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L. 5 - 1 © A. H. Levis INCOSE LECTURE 5 OBJECT ORIENTATION FOR ARCHITECTING: A CANDIDATE PROCESS LEE W. WAGENHALS ALEXANDER H. LEVIS C4ISR ARCHITECTURES.

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Presentation on theme: "L. 5 - 1 © A. H. Levis INCOSE LECTURE 5 OBJECT ORIENTATION FOR ARCHITECTING: A CANDIDATE PROCESS LEE W. WAGENHALS ALEXANDER H. LEVIS C4ISR ARCHITECTURES."— Presentation transcript:

1 L © A. H. Levis INCOSE LECTURE 5 OBJECT ORIENTATION FOR ARCHITECTING: A CANDIDATE PROCESS LEE W. WAGENHALS ALEXANDER H. LEVIS C4ISR ARCHITECTURES AND THEIR IMPLEMENTATION CHALLENGES

2 L © A. H. Levis INCOSE OUTLINE Introduction - Need for a process An OO Process Example Summary

3 L © A. H. Levis INCOSE CONCEPTUAL PROBLEMS We have seen that the structured analysis approach requires the functional architecture view composed of the activity model, the data model and the rule model plus a consistent physical architecture view. While object orientation offers an alternative to structured analysis, the Uniform Modeling Language does not offer a process for building complete architecture descriptions The goal of most OO texts is to develop software, not architectures Two new problems arise: –What is the set of UML diagrams that should be used to represent a complete architecture of an information system or C4ISR? –Can an Object Oriented process be developed and used to design an architecture? As with structured analysis, our requirement is that the combination of information contained in the set of views must be sufficient to yield the specified products and to construct an executable model of the architecture.

4 L © A. H. Levis INCOSE OBJECT ORIENTATION APPROACH: ANALYSIS PHASE Unless the Logical and Physical Architectures are restricted to very high level representations, the Operational Concept is needed to drive both representations and keep them compatible LOGICAL ARCHITECTURE VIEW OPERATIONAL CONCEPT PHYSICAL ARCHITECTURE VIEW MISSION USE CASE ANALYSIS ORGANIZATION MODEL

5 L © A. H. Levis INCOSE LOGICAL ARCHITECTURE VIEW LOGICAL ARCHITECTURE VIEW IS BEHAVIORAL DIAGRAMS including Rule Model CLASS DIAGRAM DICTIONARYDICTIONARY DATADATA

6 L © A. H. Levis INCOSE A DETAILED VIEW ORGANIZATION MODEL OPERATIONAL CONCEPT LOGICAL ARCHITECTURE VIEW PHYSICAL ARCHITECTURE VIEW EXECUTABLE MODEL MOPs, MOEs TECHNICAL ARCHITECTURE VIEW BEHAVIORAL DIAGRAMS (inc.Rule Model) CLASS DIAGRAM DATA DICT. MISSION EVALUATION PHASE

7 L © A. H. Levis INCOSE A REQUIREMENTS VIEW ORGANIZATION MODEL OPERATIONAL CONCEPT LOGICAL ARCHITECTURE VIEW PHYSICAL ARCHITECTURE VIEW EXECUTABLE MODEL MOPs, MOEs TECHNICAL ARCHITECTURE VIEW BEHAVIORAL DIAGRAMS (inc.Rule Model) CLASS DIAGRAM DATA DICT. MISSION EVALUATION PHASE

8 L © A. H. Levis INCOSE A FIVE STAGE PROCESS A five-stage process has been developed that uses the Unified Modeling Language and the associated diagrams to design the Operational and Systems Architecture views The architecture information contained in the diagrams is then mapped into the C4ISR products Not all C4ISR products are derivable from the OO architecture design (nor are they derivable from the structured analysis approach) A high level description of the process is shown on the next viewgraph

9 L © A. H. Levis INCOSE A FIVE STAGE PROCESS GATHER DOMAIN INFORMATION DEVELOP CLASS DIAGRAMS DEVELOP BEHAVIORAL DIAGRAMS & RULE MODEL DEPICT ORGANIZATIONAL STRUCTURE DESCRIBE PHYSICAL ARCHITECTURE DEVELOP DEPLOYMENT DIAGRAM DEVELOP COMPONENT DIAGRAMS SYNTHESIS EXECUTABLE MODEL STAGE 0 STAGE 1 STAGE 2 STAGE 3 STAGE 4 LOGICAL PHYSICAL MAINTAIN INTEGRATED DICTIONARY ALL 0 FORMULATE OPERATIONAL CONCEPT DEVELOP USE CASES AND THEIR DIAGRAMS ENSURE CONCORDANCE

