CODEWITHSUNDEEP
umlsequence-diagramvisual-paradigm
Friedrich
Friedrich

Reputation: 123

UML sequence diagram, call

Let's say we have three classes A, B and C, and an instance a (resp. b/c) of type A (resp. B/C). Suppose that b is an attribute of a and c is an attribute of b.

In a method of a, the following is called : b.c.operation()

How can we represent this in a sequence diagram ?

Upvotes: 2

Views: 1164

Answers (3)

Peng Xiao
Peng Xiao

Reputation: 11892

Is this something you are looking for? You can try it out at https://www.zenuml.com.

enter image description here

Upvotes: 1

user9151377
user9151377

Reputation:

In programming it is not good to have b.c.operation()

All data should be hidden (should be private) in the class.

But if we have b.c.operation() , in the compiler it changes to (b.c).operation() so your code is equal to this code:

t=b.c;
t.operation();

Upvotes: 1

Brishna Batool
Brishna Batool

Reputation: 455

According to the Law of Demeter, an object should only communicate directly with its own neighbours. So in your case, a should not be calling b.c.operation() at all, as c is not a's neighbour. Rather, class B should provide an interface for this purpose, such as doCOperation(){c.operation();} and this is what a should call.

So the sequence of operations beocomes:

  1. a calls b.doCOperation()
  2. b calls c.Operation() within doCOperation() and returns the result to a.

Have a go at the sequence diagram now and it should be much easier.

Upvotes: 4

Related Questions