Part 2: Creating UML Diagrams

UML Diagrams Guide

Tutorials and examples

As we mentioned in the previous section, though there are 14 different types of UML diagrams, developers typically use just a few to cover most of their modeling needs. In this section, we’ll discuss how to create activity diagrams, class diagrams, sequence diagrams, and use case diagrams.

Templates and shapes for these and more UML diagram types are available in Cacoo.

Activity Diagram

Actions are tasks performed by a user, the system, or both in collaboration.

Connectors link the actions in sequence.

Nodes indicate the start or end of an activity. They can also indicate a fork or merge.

Activity Diagram

 

How to create an Activity Diagram in Cacoo:

  1. In the Cacoo editor, go to Templates and select the Activity Diagram template.
  2. Use round-edged rectangles to represent each action.
  3. Use lines to demonstrate the flow of actions from one to another.
  4. Use a circle to indicate the end of an activity.
  5. Optionally, arrange actions into swimlanes corresponding to different objects or business roles that perform the actions.
  6. Save your diagram.

Class Diagram

Classes represent data or object types. They are visualized using a rectangular shape with the class name as the top section.

Attributes are the named values that every instance of a type can have. They are listed under the class name.

Methods are the functions that instances of a type can perform. They are listed below attributes.

Class Diagram

How to create a Class Diagram in Cacoo:

  1. In the Cacoo editor, go to templates and select the Class Diagram template.
  2. Add all classes, attributes, and methods.
  3. Add new class shapes as necessary to fit your data.
  4. Use lines to draw any associations, inheritances, or dependencies between types. Your notation style will determine the styling of these lines.
  5. Save your diagram.

Sequence Diagram

Classes represent data or object types. They are visualized using a rectangular shape.

Lifelines are vertical lines that represent the sequence of events that occur to a participant as time progresses. This participant can be an instance of a class, component, or actor.

Messages are represented by lines between objects.

Sequence Diagram_1 Sequence Diagram_2

How to create a Sequence Diagram in Cacoo:

  1. In the Cacoo editor, go to Templates and select the Sequence Diagram template.
  2. Use rectangular boxes to indicate class instance names, class names, or objects.
  3. Use vertical lifelines to show sequences of messages in chronological order and horizontal elements to show object instances as messages are relayed.
  4. Draw lines to represent the sender and receiver of messages. Use solid arrowheads to symbolize synchronous messages, open arrowheads for asynchronous messages, and dashed lines for callback messages.
  5. Save your diagram.

Use Case Diagram

Actors represent users, organizations, or external systems that interact with your application or system. An actor is a kind of type.

Use Cases represent the actions performed by one or more actors in the pursuit of a particular goal. A use case is a kind of type.

Associations indicate where an actor takes part in a use case.

Use Case Diagram_1 Use Case Diagram_2

How to create a Use Case Diagram in Cacoo:

  1. In the Cacoo editor, go to Templates and select the Use Case Diagram template.
  2. Label your actors with stick figures (which can be found under Stencils > Software > UML) or other relevant illustrations.
  3. Use ovals to label your use cases.
  4. Use lines to model the relationships between actors and use cases.
  5. Save your diagram.

UML Templates and Shapes

While creating UML diagrams from scratch is easy with Cacoo, using templates can greatly speed up your diagramming process.

There are many different types of UML diagram templates to choose from in Cacoo. Simply open the editor, choose a template to get you started, and begin customizing it to your flow.

If you come up with a diagram you think you’ll want to replicate, save it as a new template or stencil. With custom templates and stencils, you can recreate your best work again and again.

Additional Cacoo Resources:

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