Inversion of Control - Dependency Injection

 Using net beans 8.02 and java 8

1. create java project 

2. create 3 class files 

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2.1 Car File 
    public class Car {

    private String make;
    private String model;
    private int year;
    private Engine engine;

/*Dependency Injection by Constructor*/
public Car(String make,String model,int year,Engine engine){
    this.engine=engine;
    this.model=model;
    this.make=make;
    this.year=year;
   
}
   
public void setMake(String make){
    this.make=make;
}

public String getMake(){
    return make;
}

public void setModel(String model){
    this.model=model;
}

public String getModel(){
    return model;
}

public void setYear(int year){
    this.year=year;
}

public int getYear(){
    return year;
}

public void setEngine(Engine engine){
    this.engine=engine;
}

public Engine getEngine(){
    return engine;
}
public void showCarDetails(){
    System.out.println("Car Details:");
    System.out.println("Make="+getMake());
    System.out.println("Model="+getModel());
    System.out.println("Year="+getYear());
    engine.showEngineDetails();
    }

}   

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2.2 Engne.java

public class Engine {

    private String engine;

    private String maxPower;

    private String engineLocation;

   

    /*Dependency Injection by Constructor*/

    public Engine(String engine,String maxPower, String engineLocation){

        this.engine=engine;

        this.maxPower=maxPower;

        this.engineLocation=engineLocation;

               

    }

    public void setEngine(String engine){

        this.engine=engine;

    }

   

    public String getEngine(){

        return engine;

    }

   

    public void setMaxPower(String maxPower){

        this.maxPower=maxPower;

    }

   

    public String getMaxPower(){

        return maxPower;

    }

    public void setEngineLocation(String engineLocation){

        this.engineLocation=engineLocation;

    }

   

    public String getEngineLocation(){

        return engineLocation;

    }

   

    public void showEngineDetails(){

        System.out.println("****Engine Details****");

        System.out.println("Engine="+getEngine());

        System.out.println("Maximum Power="+getMaxPower());

        System.out.println("Engine Location="+getEngineLocation());

    }

}

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2.3 MainApp.java

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainApp {

     public static void main(String args[]){

        ApplicationContext ctx=new ClassPathXmlApplicationContext("resources/ApplicationContext.xml");

        Car car=(Car)ctx.getBean("myCar");

        car.showCarDetails();

    }

}

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create folder in root called resources

create a file ApplicationContext.xml in the resource folder 

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ApplicationContext.xml file 

<?xml version="1.0" encoding="UTF-8"?>

<beans

    xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:context="http://www.springframework.org/schema/context"

    xmlns:tx="http://www.springframework.org/schema/tx"

    xmlns:mvc="http://www.springframework.org/schema/mvc"

    xsi:schemaLocation="http://www.springframework.org/schema/mvc 

    http://www.springframework.org/schema/mvc/spring-mvc.xsd

    http://www.springframework.org/schema/beans 

    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

    http://www.springframework.org/schema/context 

    http://www.springframework.org/schema/context/spring-context-3.0.xsd

    http://www.springframework.org/schema/tx 

    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

<bean id="myCar" class="Car">

<!-- Injecting primitive values as Dependencies-->

  <constructor-arg name="make" value="Maruti Suzuki"/>

  <constructor-arg name="model" value="Wagon R"/>

  <constructor-arg name="year" value="2012"/>

<!-- Injecting reference to other bean as Dependency-->

  <constructor-arg name="engine" ref="myEngine"/>

</bean>

<bean id="myEngine" class="Engine">

<!-- Injecting primitive values as Dependencies-->

    <constructor-arg name="engine" value="3664 cc"/>

    <constructor-arg name="maxPower" value="304HP"/>

    <constructor-arg name="engineLocation" value="front"/>

</bean>

</beans>

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include below library files 

05/11/2022  10:57 PM            52,124 commons-logging-1.1.1-api.jar

05/11/2022  10:57 PM           556,590 org.springframework.beans-3.0.6.release.jar

05/11/2022  10:57 PM           382,184 org.springframework.core-3.0.6.release.jar

05/11/2022  10:57 PM           169,752 org.springframework.expression-3.0.6.release.jar

05/11/2022  10:58 PM            53,082 spring-asm-3.0.6.RELEASE.jar

05/11/2022  10:58 PM           670,258 spring-context-3.0.6.RELEASE.jar

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Run main file