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.
