## 20 24 September 15 - 20 ## +24 ## Dependency Injection in C++ A Practical Guide ## PETER MULDOON # Dependency Injection in C++: A Practical Guide Engineering CppCon 2024 September 18, 2024 Pete away and be able to use it ## Where will we be going? - Talk will be about inserting meaningful Dependency Injection in applications - Using various DI methods to achieve functionality swapping / instrumentation (or just giving up) • Talk is rooted in a real-world system not theory ## Basic Definitions ## Dependency Injection : 1. Decreases coupling between functionality blocks 2. Used to make a class/function

First Step Toward Standard C++ Dependency Management ## BILL HOFFMAN & BRET BROWN ## 20 23 October 01 - 06 ## Libraries: A First Step Toward Standard C++ Dependency Management October 3, 2023 Bloomberg Projects as portable as the code they contain! ✓ Projects should be “cattle,” not “pets”! ## Why dependency management? Consensus: Managing dependencies == way too hard Q: Which of these do you find frustrating What's a dependency bug? Missing interfaces: fangorn.cxx:2:10: fatal error: jsonlog/core.hxx: No such file or directory This could be caused by other root problems! Pain: What's a dependency bug?

Next ..... 21 6. Developing with Spring Boot ..... 23 6.1. Build Systems ..... 23 6.1.1. Dependency Management ..... 23 6.1.2. Maven ..... 23 6.1.3. Gradle ..... 23 6.1.4. Ant ..... 24 6 ... 32 6.4.2. Disabling Specific Auto-configuration Classes ..... 32 6.5. Spring Beans and Dependency Injection ..... 33 6.6. Using the @SpringBootApplication Annotation ..... 35 6.7. Running Your 226 7.10.3. Kotlin API ..... 226 runApplication ..... 226 Extensions ..... 227 7.10.4. Dependency management ..... 227 7.10.5. @ConfigurationProperties ..... 227 7.10.6. Testing ..... 228

What to Read Next ..... 22 III. Using Spring Boot ..... 23 13. Build Systems ..... 24 13.1. Dependency Management ..... 24 13.2. Maven ..... 24 Inheriting the Starter Parent ..... 25 Using ..... 36 16.2. Disabling Specific Auto-configuration Classes ..... 36 17. Spring Beans and Dependency Injection ..... 37 18. Using the @SpringBootApplication Annotation ..... 38 19. Running Your ... 188 48.3. Kotlin API ..... 189 runApplication ..... 189 Extensions ..... 189 48.4. Dependency management ..... 189 48.5. @ConfigurationProperties ..... 190 48.6. Testing ..... 190 48

Creating an executable jar 12. What to read next III. Using Spring Boot 13. Build systems Dependency management Maven Inheriting the starter parent Using Spring Boot without the parent Gradually replacing auto-configuration Disabling specific auto-configuration 17. Spring Beans and dependency injection 18. Using the @SpringBootApplication annotation 19. Running your application Running "grab" coordinates Default import statements Automatic main method Custom dependency management Testing your code Applications with multiple source files Packaging your application

Next ..... 20 6. Developing with Spring Boot ..... 22 6.1. Build Systems ..... 22 6.1.1. Dependency Management ..... 22 6.1.2. Maven ..... 22 6.1.3. Gradle ..... 22 6.1.4. Ant ..... 23 6 Auto-configuration Classes ..... 31 6.4.3. Auto-configuration Packages ..... 31 6.5. Spring Beans and Dependency Injection ..... 32 6.6. Using the @SpringBootApplication Annotation ..... 34 6.7. Running Your 228 7.11.3. Kotlin API ..... 229 runApplication ..... 229 Extensions ..... 229 7.11.4. Dependency management ..... 230 7.11.5. @ConfigurationProperties ..... 230 7.11.6. Testing ..... 230

Next ..... 20 6. Developing with Spring Boot ..... 22 6.1. Build Systems ..... 22 6.1.1. Dependency Management ..... 22 6.1.2. Maven ..... 22 6.1.3. Gradle ..... 22 6.1.4. Ant ..... 23 6 Auto-configuration Classes ..... 31 6.4.3. Auto-configuration Packages ..... 31 6.5. Spring Beans and Dependency Injection ..... 32 6.6. Using the @SpringBootApplication Annotation ..... 34 6.7. Running Your 228 7.11.3. Kotlin API ..... 229 runApplication ..... 229 Extensions ..... 229 7.11.4. Dependency management ..... 230 7.11.5. @ConfigurationProperties ..... 230 7.11.6. Testing ..... 230

. 1.2. Usage scenarios ..... 2. Background information ..... 2.1. Inversion of Control / Dependency Injection ..... 3. Beans, BeanFactory and the ApplicationContext ..... 3.1. Introduction . 3.2.5. To singleton or not to singleton ..... 3.3. Properties, collaborators, autowiring and dependency checking ..... 3.3.1. Setting bean properties and collaborators ..... 3.3.2. Constructor Argument 23.2. Integration testing ..... 265 23.2.1. Context management and caching ..... 266 23.2.2. Dependency Injection of test class instances ..... 266 23.2.3. Transaction management ..... 266 23.2.4

. 1.2. Usage scenarios ..... 2. Background information ..... 2.1. Inversion of Control / Dependency Injection ..... 3. Beans, BeanFactory and the ApplicationContext ..... 3.1. Introduction . 3.2.5. To singleton or not to singleton ..... 3.3. Properties, collaborators, autowiring and dependency checking ..... 3.3.1. Setting bean properties and collaborators ..... 3.3.2. Constructor Argument 21.2. Integration testing ..... 222 21.2.1. Context management and caching ..... 223 21.2.2. Dependency Injection of test class instances ..... 223 21.2.3. Transaction management ..... 223 21.2.4

. 1.2. Usage scenarios ..... 2. Background information ..... 2.1. Inversion of Control / Dependency Injection ..... 3. Beans, BeanFactory and the ApplicationContext ..... 3.1. Introduction . 3.2.5. To singleton or not to singleton ..... 3.3. Properties, collaborators, autowiring and dependency checking ..... 3.3.1. Setting bean properties and collaborators ..... 3.3.2. Constructor Argument Spring Framework The Core package is the most fundamental part of the framework and provides the Dependency Injection features allowing you to manage bean container functionality. The basic concept here