adesso lectures Software Development in Practice

01.01.2019 Software Development in Practice 2 Who‘s Talking?  Tom Hombergs  Team Lead & Software Architect at adesso AG  Java Blogger at reflectoring.io  Editor at baeldung.com  Organizer of Java User Group Dortmund hombergs@adesso.de github.com/thombergs

01.01.2019 Software Development in Practice 3 What we‘re trying to avoid…

01.01.2019 4 Process Models

Waterfall 01.01.2019 Software Development in Practice 5 Requirements Analysis Design Development Test Operations

V-Model 01.01.2019 Software Development in Practice 6 Requirements Specification System Specification Module Specification Software Architecture Coding Unit Tests Integration Tests System Integration Acceptance Tests

Scrum 01.01.2019 Software Development in Practice 7

Best Practices – Process Model 01.01.2019 Software Development in Practice 8  Start small.  Adapt the process model to your Needs.  Get feedback early & regularly.

01.01.2019 9 Task Management

Use Cases 01.01.2019 Software Development in Practice 10 Compose Blog Post Publish Blog Post Update Blog Post Publish on Social Media Subscribe Author Reader

Work Breakdown Structure 01.01.2019 11 Software Development in Practice Blog Project Compose Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add Blog Entity to Database Publish Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add „Published“ Field to Blog Entity Update Blog Post Display WYSIWYG-Editor Save Updated Blog Post to Database Add „Updated“ Field to Blog Entity Social Media Integration Publish to Facebook Publish to Twitter Subscribe Send E-Mail on new Blog Post Send E-Mail on updated Blog Post

Slicing of Tasks 01.01.2019 12 Software Development in Practice Blog Project Compose Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add Blog Entity to Database Publish Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add „Published“ Field to Blog Entity Update Blog Post Display WYSIWYG-Editor Save Updated Blog Post to Database Add „Updated“ Field to Blog Entity Social Media Integration Publish to Facebook Publish to Twitter Subscribe Send E-Mail on new Blog Post Send E-Mail on updated Blog Post - The Wrong Way

Slicing of Tasks – The Right Way 01.01.2019 13 Software Development in Practice Blog Project Compose Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add Blog Entity to Database Publish Blog Post Display WYSIWYG-Editor Save Blog Post to Database Add „Published“ Field to Blog Entity Update Blog Post Display WYSIWYG-Editor Save Updated Blog Post to Database Add „Updated“ Field to Blog Entity Social Media Integration Publish to Facebook Publish to Twitter Subscribe Send E-Mail on new Blog Post Send E-Mail on updated Blog Post

Best Practices – Task Management 01.01.2019 Software Development in Practice 14  Use a tool!  Adapt the tool to fit your needs.  Break features into tasks at the latest possible moment.  Slice tasks vertically.

01.01.2019 Software Development in Practice 15 Github Demo – Task Management

01.01.2019 16 Version Control

Where to put Source Code? 01.01.2019 Software Development in Practice 17 Local Hard Drive Code Network Drive Code Local Hard Drive Code Local Hard Drive Code Editing Conflicts!

Version Control 01.01.2019 Software Development in Practice 18 Local Hard Drive Code Version Control System Code Local Hard Drive Code Local Hard Drive Code

Branching 01.01.2019 Software Development in Practice 19 First Commit Start of a feature branch. These changes must not go live in version 1.0! Version 1.0 goes live! Hotfix for a bad bug. The bug disrupted work in the feature branch, so it got merged. Version 2.0 with the new feature goes live Code Review before merging

Advanced Branching 01.01.2019 Software Development in Practice 20 http://nvie.com/posts/a-successful- git-branching-model/

Best Practices – Version Control 01.01.2019 Software Development in Practice 21  Use version control!  Provide meaningful commit messages.  Don‘t keep unnecessary code.

