Add specifying components by supertype

source/poodinis/context.d

@@ -28,12 +28,30 @@ class ApplicationContext {
 */
 struct Component {}
 
+/**
+* This annotation allows you to specify by which super type the component should be registered. This
+* enables you to use type-qualified alternatives for dependencies.
+*/
+struct RegisterByType(Type) {
+	Type type;
+}
+
 public void registerContextComponents(ApplicationContextType : ApplicationContext)(ApplicationContextType context, shared(DependencyContainer) container) {
-	import std.stdio;
 	foreach (member ; __traits(allMembers, ApplicationContextType)) {
 		static if (hasUDA!(__traits(getMember, context, member), Component)) {
 			auto factoryMethod = &__traits(getMember, context, member);
-			auto registration = container.register!(ReturnType!factoryMethod);
+			Registration registration = null;
+
+			foreach(attribute; __traits(getAttributes, __traits(getMember, context, member))) {
+				static if (is(attribute == RegisterByType!T, T)) {
+					registration = container.register!(typeof(attribute.type), ReturnType!factoryMethod);
+				}
+			}
+
+			if (registration is null) {
+				registration = container.register!(ReturnType!factoryMethod);
+			}
+
 			registration.instanceFactory = new InstanceFactory(registration.instanceType, CreatesSingleton.yes, null, factoryMethod);
 		}
 	}

test/poodinis/contexttest.d

@@ -11,6 +11,14 @@ import std.exception;
 
 version(unittest) {
 
+	interface Fruit {
+		string getShape();
+	}
+
+	interface Animal {
+		string getYell();
+	}
+
 	class Banana {
 		public string color;
 
@@ -21,6 +29,24 @@ version(unittest) {
 
 	class Apple {}
 
+	class Pear : Fruit {
+		public override string getShape() {
+			return "Pear shaped";
+		}
+	}
+
+	class Rabbit : Animal {
+		public override string getYell() {
+			return "Squeeeeeel";
+		}
+	}
+
+	class Wolf : Animal {
+		public override string getYell() {
+			return "Wooooooooooo";
+		}
+	}
+
 	class TestContext : ApplicationContext {
 
 		@Component
@@ -31,6 +57,24 @@ version(unittest) {
 		public Apple apple() {
 			return new Apple();
 		}
+
+		@Component
+		@RegisterByType!Fruit
+		public Pear pear() {
+			return new Pear();
+		}
+
+		@Component
+		@RegisterByType!Animal
+		public Rabbit rabbit() {
+			return new Rabbit();
+		}
+
+		@Component
+		@RegisterByType!Animal
+		public Wolf wolf() {
+			return new Wolf();
+		}
 	}
 
 	//Test register component registrations from context
@@ -51,4 +95,26 @@ version(unittest) {
 		assertThrown!ResolveException(container.resolve!Apple);
 	}
 
+	//Test register component by base type
+	unittest {
+		shared(DependencyContainer) container = new DependencyContainer();
+		auto context = new TestContext();
+		context.registerContextComponents(container);
+		auto instance = container.resolve!Fruit;
+		assert(instance.getShape() == "Pear shaped");
+	}
+
+	//Test register components with multiple candidates
+	unittest {
+		shared(DependencyContainer) container = new DependencyContainer();
+		auto context = new TestContext();
+		context.registerContextComponents(container);
+
+		auto rabbit = container.resolve!(Animal, Rabbit);
+		assert(rabbit.getYell() == "Squeeeeeel");
+
+		auto wolf = container.resolve!(Animal, Wolf);
+		assert(wolf.getYell() == "Wooooooooooo");
+	}
+
 }