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dependency injection in spring

Innocent Iguana answered on March 20, 2024 Popularity 8/10 Helpfulness 4/10

answer dependency injection in spring

dependency injection in spring

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// GameInterface.java
public interface GameInterface {void play();}

// PacmanGame.java (Beans from this class are independent)
@Component
@Primary
public class PacmanGame implements GameInterface {
    @Override
    public void play() {System.out.println("Playing Pacman game...");}
}

// SuperContraGame.java (Beans from this class are independent)
@Component("superContraGame")
public class SuperContraGame implements GameInterface {
    @Override
    public void play() {System.out.println("Playing Super Contra game...");}
}

// GameRunner.java (Beans from this class are dependent on any class that implements GameInterface)
@Component 
public class GameRunner {
    @Autowired // Spring automatically provide the required bean of @Primary(top-priority) class "PacmanGame" and connect to it
    private GameInterface pacmanGame;

    @Autowired // This annotation makes sure instead of programmer, the spring is wiring the connection (Inversion of Control)
    @Qualifier("superContraGame") // Spring automatically provide the bean of class component with name "superContraGame" as argument to it
    private GameInterface superContraGame;

    public void runGames() {
        System.out.println("Running Pacman game:");
        pacmanGame.play();
        System.out.println("Running Super Contra game:");
        superContraGame.play();
    }
}

// Main.java  (This is the main application launcher)
@Configuration
@ComponentScan(basePackages = "your.package.name") // Helps to find where all components are located to set up dependency tree
public class Main {

    public static void main(String[] args) {
        try (var context = new AnnotationConfigApplicationContext(Main.class)) { // Points to itself (Autoonfiguration with component scan)
            GameRunner gameRunner = context.getBean(GameRunner.class);
            gameRunner.runGames();
        }
    }
}

Popularity 8/10 Helpfulness 4/10 Language java

Source: Grepper

Tags: dependency-injection java spring

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Contributed on Mar 20 2024

Innocent Iguana

0 Answers Avg Quality 2/10

dependency injection in spring

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