10 L © A. H. Levis INCOSE A FIVE-STAGE PROCESS STAGE 0: Problem Definition and Collection of Domain Information STAGE 1:Operational Concept and Requirements; Use Cases and Diagrams STAGE 2:Class Diagrams, Behavioral Diagrams, Rule Model, Concordance STAGE 3: Physical Nodes and Links; Component Diagrams, allocation to Physical Nodes and Links (Deployment Diagram) STAGE 4:Synthesis (executable model) All STAGESMaintain Integrated Dictionary

11 L © A. H. Levis INCOSE STAGE 0 Define Problem and Identify Domain Gather Domain Information Describe Physical Architecture –Legacy systems and their characteristics –Planned systems –Future systems and alternatives Note: Legacy systems and their interfaces can be thought as physical design constraints on the architecture

12 L © A. H. Levis INCOSE IDEF0 MODEL OF PROCESS Purpose: to describe a process for developing an information system architecture using Object Orientation View Point: System Architect Design Information System Architecture A0 Domain Knowledge Object Orientation & UML Guidelines Information System Architecture

13 L © A. H. Levis INCOSE OVERALL PROCESS

14 L © A. H. Levis INCOSE STAGE 1 Once the basic information has been assembled in Stage 0, the process starts by defining the Operational Concept that implies or includes organizations and actions or tasks. This is expressed as the operational concept graphic with a textual description The operational concept is expanded by developing Use Cases. These describe scenarios between users and the system for which the architecture is being developed. A scenario is a sequence of interactions between a user and a system. There is no specified format. Textual descriptions listing interactions with actor or system (noun), the next activity (verb), and result (noun) are used. Other formats include a table listing, for each interaction, Actor, System, Pre-condition and Post-condition.

15 L © A. H. Levis INCOSE STAGE 1 ESTABLISH REQUIREMENTS Domain Knowledge Object Orientation/UML Guidelines Operational Concept and Use Cases Formulate Operational Concept A11 Develop Use Cases A13 Determine Organizational Features A12 Use Cases with Diagrams Operational Concept Organizations

16 L © A. H. Levis INCOSE STAGE 2 Once the required operation of the system has been defined, the logical architecture for carrying out the use cases is designed. The architect decides what activities and information flows will accomplish the operational concept as defined by each use case, allocates those activities to Classes, determines the attributes that each class needs to carry out its activities (operations), and develops the rules for each operation. Concordance is crucial throughout this process which is iterative rather than sequential

17 L © A. H. Levis INCOSE DEVELOP LOGICAL ARCHITECTURE UML Based Logical Architecture Domain Knowledge Object Orientation/UML Guidelines Operational Concept and Use Cases Develop Class Diagram A21 Develop Behavioral Diagrams A22 Develop Rule Model A23 Ensure Concor- dance A24 Object Class Collaborations, activities, and links Object Class Diagram Rule Model Behavioral Diagrams Corrections

18 L © A. H. Levis INCOSE STAGE 2 (continued) It is the architects choice as to which model to begin with –The architect may start with a candidate set of classes and then describe the behavior using the behavioral diagrams (activity diagram or sequence diagram) –Alternatively the architect can start with behavioral diagrams, e.g. activity diagram, to determine how the use case will be carried out. Once the activity diagram is created, the activities can be allocated to objects and the activity diagram enhanced with swim lanes to show the interaction between classes. –Regardless of the starting point, the architect will quickly be working with a set of diagrams all showing different aspects of how the architecture will carry out each use case.

19 L © A. H. Levis INCOSE CONCORDANCE As with structured analysis, maintaining concordance between the model views is crucial Each type of behavioral diagram reflects the design of the same architecture. Each highlights a different aspect of that behavior. Activity Diagrams reflect the processes used to carry out the use cases. They describe the sequencing of activities. Decomposition of activities is supported. The activities will be carried out by the operations of the classes. Thus it is recommended that the names of the activities and the operations be the same. Once activities have been allocated to classes, then the flow of information between them can be determined from the activity diagram and must match the association paths on the collaboration diagram and the flows on the sequence diagram.

