add DI using java code without using xml configurations

Author: aotantawy

inversion-of-control-and-dependency-injection/injection-using-java-code/.gitignore

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+/bin/

inversion-of-control-and-dependency-injection/injection-using-java-code/src/cars.properties

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+car1.model = Tesla model 3

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/spring/App.java

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+package com.spring;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+import com.utilities.vehicle.Vehicle;
+
+/*
+ * For learning purposes:
+ * 	1. I use constructor injection using annotations to create bicycle bean 
+ * 	2. I use setter injection using java code configuration to create car bean
+ * but this is not best practice in this situation
+ */
+
+public class App {
+
+	public static void main(String[] args) {
+		AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(
+				JavaConfig.class);
+
+		Vehicle bicycle = applicationContext.getBean("bicycle", Vehicle.class);
+		Vehicle car = applicationContext.getBean("car", Vehicle.class);
+
+		System.out.println("===============");
+
+		System.out.println(bicycle.getFullDescription());
+		System.out.println(bicycle.getMechanicRole());
+
+		System.out.println("===============");
+
+		System.out.println(car.getFullDescription());
+		System.out.println(car.getMechanicRole());
+
+		System.out.println("===============");
+
+		applicationContext.close();
+
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/spring/JavaConfig.java

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+package com.spring;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.PropertySource;
+
+import com.utilities.mechanic.CarMechanic;
+import com.utilities.mechanic.Mechanic;
+import com.utilities.vehicle.Car;
+import com.utilities.vehicle.Vehicle;
+
+@Configuration
+@ComponentScan("com.utilities.mechanic")
+@ComponentScan("com.utilities.vehicle")
+@PropertySource("classpath:cars.properties")
+public class JavaConfig {
+
+	@Bean
+	public Mechanic carMechanic() {
+		return new CarMechanic();
+	}
+
+	@Bean
+	public Vehicle car() {
+		Car carBean = new Car();
+		carBean.setMechanic(carMechanic());
+		return carBean;
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/mechanic/BicycleMechanic.java

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+package com.utilities.mechanic;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class BicycleMechanic implements Mechanic {
+
+	@Override
+	public String getRole() {
+		return "I'm a bicycle mechanic";
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/mechanic/CarMechanic.java

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+package com.utilities.mechanic;
+
+public class CarMechanic implements Mechanic {
+
+	@Override
+	public String getRole() {
+		return "I'm a car mechanic";
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/mechanic/Mechanic.java

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+package com.utilities.mechanic;
+
+public interface Mechanic {
+	String getRole();
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/vehicle/Bicycle.java

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+package com.utilities.vehicle;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+import com.utilities.mechanic.Mechanic;
+
+@Component
+public class Bicycle implements Vehicle {
+
+	private double size;
+	private Mechanic mechanic;
+
+	public Bicycle(@Value("15") double size, @Autowired @Qualifier("bicycleMechanic") Mechanic mechanic) {
+		this.size = size;
+		this.mechanic = mechanic;
+	}
+
+	@Override
+	public String getFullDescription() {
+		return String.format("Bicycle size: %f", size);
+	}
+
+	@Override
+	public String getMechanicRole() {
+		return mechanic.getRole();
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/vehicle/Car.java

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+package com.utilities.vehicle;
+
+import org.springframework.beans.factory.annotation.Value;
+
+import com.utilities.mechanic.Mechanic;
+
+public class Car implements Vehicle {
+
+	@Value("${car1.model}")
+	String model;
+	Mechanic mechanic;
+
+	public void setMechanic(Mechanic mechanic) {
+		this.mechanic = mechanic;
+	}
+
+	@Override
+	public String getFullDescription() {
+		return String.format("Car Model: %s", model);
+	}
+
+	@Override
+	public String getMechanicRole() {
+		return mechanic.getRole();
+	}
+
+}

inversion-of-control-and-dependency-injection/injection-using-java-code/src/com/utilities/vehicle/Vehicle.java

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+package com.utilities.vehicle;
+
+public interface Vehicle {
+	String getFullDescription();
+
+	String getMechanicRole();
+}