assemble dto using additional rules

[alexei1volf]

Hello. We are using geda-genericdto to make our life a bit easier. And we adjusted it for assembling with rules. We added possibility to skip data flow and to set default value (for dataPipe and for virtualDataPipe). May be it is out of scope, but it may seem interesting for you...

[denyspavlov]

Hi,

I think you got some cool ideas here.
And I am genuinely pleased to see this pull request.

Couple of suggestions I would give on this though.

DataPipeFlowRule is not single purpose class, which means that if you need more rules you need to modify it every time. I would rather have two interfaces RuleSet with single method apply and a Rule with isApplicable and apply:

interface RuleSet {

  void apply(Pipe pipe)

}

interface Rule {

   boolean isApplicable(Pipe pipe);

   void apply(Pipe pipe);

}

Then I would have the following logic in the assembleDto() method:

for (Pipe pipe : pipes) {
   ruleset.apply(pipe);
}

so clean an simple process with no "instanceof" or specific checks.

However that means if we do not have a ruleset at all then nothing would happen. So there should be a default RuleSet impl that does the current logic and allows to "plug in" custom rules:

class DefaultRuleSet {

   private Rule[] rules;

   DefaultRuleSet(Rule[] rules) {
       this.rules = rules;
   }

   void apply(Pipe pipe) {

        for (Rule rule : rules) {
            if (rule.isApplicable(pipe)) {
                 rule.apply(pipe);
                 return; // not sure if it makes sense to quit on first applicable rule but it is an option
            }
        }
        // if we are here then no rule fired, so do default write
       pipe.writeFromEntityToDto(entity, dto, converters, resolveBeanFactory(dtoBeanFactory));

   }

}

This way you can create various rules like SkipRule, DefaultValueOnNullRule, LogSecureDataAccessRule etc.

Above code is just quick and dirty pseudo code, but hope you get the idea.

Let me know if this was helpful.

Regards,
Denys

[alexei1volf]

Thanks for you suggestion, I got the idea and I like it.