Object Oriented Analysis & Design & UML (Unified Modeling Language)1 Part VI: Design Continuous Activity Diagams State Diagrams

Object Oriented Analysis & Design & UML (Unified Modeling Language) 2 Content Activity Diagams State Diagrams

3 Activity Diagrams

Object Oriented Analysis & Design & UML (Unified Modeling Language) 4 Activity Modeling a specialized type of behavioral modeling concerned with modeling the activities and responsibilities of elements. a special form of state machine to model the computations and workflow Represents the state of execution not states of objects applied in conjunction with sequence and collaboration modeling

Object Oriented Analysis & Design & UML (Unified Modeling Language) 5 Activity Diagrams widely used in analysis to model a use case flow flow between the use cases with no use of classes, objects, etc. but also in design to model details of operation details of algorithm

Using Activity Diagrams activity diagram can be attached to any modeling element for the purpose of modeling the behavior of that element. Activity diagrams are typically attached to use cases classes interfaces components nodes collaborations operations and methods Object Oriented Analysis & Design & UML (Unified Modeling Language) 6

Object Oriented Analysis & Design & UML (Unified Modeling Language) 7 Action States Operation of Object Oriented systems a society of objects Elements communicate with one another each element has the responsibility of reacting to the communications it receives. An action state processing as an element fulfills a responsibility Example (the project management system states) Project Manager Enters Report Criteria Project Management System Generates Report Printer Prints Report

Object Oriented Analysis & Design & UML (Unified Modeling Language) 8 Types of action states Initial action state the first action state A final action state the last action state is shown using “a bull's eye” An activity diagram may have only one initial action state, but may have any number of final action states.

Object Oriented Analysis & Design & UML (Unified Modeling Language) 9 Flow Transitions shows how action states are ordered or sequenced. Whenever an action or subactivity state finishes its work, there is a transition out of the state into the next state types of flow transitions: control-flow object-flow transitions

Object Oriented Analysis & Design & UML (Unified Modeling Language) 10 Control-Flow Transitions indicates the order of action states Once a source action state completes its processing, a target action state starts its processing

Object Oriented Analysis & Design & UML (Unified Modeling Language) 11 Example Control Flow Transitions task of generating a report for the project management system order of action states: The Project Manager Enters Report Criteria The Project Management System Generates Report The Printer Prints Report

Object Oriented Analysis & Design & UML (Unified Modeling Language) 12 Control-flow transitions

Object Oriented Analysis & Design & UML (Unified Modeling Language) 13 Default transitions Control-flow transitions are also known as default transitions or automatic transitions, because they are unlabeled and are immediately triggered after the source action state completes processing.

Object Oriented Analysis & Design & UML (Unified Modeling Language) 14 Decisions A decision involves selecting one control-flow transition out of many control-flow transitions based upon a condition

Object Oriented Analysis & Design & UML (Unified Modeling Language) 15 Swimlanes a visual region in an activity diagram Represents use cases classes components organizational units in business modeling roles in workflow modeling indicates the element has responsibility for action states within the region

Object Oriented Analysis & Design & UML (Unified Modeling Language) 16 Object-Flow Transitions Indicates an action state input or output an object can modify object state An object-flow transition is shown as a dashed arrow between an action state and an object. Activities may input and output objects and can modify object state show this on an activity diagram as an object flow

Object Oriented Analysis & Design & UML (Unified Modeling Language) 17 Types of Object-Flow Transitions An action state uses an object as input: show with object-flow transition arrow Point from the object to the action state. An action state updates or produces an object: Show with the object-flow transition arrow Point from the action state to the object

Object Oriented Analysis & Design & UML (Unified Modeling Language) 18 Control-flow and object-flow transitions Without unnecessary control-flow transitions

Signals A signal is a way of representing a package of information that is communicated asynchronously between two objects. A signal event occurs when an object receives a signal When an event is received by an object it may trigger a state transition in it Object Oriented Analysis & Design & UML (Unified Modeling Language) 19

Sending & Receiving Signals the signal called Order is sent to the :MailOrderCompany external object we wait in the signal receipt for a signal called Goods delivered Object Oriented Analysis & Design & UML (Unified Modeling Language) 20

