Select an interaction fragment with more than one condition defined. In this case you would preferably put two fragments, one with the correct operation guard and the second one with a condition that should cause a break. A Combined Fragment used in a UML Sequence diagrams as rendered using Sparx Systems. Whatever flow is after the combined fragment is executed normally anyway. There might be also a situation when none of the guards evaluate to true and no fragment is executed in such case. When an alt combined fragment is met its guard conditions are evaluated and only the eventual one fragment which guard evaluates to true is executed. If any additional actions should happen in case of a break, they should be put after the opt combined fragment. The opt fragment should have a guard that is opposite to the condition at which the flow should stop. Both loop and conditional use interaction frames, which are ways of marking off a piece of a sequence diagram. If you still prefer to model this in a sequence diagram, here’s the notation to use. You can put the part of the flow that is continued only if the break condition is not met inside the opt combined fragment. Treat sequence diagrams as a visualization of how objects interact rather than as a way of modeling control logic. The rest of a flow continues regardless of the condition. If more than one test section yields a true.
If one or more test sections yield a true value, one of the corresponding body sections will be executed. When the conditional node begins execution, the test sections of the clauses are executed.
When an opt combined fragment is met it executes only if a guard condition is true. A conditional node consists of one or more clauses, each consisting of a test section and a body section. The looping condition for that iteration is. In this case you would put the messages that shouldn't be executed in case of a break condition after the break combined fragment. The large rectangle that encloses the group of messages in the first sequence diagram defines an iteration. If the condition is not met, the combined fragment is omitted and the normal flow continues. Very simple, using Alt fragment Lets take an example of sequence diagram for an ATM machine.Let's say here you want IF card inserted is valid then prompt 'Enter Pin'. When a break combined fragment is met and its guard condition is true, only this fragment is still executed and then the execution of the interaction (flow) stops. and iteration with WHILE(c,A) and REPEAT(A,c), with condition c. However each of them provide you a valid possibility. Then the flow of control in sequence diagrams with branching is discussed. The first solution is the most convenient one - it exactly covers your case and you can also use the positive version of a break guard. The actual behaviour is hidden with interaction references (normalFlow for a flow that should normally be executed and breakFlow for any flow that should happen in case of a required break). Each of them I illustrate with a diagram showing how the respective combined fragment should be used. If guard condition size<0 becomes false loop terminates regardless of the. There are three options for this situation. UML Sequence Diagrams - graphical notation reference: Lifeline, Message.