Use of BeanPostProcessor

[anjibman]

Hi All,

I am trying to understand the application of BeanPostProcessor. I understood that postProcessBeforeInitialization() and postProcessAfterInitialization() methods are used to plugg in my code after Spring container does its.
What I don't understand is if I have multiple beans can I have customized process for each bean?

I have following codes;

public class HelloWorld {
	private String message;

	   public void setMessage(String message){
	      this.message  = message;
	   }

	   public void getMessage(){
	      System.out.println("Your Message : " + message);
	   }

	   public void init(){
	      System.out.println("Bean is going through init.");
	   }

	   public void destroy(){
	      System.out.println("Bean will destroy now.");
	   }

}

public class HelloWorld1 {
	private String message;

	   public void setMessage(String message){
	      this.message  = message;
	   }

	   public void getMessage(){
	      System.out.println("Your Message1 : " + message);
	   }

	   public void init1(){
	      System.out.println("Bean1 is going through init.");
	   }

	   public void destroy1(){
	      System.out.println("Bean1 will destroy now.");
	   }

}

public class InitHelloWorld implements BeanPostProcessor {

    public Object postProcessBeforeInitialization(Object bean,
            String beanName) throws BeansException {
        System.out.println("BeforeInitialization : " + beanName);
        return bean;  // you can return any other object as well
    }

    public Object postProcessAfterInitialization(Object bean,
            String beanName) throws BeansException {
        System.out.println("AfterInitialization : " + beanName);
        return bean;  // you can return any other object as well
    }
}

<bean id="helloWorld" class="com.anjib.beans.HelloWorld"
       init-method="init" destroy-method="destroy">
       <property name="message" value="Hello World!"/>
   </bean>
   
   <bean id="helloWorld1" class="com.anjib.beans.HelloWorld1"
       init-method="init1" destroy-method="destroy1">
       <property name="message" value="Hello World1!"/>
   </bean>

   <bean class="com.anjib.beans.InitHelloWorld" />

public class MainApp {
    public static void main(String[] args) {

	      AbstractApplicationContext context = 
	                          new ClassPathXmlApplicationContext("Beans.xml");

	      HelloWorld obj = (HelloWorld) context.getBean("helloWorld");
	      obj.getMessage();
              HelloWorld1 obj1 = (HelloWorld1) context.getBean("helloWorld1");
	      obj1.getMessage();
	      context.registerShutdownHook();
	   }

}

This gives me following output:

BeforeInitialization : helloWorld
Bean is going through init.
AfterInitialization : helloWorld
BeforeInitialization : helloWorld1
Bean1 is going through init.
AfterInitialization : helloWorld1
Your Message : Hello World!
Your Message1 : Hello World1!
Bean1 will destroy now.
Bean will destroy now.

What I want is use InitHelloWorld for HelloWorld bean and some new InitHelloWorld1 for HelloWorld1 bean. Is that possible for I am missing fundamental concept here.

Any help is appreciated.

Thanks

[objectamit]

BeanPostProcessor is applied on each bean for each bean declaration in the spring context. You can't control that. For your use-case, I would suggest using spring-aspects and configure different aspects encapsulating the logic you would place inside different BeanPostProcessors. Then the advice that you apply need to be such that it applies one aspect for a certain class while other aspect for any other class.