20101007 how smart use cases drive web development

1. Sander Hoogendoorn Principal Technology Officer Capgemini HOW SMART USE CASES DRIVE WEB DEVELOPMENT

2. 2HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Capgemini Principal technology officer Global agile thought leader Chief architect Accelerated Delivery Platform (ADP) Other Author books and +200 articles in international magazines Appreciated speaker at +80 international conferences Microsoft Partner Advisory Council .NET Capping IT Off Blog Columns in Software Release Magazine, SDN Magazine Editorial boards Software Release Magazine, TiTM Advisory board @Portunity Web www.sanderhoogendoorn.com www.smartusecase.com Twitter / LinkedIn : aahoogendoorn SANDER HOOGENDOORN

3. 3HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved AGENDA Comparing requirements techniques Modeling smart use cases Smart use case driven software architecture Introducing the task pattern Generating code from smart use cases Unit testing smart use cases

5. User stories, huge cases and smart use cases REQUIREMENT TECHNIQUES COMPARED

9. 9HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved DIFFERENT LEVELS OF USE CASES Cloud level Kite level Sea level Fish level Clam level High summary Summary User goal Sub-function Too low Products Selling products Search book Insert orderline Sell book

11. 11HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Traditional use cases Smart use cases Format Textual Visual Granularity Different Unified Estimate Hard Easy Unit of work Lousy Good Reuse Incidental Normal Traceability Possible Normal Testability Poor Good Traditional use cases Only user goal level use cases Use cases ‘as they are intended’ A single use case describes a single elementary business process Differ in granularity too much Law of Large Numbers does not apply Smart use cases User goal and sub function level use cases Good unit of work and estimation A single elementary business process is modeled in a single use case diagram A single user goal level use case + auxiliary use cases at sub-function level Very similar granularity DIFFERENT LEVELS OF USE CASES

13. A YAGNI approach to requirements SMART USE CASES

14. 14HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved In traditional software development Analysis and design is done upfront Development only starts after all design is complete and perfect Consequences No room for new or changing insights Possibly unnecessary work Therefore Eliminate waste Maximize the amount of work not done Postpone work until you really need it Benefits No unnecessary analysis and design work Allows for new and changing insights No handover, immediate feedback YAGNI. YOU AIN’T GONNA NEED IT

15. 15HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved AGILE REQUIREMENTS - APPROACH D E F Smart Use Cases A Project Scope D Use Cases A B C Hierarchical Processes B D D Hierarchical Processes Chronological Processes Cloud Level Kite Level Sea Level Fish Level C

18. 18HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Guidelines Identify re-use Model one form per use case Model one use case per web part Isolate unknown or complex functionality Model complex calculations Identify reports and analysis Isolate interaction with others Model services in service orientation Avoid low level interaction (database, technical services) IDENTIFYING SUB-FUNCTION LEVEL USE CASES

22. Stereotypes SMART USE CASES

23. 23HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Stereotypes in UML Marking model items gives explicit meaning to the model Predefined stereotypes Custom definable stereotypes Smart use case stereotypes Standardize analysis and design “This is a master-detail on product and order” “This service on customer is an aggregate” “We need a file import for handling the XMI” Facilitate easy estimation Commoditize realization of smart use case Facilitate easier (and automated) testing SMART USE CASE STEREOTYPES

25. An overview SMART USE CASE DRIVEN ARCHITECTURE

26. 26HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Database consumer Domain oriented Data provided by database(s) But often database independent Service consumer Domain oriented Data provided by service or middleware But protocol independent (SOAP or REST?) Service provider Service oriented Data provided by contacts But domain oriented using data contracts USING REFERENCE ARCHITECTURES

27. 27HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Presentation Process Domain Data / Services Outside world Pages UserControls Panels Use cases Workflow Domain objects / Entities Factories / Repositories Enums / Value objects / Smart references [Mapping] Table Gateways Queries [Mapping] Database

28. 28HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Exact SAP BizTalk Java Presentation Process Domain Data / Services Outside world Pages UserControls Panels Use cases Workflow Domain objects / Entities Factories / Repositories Enums / Value objects / Smart references [Mapping] Service gateways Service locators [Mapping] Services / ESB

29. 29HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Presentation Process Domain Data / Services Outside world Service contracts Operation contracts Data contracts Use cases Services Domain objects / Entities Factories / Repositories Enums / Value objects / Smart references [Mapping] Table Gateways / Service Gateways Queries / Service Locators [Mapping] Database Services / ESB Exact SAP BizTalk Java

30. 30HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved ARCHITECTURE IN CODE Web Pages, controls Process Use cases / Tasks / Flow Domain Factories / Repositories Domain Objects / Business rules Enums / Value Objects / References Search Objects Data / Services Gateways Mappings / Describers Database

32. Introducing the Task Pattern SMART USE CASE DRIVEN ARCHITECTURE

34. 34HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Smart use cases Act as primary unit of work Model process and work flow Make traceable in code Interact with presentation and domain layers Create layer supertype (task) Create classes for individual smart use cases Why? Create traceability Facilitate reuse Implement model view controller Facilitate easier functional testing Cheapen application maintenance SMART USE CASES IN CODE