01.01.2019 Software Development in Practice 22 Github Demo – Version Control

01.01.2019 23 Documentation

Document Requirements 01.01.2019 Software Development in Practice 24  Document Goals  Document Use Cases  Document Requirements Requirements further specify Use Cases Use Cases contribute to a Goal Pohl und Rupp, Basiswissen Requirements Engineering, dpunkt Verlag, 2015

Document a Goal 01.01.2019 Software Development in Practice 25

Document a Use Case 01.01.2019 Software Development in Practice 26

Document a Single Requirement 01.01.2019 Software Development in Practice 27

Document Architecture – The arc42 Template 01.01.2019 Software Development in Practice 28 1. Introduction & Goals 2. Constraints 3. Context 4. Solution Strategy 5. Building Blocks View 6. Runtime View 7. Deployment View 8. Concepts / Patterns 9. Design Decisions 10.Quality Scenarios 11.Technical Risks 12.Glossary www.arc42.de

Document Architecture – The arc42 Template 01.01.2019 Software Development in Practice 29 1. Introduction & Goals 2. Constraints 3. Context 4. Solution Strategy 5. Building Blocks View 6. Runtime View 7. Deployment View 8. Concepts / Patterns 9. Design Decisions 10.Quality Scenarios 11.Technical Risks 12.Glossary www.arc42.de

Document Architecture – Context 01.01.2019 Software Development in Practice 30

Document Architecture – Building Blocks 01.01.2019 Software Development in Practice 31

Document Architecture – Example Patterns 01.01.2019 Software Development in Practice 32  Transactions  Logging  Exception-Handling  Unit-Testing  Integration-Testing  Security  Coding Conventions  Internationalization  Scalability  High Availability  Buildmanagement  Database Access  Migration  Session Handling  User Interface  … www.arc42.de

Best Practices – Documentation 01.01.2019 Software Development in Practice 33  Document as little as necessary.  Treat documentation as you would source code.  Use a markup language.

Best Practices – Documentation 01.01.2019 Software Development in Practice 34  Document specifically for each stakeholder group.  Update documentation when a task is done, not when the project is done.  Documentation is a team effort.

01.01.2019 Software Development in Practice 35 Github Demo - Documentation

01.01.2019 36

01.01.2019 37 Testing

01.01.2019 Software Development in Practice 38 Testing Pyramid Unit Tests Integration Tests End to End Tests Manual Tests

01.01.2019 Software Development in Practice 39 Test Coverage != Test Quality @Test public void testAbsoluteSum(){ Calculator calculator = new Calculator(); assertThat(calculator.abslouteSum(-1,2)).isEqualTo(3); } public class Calculator{ public int absoluteSum(int a, int b){ return (a < 0 ? -a : -a) + (b < 0 ? -b : b); } } 100% Line Coverage, 1 Bug missed

01.01.2019 Software Development in Practice 40 Test Coverage != Test Quality @Test public void testAbsoluteSum(){ Calculator calculator = new Calculator(); assertThat(calculator.absoluteSum(-1,2)).isEqualTo(3); assertThat(calculator.absoluteSum(1,2)).isEqualTo(3); assertThat(calculator.absoluteSum(-1,-2)).isEqualTo(3); } public class Calculator{ public int absoluteSum(int a, int b){ return (a < 0 ? -a : -a) + (b < 0 ? -b : b); } } 100% Line Coverage, bug is flushed out

Best Practices – Testing 01.01.2019 Software Development in Practice 41  Write unit tests!  Write tests when a task is done, not when the project is done.  Don‘t aim for meaningless test coverage percentage.  Review one another‘s Ccode.  Manually test one another‘s features.

01.01.2019 42

01.01.2019 43 Continuous Integration

01.01.2019 Software Development in Practice 44 Modular Software Development Blog Post Management Visitor Statistics Social Media Integration E-Mail Notification

01.01.2019 Erfolgsfaktoren in der Softwareentwicklung 45 CI Pipeline

Best Practices – Continuous Integration 01.01.2019 Software Development in Practice 46  Separate concerns in separate modules.  Automate your build process.  Run unit tests and integration tests in the build process.  Build regularly.

01.01.2019 Software Development in Practice 47 Github Demo – Continuous Integration