trigger critic check actual stereotyp singleton accept singleton check attribut type singleton hold instanc singleton creat param dm link java lang object object check critic param dsgr link argouml cognit design design creat model us futur develop argo uml link problem problem critic trigger link problem problem predic object dm design dsgr look class model facad dm problem look singleton model facad singleton dm problem iter oper model facad oper dm iter oper object oper model facad constructor model facad problem problem 