#Sequence diagram if else example visio how to#
#Sequence diagram if else example visio professional#

Note: Creating and editing UML diagrams on Visio for the web requires a Visio Plan 1 or Visio Plan 2 license, which is purchased separately from Microsoft 365. Resize a class, enumeration, or interface shape by clicking the shape header to select it and then moving the yellow control point (on the right edge of the shape) left or right to decrease or increase the width of the shape.Īdd parameter and stereotype fields to your class shapes by selecting the shape, right-clicking and choosing the corresponding option from the pop-up menu. Choose the desired relationship from the Set Connector Type menu. To change the relationship types, right-click the connector. You can also add a new member by right-clicking an existing member and choosing the option to insert a member.Ĭonnect two shapes with UML connectors to represent the relationships between the shapes. To add more members to the class, enumeration or interface shape, drag the member shape from the shape panel to the respective shape. To rename text labels, double-click the labels. Now, drag shapes you want to include in your diagram from the Shapes window to the page. This option makes connection points appear when you start connecting shapes. On the View tab, make sure the check box next to Connection Points is selected. If you still don’t see it, click the Expand the Shapes window button on the left. If you don’t see it, go to View > Task Panes and make sure that Shapes is selected. You should see the Shapes window next to the diagram. (A description of each one is shown on the right when you select it.) Then select either Metric Units or US Units. In the dialog box, select the blank template or one of the three starter diagrams. Or if you have a file open already, click File > New.

#Sequence diagram if else example visio professional#

(The Professional editions of Visio include support for the UML Class diagram and stencil, but the Standard editions don't.) But for 'simple' exception handling, I think a break is a better way to represent it, then alt.When you start a new class diagram, the UML Class stencil appears, along with shapes that conform to the UML 2.5 standard. ConclusionĪs always, the best method depends on the scenario. This is ofcourse a very simple example, and you can have a lot more interaction in the break interaction operator, like logging or transaction handling. I think it even makes things better, because you can see where a sequence stops when an exception occurs. What I like about this way of displaying exception handling is that it makes the diagram much less cluttered.

In this example the exception isn't caught until it enters the UI, in this case the ATM. Using a break interaction operator, it would look something like this: Let's take a look when the situation when something happens, what causes the ATM to decline de withdrawal. When the guard condition is true, the current interaction run is abandoned and the clause in the break interaction operand runs. The break interaction operator is similar to the break mechanism in other programming languages. This looks nice, for a small diagram, but once the diagram starts to grow and you get a lot of nested alt interaction operations, you might start to loose the overview. Using an alt interaction operator, it would look something like this: The else clause of the alternative combined fragment runs when no other option is selected.

If there is no guard, the operand always runs when it is selected. However, as for any operand, the selected operand in the alternative structure runs only if the guard condition tests true. Only one of the offered alternatives runs on any pass through the interaction. The server confirms the withdrawal is approved and, the service passes this on to the ATM's UI and the ATM dispenses the money.Īn alternative interaction operator represents the logic equivalent of an if-then-else statement. The customer enters the data, the ATM calls a service, which calls the bank's server. I'll describe both methods using a classical example: withdraw money from an ATM when the balance is too low. They both use interaction operators, alt and break.

#Sequence diagram if else example visio how to#

1Īfter searching for quite a while on how to model exception handling in a UML Sequence Diagram I found two ways to represent exception handling in a UML Sequence Diagram. There are several proposed notations for exception handling. Some clumsy approaches to model try-catch blocks are by utilizing combined fragments - alt (alternatives) and breaks, while adding stereotypes for reply messages representing thrown exceptions. UML provides neither notation to model exception handling in sequence diagrams nor any reasoning why it is absent.