Moving from “lots of Requirements” to “organized Product Design” Product Design ? User/Market/Business “Requirements” May be in various forms May also be in various forms --- But can we organize this a bit better --- ?

One Way to “Transform” - Functionalities - Data - Non-Functionality (constraints) - U. I. - System Interfaces - Business/Workflow - Input-process-output (Activity Diagram, DataFlowDiagram & ERD & Use Case) - Add functionalities/interfaces (e.g. security check; portability) - Shorten functional algorithm (e.g. performance) -Screen Looks; Dialogue sequence - Database/File Design - Pass Control and Data exchange One form of Requirements “transformed” form of Requirements

Where Do We Go with This? - Input-process-output (Activity Diagram, DataFlowDiagram & ERD & Use Case) - Add functionalities/interfaces (e.g. security check; portability) - Shorten functional algorithm (e.g. performance) -Screen Looks; Dialogue sequence - Database/File Design - Pass Control and Data exchange ? M-V-C screens process DB Layered U. I. PROCPROC proc DB How Do We “Decompose” & “Compose”......

Top-Down / Hierarchical “Structural Breakdown” inputs outputs inputs outputs

Assembling Parts/ OO Approach Class AClass B Class C Class D

Let’s Look to Your Assignment for Clue “Model the Software to Describe Solar System” Almost 90% (past classes) of the students provided: –Picture(s) of the solar system –A description of what this picture represents and how a user may interact with it to get more details: A picture of the more “detail” of a specific planet Any further interaction to get additional features –Modify the picture size of the planet –Rotate the planet –Get detail information about the planet Another word --- many of you described how “users” would a) evoke the solar system software and how “users” may b) interact with it Some used Activity Diagram to depict user “interactions” with the “Solar System” “pictures” and “sub-pictures” the functionalities of the Solar System

A “Transitional Technique” for Requirements or Product Design Specification - - > Use Case Modeling Requirements Document (pages of English Statements and Diagrams) Analyze & Organize the “function/features” Use Case (a) Diagram Use Case (b) Description

Scenario & Use Case in Use Case Modeling Many of the “function and features” in the Requirements Document or Product Design may be viewed as “scenarios”: –Scenario: describes an set of interactions between a “particular” individual and the system. (e.g. Joe moves the cursor to the start button and presses it; then the system displays the overall solar system panel within in.1 seconds ) –A Use Case generalizes the scenarios: describes the interactions (in general form) between an “actor” (abstract individual or another system or environment) and the system (e.g. A user presses the start button and the solar system software displays the overall solar system panel within.1 second ) Note: Many use “scenario’ and “use-case” interchangeably

(activity diagram) for Use Case Development Process Study/rewrite scenarios Analyze the scenarios & pick the “actors” Use Case Diagram & Descriptions Initial Req. Document Use Case Development Initial Req. Document: Docs Use Case Diagram & Description : Docs Rewrite the scenarios Into Use Cases Associate Actors to the Use Cases “Abstract” the Use Cases And Draw Use Case Diagram

Use Case Diagram The diagram is made of the following: –Use cases (“functionality/feature” provided by the system) ---- in “bubble” diagram forms. –Actors (an external entity which interact with the use cases) ---- in a “stick figure” diagram forms –Association (relates the actors to the use case) ---- using lines –A frame (distinguishes the “system” and the external actors) ---- using a boundary line

UML: Use Case Diagram to represent Use Cases (this is a “static” model) High Level Steps (not necessarily always in sequence): 1.Analyze the scenarios 2.Decide on and create the system boundary 3.Identify the actor(s) 4.Convert the scenarios into abstract use cases 5.Describe the threads of activities that are necessary to support the actors’ needs; these threads of activities “expands” into more detailed use-case descriptions rotate picture users Solar System Display Individual item details > Extension pts : planets, sun Display Static Solar System In reality, we iterate over these steps! system admin & support System startup/ shutdown

Reviewing the Use Case Diagram Use Case Diagram should be “reviewed” for: –All major functionalities and features to be provided by the product is included (completeness) Check against the requirements list for completeness in coverage –Make sure that there is no duplication nor inconsistency within and among the use cases. –Make sure that all actors (completeness) are included.

UML: Use Case Descriptions (this provides a bit more “dynamic” model) A Use Case Description is a specification of the interaction between the actor(s) and the use case in system(product): 1.Specifies the actions by the actor 2.Specifies the system responses to the actions There is no one standard notation for Use Case Descriptions –You can include any of the “forms” or pictures –but preferred one is “text”

A Sample Use Case Description Template 1.Use Case Name or/number: (for identification purpose) 2.Actors: agents participating in the use case 3.Stakeholders & needs: identify those who have the needs for this use case (e.g. sources of this requirements) 4.Pre-Conditions: conditions that must be true prior to the activity or operation 5.Post-Conditions: conditions that must be true when the operation or activity completes 6.Trigger: an event that causes the use case to begin 7.Basic Flow: A description of the flow of interaction between the actor(s) and the product use case 8.Extensions : description of alternative flow of interaction from the normal flow, such as an error processing flow. Meat Of Descrip. Note: We may include diagrams (such as the activity diagram or the pictorial representation of the UI screens) in the Use Case Description. See example –page 170 of your text