Inconsistent use of clearing collections in case of update methods.

[sjaakd]

when using ADDER_PREFERRED the following update method is generated:

    @Override
    public Car updateCar(CarDto dto, Car car) {
        ...
        if ( dto.getPersons() != null ) {
            for ( PersonDto person : dto.getPersons() ) {
                car.addPerson( dtoToPerson( person ) );
            }
        }
       ...

It doesn't clear the collection. This is not consistent with other CollectionMappingStrategie's
icw update methods.

[jklapwijk]

Will the collection.clear() be added to the generated update method implementation for the ADDER_PREFERRED strategy?

[sjaakd]

I'm reiterating some issues.. I see there's a difference. Although I am thinking whether we should access a getter when handling an adder method... @filiphr : WDYT?

[filiphr]

This is a tough one @sjaakd. I also had the same question last week. I would say if you are using an adder strategy we should not touch the getter. It might even be possible that the adder returns an immutable collection that will throw an exception if we clear it, so I wouldn't go there 😄

[sjaakd]

Ok.. I'll close this one.. But we clear collections also in the regular case. Should we leave that as is?

[filiphr]

I think that in the regular case it is OK. The reason is that we are using the getter to add to the collection, so we can clear it. If we can't clear it we also can't add to it (at least that is my reasoning)

[sjaakd]

Agreed. But do we add this reasoning somewhere..? FAQ?

[filiphr]

Perhaps in the documentation?

[sjaakd]

Good idea.. I'll open op a pr for that..

[filiphr]

In Update existing bean instances

we currently have

Collection- or map-typed properties of the target bean to be updated will be cleared and then populated with the values from the corresponding source collection or map.

Maybe we need to add about the adders here

[sjaakd]

Maybe we need to add about the adders here

Hmmm. Immutable? I don't think we have adders for maps..