Signals are classifiers Modeled as stereotyped classes. The purpose of a signal is to provide asynchronous communication of information between objects and so, unlike ordinary classes, they only have attributes and the single implicit operation send(targetSet) allows them to be sent to a set of target objects. As this operation is implicit, it is never actually shown on signal diagrams it is just assumed that it is there for every signal. The signal attributes specify the information content of the signal Object Oriented Analysis & Design & UML (Unified Modeling Language) 21

Example: GUI events a generalization hierarchy of raw GUI events modeled as signals Object Oriented Analysis & Design & UML (Unified Modeling Language) 22

Object Oriented Analysis & Design & UML (Unified Modeling Language) 23 Concurrency selecting multiple transitions simultaneously

24 State Diagrams Object Oriented Analysis & Design & UML (Unified Modeling Language)

Object Oriented Analysis & Design & UML (Unified Modeling Language) 25 State Diagrams also known as statechart diagrams state machines (in UML 2.0) depict the lifecycle of elements that make up a system State modeling is a specialized type of behavioral modeling concerned with modeling the lifecycle of an element

Object Oriented Analysis & Design & UML (Unified Modeling Language) 26 States: Definition A state is a condition of being at a certain time. is drawn as a rounded rectangle with the name of the state in the center can be a passive quality, Example: light object=> On and Off. an active quality (object is doing something Example: Person => moving, sleeping, reading, … Example: coffeemaker => Brewing

Object Oriented Analysis & Design & UML (Unified Modeling Language) 27 Simple States indicates a condition or situation of an element. Example: the project management system Inactive is not available to its users, because it is not started or has been shut down Active started and available to its users Suspended has encountered some severe error, Possible reason: is running low on secondary storage requires user intervention

Object Oriented Analysis & Design & UML (Unified Modeling Language) 28 Initial and Final States Initial state the state of an element, when it is created. is shown with a small solid filled circle. A final state the state of an element when it is destroyed. is shown with a circle surrounding a small solid filled circle a bull's eye

Object Oriented Analysis & Design & UML (Unified Modeling Language) 29 Transitions A transition, shown with an arrow represents a change of states from a source state to a target state A transition description, written along the arrow, describes the circumstances causing the state change to occur.

Object Oriented Analysis & Design & UML (Unified Modeling Language) 30 Trigger A trigger is an event cause a transition. Example: User input processing systems a keystroke trigger may cause the system to change states from Gathering input to Processing input.

Object Oriented Analysis & Design & UML (Unified Modeling Language) 31 Transition Variations A trigger with no guard the transition is taken when the trigger occurs. This is useful for modeling a state change in response to an event. A trigger with a guard the transition is taken when the trigger occurs if the guard evaluates to true. Otherwise, the transition isn't taken. Combining a trigger and a guard is useful for modeling a transition is blocked depending on a condition. Neither a trigger nor a guard are specified, the transition is taken immediately after the source state's internal behavior

Object Oriented Analysis & Design & UML (Unified Modeling Language) 32 The life cycle of an object the life cycle of an AccountApplication object as it passes from pending to approved or rejected and then to finalizing

Object Oriented Analysis & Design & UML (Unified Modeling Language) 33 Example how to use State diagram modeling a troll in a FPS game FPS: first-person shooter the troll's behavior is determined by his state

Object Oriented Analysis & Design & UML (Unified Modeling Language) 34 Composite States A composite state is a state contains one or more state diagrams. Each diagram belongs to a region, regions are divided by a dotted line A state in a region is referred to as a substate of the composite state. Composite states work as follows: when the composite state becomes active, the initial pseudostate of each region becomes active, and the contained state diagrams begin executing. if a trigger on the composite state occurs The contained state diagrams are interrupted

Object Oriented Analysis & Design & UML (Unified Modeling Language) 35 Composite States Example Composite states contain one or more state diagrams; execute in parallel

Object Oriented Analysis & Design & UML (Unified Modeling Language) 36 Advanced Pseudostates A choice pseudostate used to emphasize a Boolean condition determines which transition is followed. has guards represented on outgoing transitions the transition depends on the guard.

Object Oriented Analysis & Design & UML (Unified Modeling Language) 37 Fork and join pseudostates show branching into concurrent states and then rejoining

Object Oriented Analysis & Design & UML (Unified Modeling Language) 38 Signals transition-oriented view: to draw attention to transitions and transition behavior using special icons for transitions.

Object Oriented Analysis & Design & UML (Unified Modeling Language)39 End of Chapter