Simply Dependency Manager

This project contains two different implementations of Dependency Injection.

DependencyManagerTyped

This implementation is more like a service locator. It is more performative because it is typed, without the use of reflection.

Works passing the Manager to the constructor of every Business Logic Service.

Example: https://github.com/GustavoHennig/SimpleDependencyManager/blob/master/src/test/java/simpledependecymanager/DependencyManagerTypedTest.java

I found a post that explains the concept better: https://proandroiddev.com/why-service-locator-is-so-unpopular-bbe8678be72c

DependencyManagerReflection

It uses the well known @Inject annotation, the injector will try to create automatically on every attribute with this annotation when the type has constructor without arguments.

This solution was created for simple integration testes, but can be used in large project.

Examples

Examples of how to use (Reflection version).

public class ServiceExample {

    @Inject
    private ServiceToInject serviceToInject;
    private String injectByRule;
}

public class ServiceToInject {
    public int foo() {
        return 1 + 1;
    }
}

Creates the instances automatically

public class DependencyManagerReflectionTest {
    @Test
    public void test() {
        DependencyManagerReflection dependencyManager = new DependencyManagerReflection();

        // Configure an injection rule exception
        String existingInstance = "existingInstance";
        dependencyManager.addRule("injectByRule", String.class, existingInstance);
        
        ServiceExample serviceExample = dependencyManager.get(ServiceExample.class);
        
        assertEquals("must call the method of injected class", 2, serviceExample.callFoo());
        assertSame("must be same instance", existingInstance, serviceExample.getInjectByRule());
    }    
}

Please, see the unit tests of this project for more examples:

https://github.com/GustavoHennig/SimpleDependencyManager/tree/master/src/test/java/simpledependecymanager