36. 36HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Command pattern – Definition Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations Task pattern – Definition Encapsulate a smart use case as an object, thereby letting you parameterize it from different requests. In practice Implement smart use cases independently Define a navigation mechanism Use smart use cases independently Allows for reuse of your smart use cases! Useful when Always ☺ Create a task manager! TASK PATTERN

48. Task management with the Manager-Provider Pattern SMART USE CASE DRIVEN ARCHITECTURE

49. 49HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Definition Create a simple static facade (manager) for a (set of) interfaced implementations (providers) In practice Manager holds one or a collection of providers Provider implement a particular interface Manager has methods to call methods from interface At run-time, using dependency injection, actual providers are injected MANAGER-PROVIDER PATTERN

56. 56HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Useful when Generic services need to be called, which may have different implementations Manager prevents having to loop through each of a list of providers Flexibility to add or remove providers without changing application code Providers differ e.g. in development code, test code or deployed code Use for Task Management View Management Binding and Persisting Resource Management State Management Logging Datasource interaction Testing! MANAGER-PROVIDER PATTERN

58. An introduction to pragmatic model driven development GENERATING CODE FROM SMART USE CASES

59. 59HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Forms Use cases Domain objects Data / Service classes Databases Software Architecture Tobago MDA Test scenario’s Frameworks Specifications Existing Applications Business models Domain Model Smart use cases User interface specification 1. Map your business processes to smart use cases 1. Map your business processes to smart use cases 2. Set up your domain model 2. Set up your domain model 3. Establish your software architecture(s) 3. Establish your software architecture(s) 4. Generate your code using a text template engine 4. Generate your code using a text template engine 5. Finalize your application 5. Finalize your application

60. 60HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Characteristics Load UML model (expressed in XMI) Load templates (from flat files) Combine elements from UML model with templates to generate deliverables Templates Templates contains code that runs in template engine Templates might use a folder model Generation process Ability to generate all or individual UML model elements Which UML model elements are supported? Generated deliverables can be code but also any other document type MODEL DRIVEN DEVELOPMENT – TEMPLATE ENGINES

61. 61HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved MODEL DRIVEN DEVELOPMENT - TEMPLATE ENGINES Template engine knows (part of) the UML meta model Template engine knows (part of) the UML meta model Properties can be used in templates Properties can be used in templates

64. A quick example GENERATING CODE

65. 65HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved A SIMPLE SMART USE CASE MODEL uc Manage Customer Site Administrator (from Actors) «master detail» Manage Customer «search» Select Customer «define» Define Contact «extend» «include»

66. 66HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved A SIMPLE DOMAIN MODEL class Budapest.Business «business class» Customer + Name: string + Address: string + Postcode: Postcode + City: string + Country: SmartRef + Website: Url [0..1] «business class» Contact + Name: string + Email: Email [0..1] + Phone: PhoneNumber [0..1] + Department: Departments «enumeration» Departments Sales Purchasing Helpdesk Management *

71. Unit testing at the right level UNIT TESTING SMART USE CASES

73. 73HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved UNIT TESTING SMART USE CASES Unit test what? Methods from the task pattern Methods that are called from presentation Methods that collaborate with other use cases Methods that interact with domain How? Create unit test for each smart use case Run methods from smart use case Validate outcome (using asserts) Why? Great code coverage Regressions testing on smart use cases Code generation makes light work

75. 75HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved UNIT TESTING SMART USE CASES Test methods that interact with domain Set up (in)valid domain object Run method from use case Validate outcome

76. Introducing a light weight smart use case unit testing framework UNIT TESTING SMART USE CASES

77. 77HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Test environment Create test manager (using manager-provider) Mock actual use case environment Log events from environment to test manager Asserts by querying test manager Task management (Possibly) avoid other task getting started View management Don’t request actual web pages or forms Method calls from web pages are tested Domain Handle actual validation, saves, removes Make sure business rules validate Validation Validate, but handle by logging A LIGHTWEIGHT SMART USE CASE UNIT TESTING FRAMEWORK

82. 82HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved TEST MANAGER – RUNNING TESTS Test methods that interact with domain Set up (in)valid domain object Run method from use case Validate outcome

83. TAKEAWAYS

84. 84HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Smart use cases Solid unit of work in agile projects Easy estimation Identifying functional re-use early in projects Guarantee front-to-back traceability Great unit for (automated) testing Apply stereotypes for even more standardization Use a REAL modeling tool Software architecture Provide separate smart use cases layer Handles process, interaction and work flow Controller ++ TAKEAWAYS

85. 85HOW SMART USE CASES DRIVE WEB DEVELOPMENT ©2010 Capgemini. All Rights Reserved Coding Implement task pattern Implement task management Modeling provides for model driven development Testing Smart use cases allow for automated testing Great code coverage on all layers Mock actual task environment Run tests automated in nightly builds TAKEAWAYS

86. www.accelerateddeliveryplatform.com WWW.SMARTUSECASE.COM

87. sander.hoogendoorn@capgemini.com www.sanderhoogendoorn.com www.smartusecase.com @aahoogendoorn REFERENCES AND QUESTIONS