#Sequence diagram if without else how to
#Sequence diagram if without else code

You can define parameters and a return value. The frame is drawn to cover the lifelines involved in the Reference refers to an interaction defined on another diagram. Negative the fragment shows an invalid interaction. Loop the fragment may execute multiple times, and the guard indicates the basis of iteration ( Figure 4.4).Ĭritical region the fragment can have only one thread executing it at once. Parallel each fragment is run in parallel. Equivalent to an alt with only one trace ( Figure 4.4). Optional the fragment executes only if the supplied condition is true. Common Operators for Interaction FramesĪlternative multiple fragments only the one whose condition is true will execute ( Figure 4.4). These notations have been dropped from sequence diagrams in UML 2, they are still legal on communication diagrams. Guards are a conditional expression placed in square brackets and indicate that the message is sent only if the guard is true.

$sequence diagram if without else$

You can add some text in square brackets to indicate the basis of the iteration. An iteration marker is a * added to the message name. Figure 4.5 shows some of these unofficial tweaks.įigure 4.5. As a result, you may see diagrams prepared before UML 2 and that use a different approach Īlso, some people don’t like the frames and prefer some of the older conventions. Only the fragment whose guard is true will execute. For conditional logic, you can use an alt operator and put a condition on each fragment. (Table 4.1 lists common operators for interaction frames.) To show a loop, you use the loop operand with a single fragment and put the basis of the iteration in the guard. Each frame hasĪn operator and each fragment may have a guard. In general, frames consist of some region of a sequence diagram that is divided into one or more fragments. Figure 4.4 shows a simple algorithm based on the following pseudocode:

Both loops and conditionals use interaction frames, which are ways of marking off a piece of a sequence diagram. Treat sequence diagrams as a visualization of how objects interact rather than

#Sequence diagram if without else code

If you want to show control structures like this, you are better off with anĪctivity diagram or indeed with code itself. This isn’t what sequence diagrams are good at.

#Sequence diagram if without else how to

UML Distilled: A Brief Guide to the Standard Object Modeling Language, 3rd EditionĪ common issue with sequence diagrams is how to show looping and conditional behavior. Place the condition for exiting the loop at the bottom left corner in square brackets. When that object's lifeline ends, you can place an X at the end of its lifeline to denote a destruction occurrence.Ī repetition or loop within a sequence diagram is depicted as a rectangle. Objects can be terminated early using an arrow labeled '>' that points to an X. Lifelines are vertical dashed lines that indicate the object's presence over time. Asynchronous messages are sent from an object that will not wait for a response from the receiver before continuing its tasks.

Use half-arrowed lines to represent asynchronous messages. Messages are arrows that represent communication between objects. When an object is busy executing a process or waiting for a reply message, use a thin gray rectangle placed vertically on its lifeline. Use the UML object symbol to illustrate class roles, but don't list object attributes.Īctivation boxes represent the time an object needs to complete a task. Search through SmartDraw's knowledge base, view frequently asked questions, or contact our support team.Ĭlass roles describe the way an object will behave in context. Read articles about best practices, find tips on collaborating, learn to give better presentations and more. The SmartDraw API allows you to skip the drawing process and generate diagrams from data automatically.Īdd data to shapes, import data, export manifests, and create data rules to change dashboards that update.Ĭheck out useful features that will make your life easier. Learn how to generate visuals like org charts and class diagrams from data.īrowse built-in data visualizers and see how you can build your own custom visualization. Learn how to combine free-form brainstorming with diagram blueprints all while collaborating with your team. Learn about all the types of diagrams you can create with SmartDraw. Get inspired by browsing examples and templates available in SmartDraw. Familiarize yourself with the UI, choosing templates, managing documents, and more. Learn how to make any type of visual with SmartDraw.