Re: Abstract Entities [Was: Modelling improvements: inheritance + interfacing (Draft)]

From: Aristedes Maniatis (ar..aniatis.org)
Date: Wed May 30 2007 - 04:32:29 EDT

  • Next message: Andrus Adamchik: "Re: Abstract Entities [Was: Modelling improvements: inheritance + interfacing (Draft)]"

    On 29/05/2007, at 8:01 PM, Andrus Adamchik wrote:

    > Trying to decompose it further (so that we could Jira individual
    > chunks easily :-))... +1 for the abstract entities support, but
    > they can also be implemented as a separate feature independent from
    > inheritance per se.
    >
    >
    >> <obj-entity ...> needs the following additional (optional) xml
    >> attributes:
    >> - isAbstract="flag"
    >
    > +1
    >
    > Also the following steps will be needed:
    >
    > * Modeler checkbox for ObjEntity "abstract" flag

    Yes.

    > * Changes to the code generation templates to generate abstract
    > java classes for such entities

    Yes and the setIsAbstract() and getIsAbstract() functions for
    ObjEntity which go hand in hand.

    > * Changes to the validation rules to allow ObjEntity with no db
    > entity for abstract entities

    Actually I don't think that is needed for this first step. That is
    needed for step 2: horizontal inheritance.

    > * maybe also some runtime checks for abstract entity (???)

    I think the main one is that you cannot perform a SelectQuery (or
    anything else that returns an ObjEntity) on an abstract entity with
    no concrete subclasses. Kind of makes isAbstract a bit useless on its
    own, but it is a step in the right direction.

    Ari

    -------------------------->
    Aristedes Maniatis
    phone +61 2 9660 9700
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