Sequence Diagrams

Synchronous Message

Sender waits until is has received a response message before continuing

Asynchronous Message

Sender continues without waiting for a response message

• msg(par1,par2)

Response Message

• msg(par1,par2)

May be omitted if content and location are obvious

• att=msg(par1,par2):val

Object Creation

Arrowhead points to the head of the lifeline of the object to be created

• Keyword new

Object Destruction

Object is deleted

• Large cross (×) at the end of the lifeline

Found message

Sender of a message is unknown or not relevant

Lost message

Receiver of a message is unknown or not relevant

Time-consuming message

Message with duration:

• Usually messages are assumed to be transmitted without any loss of time

• Express that time elapses between the sending and the receipt of a message

Coregion

To model concurrent events of a single lifeline

• Order of events can be whatever

• Area of the lifeline to be covered by the coregion is marked by square brackets rotated by 90 degrees

Bad Smells - Design quality flaws (bad smells)

• God Class

• Excessive Class Length

• Excessive Method Length

• Excessive Inheritance use

• Excessive Parameter List

• Duplicate Code

• Cyclomatic Complexity

• Too Many Methods

• Too Many Fields

Fragment

A rectangular region that encapsulates a portion of the interaction between objects

Lines →

Think of them as method calls
A —> B A calls a method in B