Chapter 7b OOSAD: Activity Diagrams

*Activity*

A behavior that an object carries out while in a particular state.

*Merge*

A circular symbol where different paths converge.

*Branch*

A diamond symbol containing a condition whose results provide transitions to different paths of activities.

*Swimlanes*

Columns representing different organizational units of the system.

Use activity diagrams sparingly—𝑨𝒔𝒌 𝒕𝒉𝒆 𝒇𝒐𝒍𝒍𝒐𝒘𝒊𝒏𝒈 𝒒𝒖𝒆𝒔𝒕𝒊𝒐𝒏:

Does it add value or is it redundant?

*Activity Diagram*

Shows the conditional logic for the sequence of system activities needed to accomplish a business process.

*Fork*

The beginning of parallel activities.

*Join*

The end of parallel activities.

An activity diagram can show 𝒑𝒂𝒓𝒂𝒍𝒍𝒆𝒍 𝒂𝒄𝒕𝒊𝒗𝒊𝒕𝒊𝒆𝒔, where parallel activities begin with

a 𝒇𝒐𝒓𝒌.

An activity diagram is a flexible tool that can be used in a variety of situations. It can be used at

a 𝒉𝒊𝒈𝒉 𝒍𝒆𝒗𝒆𝒍 as well as at a 𝒍𝒐𝒘 level of 𝒂𝒃𝒔𝒕𝒓𝒂𝒄𝒕𝒊𝒐𝒏.

What connects the circle with the first activity?

an 𝒂𝒓𝒓𝒐𝒘.

The 𝒆𝒏𝒅 of the process is also indicated with a filled in circle, but it is also

surrounded by another 𝒂𝒏𝒐𝒕𝒉𝒆𝒓 𝒄𝒊𝒓𝒄𝒍𝒆.

Model {𝔀𝓱𝓪𝓽} 2 steps in a 𝒄𝒐𝒎𝒑𝒖𝒕𝒂𝒕𝒊𝒐𝒏 𝒑𝒓𝒐𝒄𝒆𝒔𝒔.

the 𝒔𝒆𝒒𝒖𝒆𝒏𝒕𝒊𝒂𝒍 and 𝒄𝒐𝒏𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒔𝒕𝒆𝒑𝒔.

An activity diagram should only be used when it

𝒂𝒅𝒅𝒔 𝒗𝒂𝒍𝒖𝒆 to the project.

The symbol that illustrates a choice that must be made is a {𝔀𝓱𝓪𝓽}, and it is called

𝒅𝒊𝒂𝒎𝒐𝒏𝒅; a 𝒃𝒓𝒂𝒏𝒄𝒉.

The 𝒊𝒏𝒕𝒆𝒓𝒑𝒓𝒆𝒕𝒂𝒕𝒊𝒐𝒏 of the term activity depends on the perspective from which one is

𝒅𝒓𝒂𝒘𝒊𝒏𝒈 the diagram.

Help in identifying

𝒆𝒙𝒕𝒆𝒏𝒔𝒊𝒐𝒏𝒔 in a use case.

The 𝒃𝒆𝒈𝒊𝒏𝒏𝒊𝒏𝒈 of the process is indicated with a

𝒇𝒊𝒍𝒍𝒆𝒅 𝒊𝒏 𝒄𝒊𝒓𝒄𝒍𝒆.

Depict the

𝒇𝒍𝒐𝒘 𝒐𝒇 𝒄𝒐𝒏𝒕𝒓𝒐𝒍 from activity to activity.

Activity diagrams can be used to show the {𝔀𝓱𝓪𝓽} of a use case.

𝒍𝒐𝒈𝒊𝒄

Each 𝒂𝒄𝒕𝒊𝒗𝒊𝒕𝒚 is represented with a

𝒓𝒐𝒖𝒏𝒅𝒆𝒅 𝒓𝒆𝒄𝒕𝒂𝒏𝒈𝒍𝒆 with the action performed by that activity 𝒘𝒓𝒊𝒕𝒕𝒆𝒏 𝒊𝒏𝒔𝒊𝒅𝒆.

Help in use case analysis to understand

𝒘𝒉𝒂𝒕 𝒂𝒄𝒕𝒊𝒐𝒏𝒔 need to take place.

Model

𝒘𝒐𝒓𝒌 𝒇𝒍𝒐𝒘 and 𝒃𝒖𝒔𝒊𝒏𝒆𝒔𝒔 𝒑𝒓𝒐𝒄𝒆𝒔𝒔𝒆𝒔.