Module 16: Physical Design Rationalization

Objectives At the end of this module, you will be able to Understand project and organizational priorities for component packaging and distribution Transform objects into services-based components using the logical design Distribute and package components across the n tiers of the application Use strategy and prototypes to refine packaging and distribution

Lessons 1. Determining a Component Packaging and Distribution Strategy 2. Transforming Objects into Services-Based Components 3. Distributing Components Across Topologies 4. Refining Packaging and Distribution

Lesson 1: Determining a Component Packaging and Distribution Strategy Understanding project and organizational priorities for packaging and distribution

Determining Packaging and Distribution Consider packaging rationales Service category Scalability Performance Manageability Reuse Business context Granularity Align with programming model Example: Stateless and scalable Determine the design trade-offs that impact strategy based on rationales

Reuse and Component Granularity At what level do you get maximum reuse and granularity? Component Granularity Potential for Reuse High LargeSmall Low Within each development environment is an optimum component size that maximizes return on reuse

As a class: 15 minutes Activity Activity 11: Considering Design Factors and Trade-offs Use a hotel property management system as a basis What types of factors and trade-offs would you consider for a component packaging and distribution strategy?

Lesson 2: Transforming Objects into Services-Based Components Transforming objects into services-based components using the logical design

Defining Candidate Components Remember that the focus of rationalization is distributing services among components Use candidate components to provide a bridge between logical objects and service distribution Derive candidate components from the logical object model by iterating through the packaging rationales Make the first cut at components by using the category-of-service rationale

Business Services User Services Data Services User Component Business Component Data Component A B C D Preliminary Components Objects A BC D Moving from Logical to Physical Design

Lesson 3: Distributing Components Across Topologies Distributing and packaging components across the n tiers of the application

Defining a Preliminary Distribution Define components based on category of service and then align them with the proposed component topology Match services to logical tiers to create a distribution baseline Validate and use the other rationales in the packaging strategy to evolve the distribution of services

Distributing Candidate Components User and Business Services Data and Business Services Business Services Validatecustomer Customer Update customer Get customer Replicate customer Customer Archivecustomer Retrievecustomer Assignroom Invoice customer Findcustomer Displaycustomer Customer Preliminary Component Distribution

Lab Lab 7: Distributing Services to Create Candidate Components Use your services and objects from Labs 3 and 4 Refer to the Service Distribution Template Draft a model for distributing the preliminary components across the service tiers Show work on flip charts In small groups: 30 minutes

Lesson 4: Refining Packaging and Distribution Using strategy and prototypes to refine packaging and distribution

Validating Components Think of validation as a fundamental aspect of design, not as a distinct design step Use validation as the trigger for design iteration and evolution Validate against Packaging strategy Design goals Application requirements Logical design Enterprise architecture Prototype, prototype, prototype to evolve the deployment model Possibly update the enterprise architecture

Refining Component Packaging and Distribution Focus on services instead of components Use component/service interaction diagrams to document dependencies Distribute services across component topology as required by packaging rationales Group services into components based on physical location, packaging rationale, and technology constraints Use cohesion and coupling to measure the effectiveness of packaging Address both upward and downward scalability

Cohesion The relationship among different internal elements of a component Receive Payment Component

Coupling The relationship of a component to other components Enter Gift Shop Charges Component Receive Payment Component Check Out Guest Component

Packaging Goal High cohesion Provides a better definition of the components function and behavior Example: Organizing services by business function so that each component has only the services that pertain to its function Loose coupling Provides more flexibility and independence and leads to better defined and simpler interfaces Example: Organizing relationships among components by business function so that each component interfaces with the minimum number of other components for access to data

In small groups: 15 minutes Activity Activity 12: Repackaging and Redistributing Services Use the service distribution from Lab 7 as a basis What is your understanding of techniques for repackaging and redistributing components?

Deliverables of the Rationalization Baseline Task Determining a packaging and distribution strategy Transforming objects into services-based components Distributing components across topologies Using strategy and prototypes to refine packaging and distribution Deliverable Packaging and distribution strategy Services-based components Deployment model Future network topology Future data topology Future component topology Baselined deployment model Rationalization Baseline Rationalization

Summary What are the packaging rationales? What is the focus of physical design rationalization? What is the process for refining component packaging and distribution? What are cohesion and coupling? What are the packaging goals for cohesion and coupling? Summary