Loops, Alts, and Refs

Loops

You know what loops are, right? For-loops, while-loops, etc. They are pretty simple in Interaction Sequence Diagrams. Just bind the messages that will be looped in a new frame, and remember to name the condition! While the condition is true, all the action within the loop frame will be repeated. Pretty simple, huh?

Alternatives

Now for your if-statements. In Interaction Sequence diagrams, they are alternatives. Similar to loops, you bind these messages in a new frame, with the title alt and the different conditions that will result in each path. A dashed line divides the different conditions.

References

The interaction sequence diagrams shown above are all fairly small and succinct. However, some diagrams might grow considerably large. In other cases, certain parts of your interactions might be derived from others. For this, we use References that reference other interaction sequence diagrams.

Fairly simply, you place a frame in the one diagram with the name of the referenced interaction.

Interaction 1 is referenced inside Interaction 2. Note the message and reply going to and from the referenced interaction (Interaction 2) matches up with the message and reply in referencing interaction (Interaction 1).