Having a non BC Drop Down Select component with list items From BC Data Control. ADF 11g

Hi,

in this example we are going to  create an application where we will have a drop down list where it's value is going to be stored to a managed Bean.

The list Source is going to be from a Data Control that comes from Business Components.
Countries for example, from HR Schema.

The goal here is to demonstrate that is possible to have a list of Values component that belongs to "a" DataControl(in our case, we are using a ManagedBean) and uses a list of possible values from another DataControl(In our case, HR Schema, Countries View Object).

Download Sample Application.

NOTE: in this post, we are going to follow another approach of explaining things...
We are going to follow the first thing that it might come in mind. Then we are going to think it over and see the simplicity of things. This is an experimental way of approaching a matter and covers the case where things are not that clear in our mind regarding the best approach to follow. Sometimes I find people accepting solutions "as is" without considering to challenge them. With this approach, we are going to rethink some approaches in order to determine which is the simplest and best. Make sure that you read until the end. We are all busy and we want the solution fast. But, trust me, there is more into it than just accepting the solution.


The case scenario here is pretty simple:

One attribute,
Hold the value in a ManagedBean,
Get the List of Possible Values from a View Object.
We simply create the Business Components:

An Empty Page:

Then, we will have to create the Select One choice Component

From the component palette in JDeveloper, we locate the Select One Choice component and we drop it into the page we created previously.

When we drag and drop it into the page, JDeveloper will show a dialog that will require the following information:

The first screen, requests us to determine whether this Select One Choice will have a binded list or a static list.

And of course, the common properties, such as the value holder.

(Lets think out loud a bit here)
We are dropping a select one choice into a page..
Where is the value held?? uh.. in a managed bean.. (in the example at least..)
-really?? where is that??
-uh.. we have to create it??
-YES! But why did not we do it before dropping the component?
-uh... we did not think that we havent finished with the "model" part..
-Yes, we are used to the bindings and we thought that everything will be generated automatically... Here it is not the case.. Alright, lets create a java class..

-what about this wizard? The one of the Select One Choice?
-Cancel it..
-Are we forgetting something??
-no! it's cool.. We got this, it is the java class missing.. the bean..
-ok.. (dont hold your breath just yet...)

Great,
now?
-now... now, we will place the setter and the getter to the Select One Choice component...
-ok.. so? how are we going to do it?
-Simple, we will add #{javaClass.lovValue} in the value property of  the Select One Choice.
-Are not we  forgetting something?
-uh..... no..
-ok.. lets proceed then..
-oh wait a minute! we are working with JDeveloper! lets do it declaratively!!
-yes! lets go.

Lets drop the Select One Choice once more..
(The same  procedure again.. If only we had thought of this earlier.. We would have solved several wizards and clicks..... anyway)

So, after doing the same process again, we select the value and expression builder:

a closer look:

-where is it??
-where is what???
-The bean..
-what bean?
-the bean!! the managed bean!! the javaClass we created! where is the bean!!! (oh... JDeveloper and it's wizards.. Declarative development they say.... what do they know.... I will put the EL on my own and everybody is going to be happy..

-Good.
-Uh.. I think we forgot something here...
- No we did not..
-Are you sure??
-yes yes.. We got this..
-ok... (....)
-press finish..

-It kind of looks weird.. Does not it?
-What do you mean?
-The Value has errors.. It is strange... maybe it something from the IDE wrong.. (As usual... somebody else's fault)

-WELL, it is not actually strange.... (do you remember inversion of control??)
-oooh... we have to set up the managed Bean... I totally forgot  about that!
-it happens..
-well actually, I was confused because with JDeveloper wizards produces everything by default when making actionListeners and valueChangeListeners...

-well yes.. but we should not forget the basic principals.. dont you think?

OK after setting the managed Beans:

There is no more errors, plus, we are able to see the bean in the wizard.. (Wizards, do know in the end.. )

OK.. everything seems to be ok..
-Lets Run The Page!!!!!

-are we ok with everything??
-yes yes!!
-Maybe it would be better to do a small recap before deploying and running the application..
-Lets see,

• Generate BC: done.
• Create java Class: done.
• Declare it as a Managed Bean: done.
• Drop the SOC into the page: done.
• Map the Selected Items: OMG!!! we totally forgot about that!!!!!!! OMG! OMG!
• map the value property:done..

-Ok.. Ok.. what do we do now? Do we drag and drop the SOC again? Do we do it everything from the beginning??

-no.

-But it is easier..

-yes. But we have to learn how to fix things..

-.....

lets open the page with and see the source code of the SOC (in the page select source tab):

What do we see here?
-We see that the select items is empty.. This is quite correct since, we, forgot to finish the JDeveloper wizard with all the needed values properly.
So, we have to do it manually now..

We have to know how to do it manually as well, simply because we have to. Wizards are good, but we really need to know what actually happens.

Ok. here is what we have to do:

• Create a page Definition
• Add a list in the page Definition
• update the code of the SOC in the jspx

ok, the page Definition creation is very easy"
right click on the page and then  select Go To page Definition.. JDeveloper will tell you that there is no page Definition and will ask whether to create it or not. Create it of course. After that, we have an empty page Definition:

 Then, we have to add the list:

 Select the last option. All other options do not suit us, simply because, we do not navigate, we do not have any other Base Data Source to update:

After pressing ok, we have to declare the iterator that will fetch the list of values for this SOC:

 Then , we have to select a Display Attribute.
 The value of this attribute will be shown in the SOC. This is the value the user will see.

Press ok and we are done with the creation of the list. the pageDefintion code is now updated with the following:

Ok.
All we have to do now is to update the SOC with this list.
We locate the jspx and we view the source code. We locate the SOC and we change the value property of the f:selectItems components to:



For those of you rushing to say that there is no items property in the SOC. Look closer. 
The select items is a separate component. Further more, here is a screen with the declarative way:

Finally, we are done:

Download Sample Application.

Regards.