious thing to do is to bind view Context with the Controller's and apply table template to the view. But it is not so easy. The BAPI does not provide explicit information whether the phone and fax numbers are identical. You can of course write your own function module wrapping the BAPI and providing the required data or extend the BAPI. Still, you probably won't get more than a TextView inside the table displaying either "X" or a space. Why only TextView - because of the data type that CheckBox requires for the "checked" property. BAPI return tables are converted into set of Strings, and CheckBox requires bindery of boolean node attribute.

The answer for this case is to extend the Context node with some extra nodes/attributes of correct type and fill them with data after executing the RFC Model. The extended Context (it is best to do it inside the Controller) could look this:

The next thing to do is to set properties of the newly created attribute and node

attribute properties:

node properties:

Some explanations

cardinality	1..1 guarantees that there is always one and only one element in the node for one parent element
singleton	false - there is a new Object for each parent node, so once the values are supplied by a supply function for a given parent element, the supply function is not called anymore. This way they can be modified and don't get overwritten

Now you can add a CheckBox to the table and bind the "booleanAttribute" to the CheckBox's "checked" property. But it won't work yet. The final step is to implement the supply function. In our case the source would look like this

public void supplySpecialParameters(IPrivateSupplyTest.ISpecialParametersNode node, IPrivateSupplyTest.IAddressdataElement parentElement){  //@@begin supplySpecialParameters(IWDNode,IWDNodeElement) ISpecialParametersElement elem = node.createSpecialParametersElement(); node.bind(elem); elem.setBooleanAttribute(  parentElement.getFax_Number().equals(   parentElement.getTel1_Numbr()));  //@@end}

The supply function is called every time a data for the node was not yet supplied for the parent node. If the node is a Singleton node the function is called every time parent node's lead selection changes.

Now, you can try to connect all pieces together. If you have little experience in WebDynpro look on the blogs. There are many interesting courses for beginners - ie. Table Handling in WebDynpro by Harsh Chawla would be useful here.

Try to experiment more too - by giving the additional value node other type than boolean - for example Visibility - you could control display parameters of the View. Imagine that you can create a View that can be used as an edit and view form just by changing the readOnly and Visible properties for InputField and Button - and have it's behavior controlled by just a single "X" in the function module output.