Interaction Diagrams Components
◆ Describe how groups of objects collaborate in some behavior ◆ Object
• often used to show how use cases or parts of use cases behave • shown as a box at the top of a vertical dashed line anOrderEntry
• Two kinds of interaction diagrams are Window
◆ lifeline
» sequence diagrams
• represents time flow
» collaboration diagrams
◆ We will focus on sequence diagrams Object
lifeline
Components Components
anOrderLine aStockItem
◆ Messages ◆ Two kinds of control information anOrder anOrderLine aStockItem
• communcation between objects • message conditions
» message sent only if condition is
◆ Special message types true
check() Self-delegation * Prepare() Condition
• self-delegation
• iteration marker check()
• return » message sent to multiple receiver
[Check = “true”]
objects remove()
needsToReorder() Iteration
Normal
message
Return
Example Sequence Diagram Tips on Sequence Diagrams
anOrderEntry anOrder anOrderLine aStockItem
Window ◆ Show conditional behavior on separate diagrams
Prepare() ◆ Use to show the behavior of several objects within a use case
* Prepare() • use a state diagram when you want to focus on one object across many use
Object check() Condition cases
Message [Check = “true”]
remove()
Iteration
needsToReorder()
Self-Delegation
[needsToReorder = “true]
new
Return
aReorderItem
Creation
[Check = “true”]
new
aDeliveryItem
1
State Diagrams Components
◆ Describe ◆ States
• the possible states a single object can get in to • represented as a rounded box
• how object changes state in response to events » name
» activities - process performed by object, long-running, interruptible
◆ form1 : do / activityName
◆ form2 : eventName / activityName
• initial state is special, represented as a filled circle
initial state
state
Checking
activity
Do / check item
Components Example State Diagram for Order Object
◆ Transitions
• allowable state change / get first item
[Not all items checked]
• represented as an arrow from one state to another / get next item [all items checked &&
Checking all items available] Dispatching
» form : Event [Guard] / Action
• events can be thought of as signals Do/ initiate
Do / check item delivery
• a guard is boolean condition Item Received
[all items available]
• actions are short-duration, interruptible processes carried out during transitions [all items checked && Cancelled
some items not in stock]
Cancelled
/ get first item
[Not all items checked] Item Received
/ get next item [some items not in stock]
Checking
Waiting
transition
Do / check item
Cancelled Delivered
Cancelled Cancelled
Self-transition
Using Superstates Concurrent State Diagrams
/ get first item
[Not all items checked] Active ◆ Payment authorization done concurrently
/ get next item [all items checked &&
Checking all items available] Dispatching
Do/ initiate [payment not OK]
Do / check item Authorizing
delivery
do / check
Item Received
[all items checked && payment
some items not in stock] [all items available]
[payment OK]
Item Received
[some items not in stock]
Rejected
Waiting Authorized
Cancelled
Cancelled Delivered Delivered
2
Concurrent State Diagram Tips on State Diagrams
◆ Describe behavior of one object, not many objects
• for many objects use interaction diagrams
Waiting Cancelled
◆ Don’t try to draw them for every object
Cancelled
Checking Dispatching
Delivered
Authorizing Authorized
Rejected
[payment not OK]
Activity Diagram Components
◆ Show the flow of a process from activity to activity ◆ Activities
• task that needs to be done
Receive
Order
Components Components
◆ Control flow ◆ Parallelism and synchronization
Receive
• Sequencing Supply • allows parallel threads to be created or destroyed
» temporal ordering of tasks • stops progress until all threads reach synchronization point
» can be guarded
• Decision Choose
» if-then-else construct Outstanding Receive
Order Items Order
» (not shown here)
• Multiple triggers * for each chosen order item
» indeterminate looping construct
Assign Goods
to Order Authorize Check Line
Payment Items
Dispatch
Order
3
Example Activity Diagram Tips on Using Activity Diagrams
Receive ◆ Good for exploring parallel process flows
Order Receive
Supply • analyzing a use case
* for each line item • understanding workflow across multiple use cases
on order • understanding multi-threaded applications
Authorize Check Line
Payment Item
Choose
Outstanding
◆ Poor at showing connections between objects and actions
[failed] Order Items • trying to understand how objects collaborate
[in stock]
• understanding object lifecycle behavior
Assign to
* for each chosen order item
[succeeded] Order
Cancel Assign Goods
Order
to Order
[need to reorder]
Reorder
Item
[all outstanding
order items filled]
[stock assigned to all line
items and payment authorized] Add Remainder
to Stock
Dispatch
Order