20 L © A. H. Levis INCOSE CONCORDANCE Activity A1 Activity O2 Activity O3 Activity A4 Object 1 Object 2 Object 1 Object 2 Operation O3 Operation O2 Object 1 Object 2 opeationO2() operationO3() activityA4() 2.operationO3() 1.operationO2() 3. activityA4() Activity Diagram Collaboration Diagram Class 1 Class 2 Operation O3 Operation O2 Class 3 Class Diagram Sequence Diagram

21 L © A. H. Levis INCOSE CONCORDANCE The links on the collaboration diagram are labeled with the messages that carry the information between the two objects. –UML message format » predecessor guard-condition sequence expression return value:=message_name (argument list). » e.g., 1.1, [x

22 L © A. H. Levis INCOSE CONCORDANCE The Class diagram is a composite structure of the collaboration diagrams. –The associations on the Class diagram must represent one or more links on the set of collaboration diagrams. »If there is a link on a collaboration diagram and no corresponding association on the class diagram, an error exists. »If an association exists and there is no corresponding link on any collaboration diagram, an error may exist. –Not that the association names are chosen to enhance overall understanding and they do not have to be the same as the message label of the links.

23 L © A. H. Levis INCOSE STAGE 3 Physical Architecture Domain Knowledge Object Orientation/UML Guidelines Operational Concept and Use Cases UML Based Logical Architecture Develop Physical Architecture A31 Develop Component Diagrams A32 Develop Deployment Diagram A33 System Nodes and Links Components UML Based

24 L © A. H. Levis INCOSE STAGE 3 In completing the physical architectures, use the principles that applied to structured analysis –Define system nodes and links using the operational concept and organizational features as a guide Objects are grouped into components to create component diagrams Components are allocated to system nodes in the physical architecture –All logical associations must be instantiated with communications links

25 L © A. H. Levis INCOSE EXAMPLE A simple example of an Automatic Teller Machine can be used to illustrate the process The operational concept is that we will create an architecture for a system that uses ATMs to allow bank customers to withdraw cash from their bank accounts at any time. –Two options will be available: a Fast Cash option that provides a set amount of cash, and a regular withdrawal where the customer can specify the amount of cash to be withdrawn –Customers use an ATM card issued by the bank to initiate the process. They must use a PIN.

26 L © A. H. Levis INCOSE USE CASE EXAMPLE Use Case:Withdrawal Actors:Customer, Bank Type:Primary Description:A customer arrives at an ATM with ATM Card to withdraw cash. The customer inserts the card into the ATM. The ATM prompts the customer to enter PIN. The customer enters PIN and the system authorizes the withdrawal. The customer enters the amount to be withdrawn. The ATM dispenses the cash and provides a receipt. The ATM sends transaction records to the Bank to update the account balance. On completion, the customer leaves with the cash and receipt

27 L © A. H. Levis INCOSE ATM Withdrawal FastCash Withdrawal Use Case Diagram of ATM User SSN FirstName LastName Address InsertCard() TypePIN() CollectReceipt() CollectCard() Select() EnterAmount() CollectCash() Bank BankCode Name ValidateUser() AuthorizeTransaction() STAGE 1

28 Activity Diagram of Withdrawal Use Case NewState2 Insert Card Type PIN Request PIN Request Receive Validation Display Options Select Options Enter Amount Request Amount Compare Cash Limit Read PIN Validate User Request Authorization Receive Authorization Collect Cash Dispense Cash Print Receipt and Eject Card Authorize Transaction Collected Receipt and Card [ Transaction Authorized ][ Transaction NotAuthorized ] [ User Validated ] [ User NotValidated ] [ Amount < CashLimit ] [ Amount > CashLimit ]

29 Withdraw FastCashWithdraw Card Account ATM 1..* transfer information Session Bank 1..* 1 1 manage 1..* 1 1 maintain 1..* 1 1 validate Transaction 1..* authorize User (from Use Case View) 1..* 1 1 own 1..* 1 1 has 1..* use 1..* 1 1 participate 1..* perform INITIAL CLASS DIAGRAM OF ATM 1 1..*

30 ALLOCATE ACTIVITIES TO CLASSES USER BANK ATM SESSION TRANSACTION

31 Activity Diagram of Withdrawal Use Case with Swim Lanes Activities are allocated to Objects Activities become operations The connectors in the Activity Diagram correspond to Associations in Class Diagram and links in Collaboration and Sequence Diagrams Messages labels can be added

