uml. frame: box around part of diagram to indicate if or loop if -> (opt) [condition] if/else -> (alt) [condition], separated by horizontal dashed line loop -> (loop) [condition or items to loop over] In this example: For each of the line item […] B->A: Hello. How can I represent this nested if else statement in a UML sequence diagram? I asked what one of them was and was told that's how an if statement is shown in a sequence diagram. The above sequence diagram contains lifeline notations and notation of various messages used in a sequence diagram such as a create, reply, asynchronous message, etc. 2)For a "when case", I would create a ConditionalNode with a Cause for each case as depicted below. B->A: Hi. First of all, […] Sequence diagram example. ... • Sequence diagrams are language-agnostic (can be implemented in many different languages) The second Clause represents the else execution. It also models the if-then-else logic in the sequence diagram. 3)In order to specify if the first iteration is made before or after a first evaluation of the test, I will use the boolean property named "tested first" available on LoopNode element. An alternative combined fragment is used to specify an area of a group of lifelines/ actors to show conditional flow in a sequence diagram. 3.change the "seq CombinedFragment1 " to "alt CombinedFragment1 "4.select the "Interaction Operand" 5.left-click at the "atl CombinedFragment1 ",you will found the one "InteractionOperand1" added into the "alt CombinedFragment1 ". There is no way to restore the lifeline at that point in the diagram as the activate keyword applies to the last message even if it is in different alt / else box. • A ref frame that names the other diagram. Treat sequence diagrams as a visualization of how objects interact rather than as a way of modeling control logic. That said, here’s the notation to use. In this page, we will demonstrate how to draw a simple sequence diagram with applying alternative combined fragment. You can edit this UML Sequence Diagram using Creately diagramming tool and include in your report/presentation/website. You'll notice B remains deactivated (without a lifeline) after the else statement. 1.create a sequence diagram. if the percentage is above 90, assign grade A; if the percentage is above 75, assign grade B; if … This is a sequence diagram that shows the representation of selection and loop. 460 2 2 silver badges 13 13 bronze badges. In a sequence diagram, iteration and branching are also used. Figure 4.4 shows a simple algorithm based on the following pseudocode: Or is a communication diagram better in this case? UML Activity Diagrams and UML Interaction Overview Diagrams are more expressive when it comes to showing complex flow with decisions etc. activate B. alt. share | improve this question | follow | asked Apr 21 '19 at 8:19. llamaro25 llamaro25. In computer programming, we use the if statement to run a block code only when a certain condition is met.. For example, assigning grades (A, B, C) based on marks obtained by a student. [else] Linking sequence diagrams 14 • If one sequence diagram is too large or refers to another diagram: • An unfinished arrow and comment. I went on an interview last year and was shown a sequence diagram and was asked to describe the the sequence. 2.add a CombinedFragment1 into diagram. There were 2 things in the diagram I had never seen before. Dig uml-diagrams.org for explanations and examples – xmojmr Mar 20 '15 at 7:42 Is it possible to do so? deactivate B. else. Hello, Assume following sequence diagram: A->B: Hi. Both loops and conditionals use interaction frames, which are ways of marking off a piece of a sequence diagram. The following sequence diagram example represents McDonald's ordering system: A UML Sequence Diagram showing student login sequence diagram. deactivate B. end.