Avoiding diamond shapes in Java when using composition and inheritance -


i've been building system has 5 classes, class containing main method initialize, show , modify various different objects aforementioned 5 classes. understand how use inheritance adopt fields in both therapist , patient classes person (e.g. name, address phonenumber fields) parent-class, , how use composition (at-least theoretically) build objects of consultation , bill patient class.

however, i'm confused on how should go storing field called therapist name in therapist class , showing when call object of patient. i've included class diagram on how think should like, apparently forms diamond big no-no in java. what's in class diagram work?

could show example of how store therapist name in therapist class , move data member on patient when create objects?

here's diagram:

link

the diamond problem doesn't exist java, because java support multiple inheritance of signature, not of implementation (though i'm not sure how works java 8 interface default methods -- haven't messed them thoroughly yet). diamond problem in multi-inheritance-of-implementation languages refers problem of 1 class inheriting same grandparent class through 2 different parent classes. in c++, instance, you'll either grandchild having 2 distinct grandparent instances (one per parent class), can 2 different results casting object grandparent, depending on parent cast comes from; or you'll have single grandparent instance, shared both parents -- might update grandparent using different semantics.

in case, if want add therapistname field patient, add field called therapistname , initialize either through constructor param or setter. there's no problem here.

bottom line: diamond pattern no-no multiple inheritance of implementation, java doesn't support (again, possibly excluding interface default methods). diamond caused composition isn't antipattern, nor cause pain, other perhaps making initialization and/or disposal logic more cumbersome.


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