32 L © A. H. Levis INCOSE ADDING OPERATIONS AND ATTRIBUTES Operations derived from Activity Model Attributes defined as needed based on rule model Transaction TransactionID Date Time ManageLog() RequestAuthorization() ReceiveAuthorization() ApproveWithdraw() Withdrawal Amount CashLimit RequestAmount() CompareCashLimit() FastCashWithdrawal FastCastAmount

33 L © A. H. Levis INCOSE RULE MODEL Based on the Activity Diagram Developed in the same manner as for Structured Analysis –Use Structure English, Decision Tables and Trees Rules apply only to the lowest level of decomposition in the Activity Diagram Ensure each Clause of rule matches either: –Attribute of Object –Message sent to the object (calling the activity/operation) –Message or return from the objects activity/operation As with data modeling in structured analysis, domains must be defined for each attribute and message

34 Sequence Diagram of FastCash Withdraw Use Case

35 L © A. H. Levis INCOSE SEQUENCE DIAGRAM Shows the sequence for messages between objects for the use case Must match the Activity Diagram in structure Emphasis is on the messages rather than the activities Messages must match the conditions or actions of the rule model for each activity operation

36 Collaboration Diagram of Withdrawal Use Case Must match the Sequence Diagram (and the Activity Diagram) : User : ATM : Bank : Session : Withdraw 13: CompareCashLimit() 1: InsertCard() 3: TypePIN() 9: Select (Withdraw) 18: CollectCash() 20: Select (Quit) 2: RequestPIN() 8: DisplayOptions() 17: DispenseCash(Amount) 19: DisplayOptions() 21: EjectCard() 22: PrintReceipt() 4: ActivateSession(CardNumber, PIN) 7: ConfirmValidation() 10: Activate (Withdraw) 16: ApproveWithdraw(Amount) 5: RequestValidation(CardNumber, PIN) 6: ValidateUser(CardNumber) 11: RequestAmount() 12: EnterAmount() 14: RequestAuthorization(TransactionID,CardNumber,Amount) 15: AuthorizeTransaction(TransactionID)

37 Class Diagram of ATM Class Diagram is a composite overlay of the collaboration diagrams Withdraw FastCashWithdraw Card Account ATM 1..* Session 1..* 11 has Bank 1..* 1 1 manage 1..* 1 1 maintain 1..* 1 1 validate Transaction 1..* authorize User 1..* 1 1 own 1..* 1 1 has 1..* use 1..* perform activate *

38 1 1 validate Transaction TransactionID Date Time ManageLog() RequestAuthorization() ReceiveAuthorization() ApproveWithdraw() 1..* authorize User SSN FirstName LastName Address InsertCard() TypePIN() CollectReceipt() CollectCard() Select() EnterAmount() CollectCash() (from Use Case View) 1..* 1 1 own 1..* 1 1 has 1..* use 1..* 1 1 perform FULL CLASS DIAGRAM

39 L © A. H. Levis INCOSE STATE CHARTS State Charts (or State Transition Diagrams) should be created for each Object Class –Note that this is different from our approach with Structure Analysis where Dynamics Models are produced for the entire system Same rules apply and concordance must be maintained –States are consistent with other behavioral diagrams –Transitions are annotated with events (message arrivals), guard functions (from rule model) and actions (that can be operations and match rule model) –Path from initial state to final state must match the threads on the activity diagram and match the life-lines on the sequence diagram

40 STATE CHART FOR ATM OBJECT CLASS Waiting for Card Initial State Waiting for PIN Card Inserted / RequestPIN() Displaying Options Waiting for Authorization Dispensing Cash Printing Reciept and Returning Card User Collects Money / PrintReceipt(), EjectCard() Waiting for Validation PIN Entered / ActivateSession() User Select Transaction / Activate(Transaction) Validation Received[ User Validated ] / DisplayOptions() Validation Received[ User NotValidated ] / PrintReceipt(), EjectCard() Authorization Received[ Transaction Authorized ] / DispenseCash() Authorization Received [ Transaction NotAuthorized OR Amount > Limit ] User collects card and receipt

41 L © A. H. Levis INCOSE SUMMARY We have demonstrated a candidate process by which the Object-Oriented paradigm can be applied to the architecture specification problem –Understanding and maintaining Concordance and the Integrated Dictionary is absolutely necessary Tools: –Rational Rose supports the creation of UML diagrams, but it does not support concordance in the manner needed for architecture development –Ptechs Framework supports object orientation and the creation of the UML diagrams; current DOD funded effort for the automatic generation of the Colored Petri net based executable model in progress.


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