Creating dynamic datasources. Is this possible?

Question

Can I create a 'subset datasource' from an existing datasource
and then pass this subset datasource to the <jbo:RowsetIterate>
Let's assume I have a datasource containing 100 records.
How is is possible to create a new datasource from the exiting datasource
which will contain 10 records and then this new data source will be passed
to <jbo:RowsetIterate>?
I'd like to write a JSP Tag which reads the datasource and creates a subset datasource
dynamically
public class SubsetDS extends TagSupport
     public int doStartTag() throws JspException
        ApplicationModule am  = dataSource.getApplicationModule();
        ViewObject vo = am.findViewObject("V0");  
         while(vo.hasNext()){
        Row r = vo.next();
               // Iterate based on a certain condition and put the new records
        // in a dynamically created DataSource
Is this possible?

Answer 1

I don't know about the custom JSP tag part, there is a <jbo:CreateViewObject> tag and ApplicationModule.createViewObject() methods for defining ViewObjects at runtime. We were not able to locate a mechanism for actually running a query against one VO to select rows for a second VO (whether defined at compile-time or runtime). We created a VO at runtime so we could base it's result set on another VO.
See "Ways to Add a View Object Instance to the Data Model at Runtime" topic in JDev help (we're using 10.1.2, but there's a <jbo:CreateViewObject> tag going back to at least 9.0.3.3); I located using JDev's Help's text search for createviewobject.
In our case, because the two queries were related (subset), we obtained the where clause from the VO that we defined at compile-time and whose where clause is being set at run time by values passed in from an HTML query form. We then applied that where clause to the dynamically created VO to get the desired subset.
Hope that gives you a starting place and helps.