Spring lookup-method Example

App.java

package com.rajesh.learnjava.controller;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.rajesh.learnjava.bean.ControllerClass;

public class App {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(
"applicationcontext.xml");

ControllerClass helloWorld = (ControllerClass) context.getBean("controller");

System.out.println("1st service : " + helloWorld.getServiceClass().getStr());



ControllerClass helloWorld2 = (ControllerClass) context.getBean("controller");

System.out.println("1st service : " + helloWorld2.getServiceClass().getStr());



System.out.println("##########  Below is the service call with lookup-method option in spring and see the results ##########");


ControllerClass controller = (ControllerClass) context.getBean("controller");

System.out.println("2nd service : " + controller.getServiceClasswithLookupMethod().getStr());

ControllerClass controller2 = (ControllerClass) context.getBean("controller");

System.out.println("2nd service : " + controller2.getServiceClasswithLookupMethod().getStr());

}
}

ControllerClass.java

package com.rajesh.learnjava.bean;

public class ControllerClass {

ServiceClass serviceClass;

ServiceClasswithLookupMethod serviceClasswithLookupMethod;

public ServiceClass getServiceClass() {

return serviceClass;

}

public void setServiceClass(ServiceClass serviceClass) {

this.serviceClass = serviceClass;

}

public ServiceClasswithLookupMethod getServiceClasswithLookupMethod() {

return serviceClasswithLookupMethod;

}

public void setServiceClasswithLookupMethod(

ServiceClasswithLookupMethod serviceClasswithLookupMethod) {

this.serviceClasswithLookupMethod = serviceClasswithLookupMethod;

}

}

ServiceClass.java

package com.rajesh.learnjava.bean;

public class ServiceClass {

private int counter;

public String getStr() {

return " counter is:" + (++counter);

}

}

applicationContext.xml

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

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

xmlns:ws=" https://jax-ws.java.net/spring/core"

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

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

https://jax-ws.java.net/spring/core 

    https://jax-ws.java.net/spring/core.xsd

    https://jax-ws.java.net/spring/servlet

    https://jax-ws.java.net/spring/servlet.xsd">

    

    <bean id="controller" class="com.rajesh.learnjava.bean.ControllerClass" scope="singleton">

<property name="serviceClass" ref="serviceClass" />

<lookup-method name="getServiceClasswithLookupMethod" bean="serviceClasswithLookupMethod"/>

</bean>

<bean id="serviceClass" class="com.rajesh.learnjava.bean.ServiceClass" scope="prototype">

</bean>

<bean id="serviceClasswithLookupMethod" class="com.rajesh.learnjava.bean.ServiceClasswithLookupMethod" scope="prototype">

</bean>

<bean id="myBean" class="com.mycompany.MyPrototypeBean" scope="prototype">

   <aop:scoped-proxy/>

 </bean>

</beans>

Below is the output of the program App.java If you observer the output closely, the first two lines, the count is incremented from 1 to 2 because we are getting same serviceClass instance in both the cases 

whereas we are getting counter value as 1 and 1 for the 2nd set of statements. This is because, we are getting new instance of ServiceClass (using the lookup-method) each time into the Controller class even though COntroller class in defined with singleton scope.

1st service :  counter is:1

1st service :  counter is:2

##########  Below is the service call with lookup-method option in spring and see the results ##########

2nd service :  counter is:1

2nd service :  counter is:1