[rules-users] Find out order of insert in RHS

[Sandjaja, Dominik]

Hi everybody,

short: is there a way to have an automatic counter for the RHS of a rule when inserting several objects in one rule?

Long:
I use drools with a DSL to insert items for a frontend dropdown box. The generated rule is e.g. like the following one:

    rule "testRule_H"
        dialect "mvel"
            when
                SomePartOfMyModel( someField == "H" )
                    then
                        DropDownItem fact1 = new DropDownItem(); fact1.setLabel( "My Label 1" ); fact1.setValue( "B" );
                                                                       insert (fact1);
                        DropDownItem fact1 = new DropDownItem(); fact1.setLabel( "My Label 2" ); fact1.setValue( "A" );
                                                                       insert (fact1);

This works nicely and I get all the items. The problem I have is with the sorting. Users use Guvnor to edit the available items for the dropdown box, so they add and remove items from the RHS. Since I retrieve those objects from the knowledge base in my java code like this:

Collection<FactHandle> handles = statefulKnowledgeSession.getFactHandles(new ClassObjectFilter(DropDownItem.class));
        for (FactHandle handle : handles) {
            DropDownItem selectItem = (DropDownItem) statefulKnowledgeSession.getObject(handle);
            ...

I think I cannot be sure about the order the objects are retrieved (it's a collection, no guaranteed sorting!). So, I sort the DropDownItems alphabetically by their value.

My question now is, as stated above: How can I implement a counter which I can use in the facts being inserted to keep my inserted facts (DropDownItems) in the same order as they are inserted?

Thanks in advance
Dominik

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mit freundlichen Grüßen / kind regards
Dominik Sandjaja
Fon: +49 (0) 203 60878 183
Fax: +49 (0) 203 60878 222
e-mail: dominik.sandjaja at it-motive.de

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