Spring Rmi Integration

[Ashwin Sridhar]

Hi All,

I am working on Spring-RMI integration, following what is provided in "Spring in Action" book.

I want to know should we have to re-create the interfaces & domain Objects in client side as well. (That definitely doesn't look the way)

I get a compile time exception stating the server side interfaces & domain Objects are not found.

Any help is appreciated.

Server Side Code :

Application.java

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


public class Application {
	public static void main(String[] args){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("rmi-spring-configuration.xml");
		ctx.getBean("employeeService");
	}
}

Employee.java (Domain)

package com.pack.domain;

import java.io.Serializable;

public class Employee implements Serializable {
	private String name;
	private String empId;
	private int age;
	
	public Employee(){}
	public Employee(String name , String empId , int Age){
		this.name = name;
		this.empId = empId;
		this.age=Age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getEmpId() {
		return empId;
	}
	public void setEmpId(String empId) {
		this.empId = empId;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
}

Interface

package com.pack.inter;

import com.pack.domain.Employee;

public interface EmployeeInterface {
	public void addEmployee(Employee emp);
	public void deleteEmployee(Employee emp);
}

Implementation

package com.pack.impl;

import com.pack.domain.Employee;
import com.pack.inter.EmployeeInterface;


public class EmployeeImpl implements EmployeeInterface {

	
	
	@Override
	public void addEmployee(Employee emp) {
		// TODO Auto-generated method stub
		System.out.println("Added Employee.....");

	}

	@Override
	public void deleteEmployee(Employee emp) {
		// TODO Auto-generated method stub
		System.out.println("Deleted Employee.....");
	}

}

Server side Configuration 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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
	
   <bean id="employeeService" class="com.pack.impl.EmployeeImpl"/>
   
   <bean id="test" class="org.springframework.remoting.rmi.RmiServiceExporter">
   		<property name="serviceName" value="Employee-Service" />
   		<property name="service" ref="employeeService"></property>
   		<property name="serviceInterface" value="com.pack.inter.EmployeeInterface"></property>
   		<property name="registryPort" value="1234"/>
   </bean>

</beans>

Client Side Code

Application.java

package com;

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

import com.pack.domain.Employee;
import com.pack.inter.EmployeeInterface;
public class ApplicationClient {
	public static void main(String[] args){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("rmi-spring-configuration.xml");
		EmployeeInterface obj = (EmployeeInterface) ctx.getBean("employeeService");
		obj.addEmployee(new Employee("Ashw","asj",12));
		
	}
}

Client Side configuration 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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
	
    <bean class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
    	<property name="serviceUrl" value="rmi://localhost:1234/Employee-Service"/>
    	<property name="serviceInterface" value="com.pack.inter.EmployeeInterface"></property>
    </bean>
</beans>

Regards,
Ashwin

[Mark Spritzler]

OK. This actually comes down to how core Java works.

If you have code that uses other classes, those classes always have to be in the classpath.

So if I am a client, and I use your Domain object in my code, then the domain object class better be in my client side classpath. Same with if I use your interface, then the Interface better be in my classpath.

Mark

[Ashwin Sridhar]

If I understand you correctly, should I have the interface and domain Object in my client side as well ?

Then any change on server, requires appropriate changes in the client as well ?

[Ashwin Sridhar]

Having interfaces & domain on the classpath of the client makes a very tight coupling. Is this not a drawback of RMI ?

Or is this the place where Webservices over powers RMI ?

[Mark Spritzler]

Ashwin Sridhar wrote:If I understand you correctly, should I have the interface and domain Object in my client side as well ?

Then any change on server, requires appropriate changes in the client as well ?

You should have whatever class files you need and use in any Java code running. Regardless.

I run java from the command line, and it runs some Java code, any class that that code uses has to have that class in the classpath. Plain and simple. Trying to figure out client side server side it just adding complexity to the question.

If both the server side and the client side are both using a class, then that class has to be in the classpath for both sides. not because it is client and server, but because each is using the class in their own jvm. That is why this is just a Java question and not related to Spring.

Hope that helps clear things up for you.

Mark