Dependent Dynamic message choicelists

This is one of the most common scenario in any web application page.Basically here i am just giving an idea how to code for dependent message choicelists in OA Framework page both at page level or in a collective ui feature like table or hgrid.

3 Message Choicelists in a Page :

Lets consider the first scenario, where we have 3 dependent message choicelists(mc1,mc2,mc3), these can be n in number, just follow the same approach.Here mc1,mc2 and mc3 are the item ids of the message choice lists in the page UIX file, which are attached to vo instances mc1VO1 and mc2VO1 and mc3vo1 respectively.Assuming "Intial value" property value is blank and "Add blank value" is "true" in property inspector for all three poplists.
Lets start from controller code, please read comments, as they explain each and every line..

Controller Code

/*Code in Controller*/
import oracle.apps.fnd.framework.webui.beans.message.OAMessageChoiceBean;

//Code in process request
OAMessageChoiceBean mc1 = (OAMessageChoiceBean)webBean.findChildRecursive("mc1");
/*The poplist data object that OA Framework creates the first
* time is cached in the JVM and reused
*until you explicitly disable caching
*Hence, use setPickListCacheEnabled API to stop JVM
* from caching Poplist values, this API needs to be called on any Poplist
* where the VO where clause keeps on changing
*/
mc1.setPickListCacheEnabled(false);
//Similarly for second Poplist
OAMessageChoiceBean mc2 = (OAMessageChoiceBean)webBean.findChildRecursive("mc1");
mc2.setPickListCacheEnabled(false);

//Similarly for third Poplist
OAMessageChoiceBean mc3 = (OAMessageChoiceBean)webBean.findChildRecursive("mc3");
mc3.setPickListCacheEnabled(false);

//Code in process form request
/*If a value is selected in mc1
*"update" is the name of PPR event
* attached to poplist mc1
*/
if("update".equals(pageContext.getParamete(OAWebBeanConstants.EVENT_PARAM))) {
String value_selected=pageContext.getParameter("mc1");
//Priniting the value selected
System.out.println("value_selected in mc1>>"+value_selected);
//if the selected value is not null
if(!(("".equals(value_selected)) (value_selected==null)))
{
//then calling the method in AM which will reinitialise VO query
// in second message choicelist and not third because
//the value selected in seocond will null
//as we have turned Add blank value to true
//and initial value is null in property inspector
Serializable[] param = {value_selected};
am.invokeMethod("initmc2VOQuery", param);
// if user selects some value in first choicelist
// pass some dummy_value in mc3vo query so that it returns 0 records
//or you can put some condition in vo query like where 5=6
Serializable[] param = {dummy_value};
am.invokeMethod("initmc3VOQuery", param);
}
else
{
// if user selects null in first choicelist
// pass some dummy_value in mc2vo query so that it returns 0 records
//or you can put some condition in vo query like where 5=6
//doing this for mc2vo1 and mc3vo1
Serializable[] param = {dummy_value};
am.invokeMethod("initmc2VOQuery", param);
am.invokeMethod("initmc3VOQuery", param);
}
}

/*If a value is selected in mc2
*"update1" is the name of PPR event
* attached to poplist mc2
*/
if("update1".equals(pageContext.getParamet(OAWebBeanConstants.EVENT_PARAM)))
{
String value_selected=pageContext.getParameter("mc2");
//Priniting the value selected
System.out.println("value_selected in mc2>>"+value_selected);
//if the selected value is not null
if(!(("".equals(value_selected)) (value_selected==null)))
{
//then calling the method in AM which will reinitialise VO query
// in third message choicelist
Serializable[] param = {value_selected};
am.invokeMethod("initmc3VOQuery", param);
}
else
{
// if user selects null in second choicelist
// pass some dummy_value in mc3vo query so that it returns 0 records
//or you can put some condition in vo query like where 5=6
//doing this only for mc3vo1
Serializable[] param = {dummy_value};
am.invokeMethod("initmc3VOQuery", param);
}
}

Dependent message choicelists in Table

Controller Code :

/*Cosider two message choicelist items HeaderPoplistItem and LinePoplistItem in table with item id "XXX".We will use setListVOBoundContainerColumn api,which is typically used for containers that repeat it's content multiple times and want to attach different set of records for each iteration, eg table or hgrid.*/

OATableBean XXX = (OATableBean)webBean.findChildRecursive("XXX");

/*LinePoplistItem is a poplist item, in which view def is filled and not view instance this is based on initial value in HeaderPoplistItem which is a poplistwith view instance name*/
OAMessageChoiceBean LinePoplistItem = (OAMessageChoiceBean)XXX.findChildRecursive("LinePoplistItem");
//
LinePoplistItem.setListVOBoundContainerColumn(0, XXX,"HeaderPoplistItem");


AM code
//Also note for runtime dependency of table of hgrid poplists, you have attach PPR in the LinePoplistItem and in your event method in AM write:
getVO().setWhereClauseParam(0,);
getVO().executeQuery();

In this article , i have covered the Dependent Dynamic message choicelists in tables and independent poplists on page. Hope this scenario is now clear.