The validators are only used in the WebTools Entity Data Maintenance screens.
They are intentionally not used in other parts of the project as validation is
best in the logic layer, and not in the data layer (makes things far more
reusable and flexible).
I actually consider these to be a bad design from very early on in the project
when the entity engine was one of the only tools in the framework, and IMO it
would be better to remove them than to support them everywhere.
-David
On Jun 26, 2010, at 10:54 AM, Adrian Crum wrote:
> The entity engine allows you to specify field validators in two places: in
> the fieldtypeXxx.xml files and in the the entity definition.
>
> The validators in the fieldtype files are not used as far as I can tell.
>
> The validators in the entity definitions require complicated client code to
> use them - they are not used automatically by the entity engine.
>
> The bottom line is, specifying a validator in either location does absolutely
> nothing. I don't know if this was designed this way or not.
>
> I have a design in mind that I think will be better...
>
> 1. Create a validator interface that can be used throughout the project:
>
> public interface Validator {
> void isValid(Object obj;
> }
>
> The isValid method throws an IllegalArgumentException if the object is not
> valid.
>
> 2. Set up a library of commonly used validators and put them in a Validator
> factory. Modify ModelField and ModelFieldType so they load validators from
> the factory.
>
> 3. Have ModelField and ModelFieldType implement Validator. Those classes
> delegate the isValid method call to their contained validators.
>
> 4. Modify GenericEntity.set method to call the ModelField's isValid method.
>
> The advantages to this approach are:
>
> 1. Validators are reusable. The same validators could be used on service
> parameters for example.
> 2. Client code is shielded from validation details. Just call the isValid
> method.
> 3. OFBiz users can implement custom Validator implementations and add them to
> the Validator factory.
>
> What do you think?
>
> -Adrian
>
>
>
>
