Following post will explain the java tightly and loosely coupled code.And How to avoid the tightly coupled code By using Spring Dependency Injection
Following link have war file example. play it
Download Dependence Injection Example (War)
This is a web project war import this war to your eclipse and right click on Employee class run the java
To view change the id
ref to oracle to view change
Tightly Coupled Code:
If the one java class completely using the other java class's logic means collaboration.
Example:
class SunMicrosystems {
public void showCompanyName() {
System.out.println("SunMicrosystems");
}
}
/**
Employee calls the
SunMicrosystems's logic . If we change the logic.we must change the java file also.
Employee class always depends the SunMicrosystems is called tightly coupled
*/
class Employee {
SunMicrosystems sun = new SunMicrosystems();
public void workCompany() {
sun.showCompanyName();
}
public static void main(String[] arg) {
Employee emp = new Employee();
emp.workCompany();
}
}
Let We See How to avoid tightly coupled code by
Spring Dependency Injection.
By Introduce the Interface we can avoid the tightly coupled code
Loosely Coupled Code:
package com;
interface Company {
public void showCompanyName();
}
package com;
class Oracle implements Company {
public void showCompanyName() {
System.out.println("Oracle");
}
}
package com;
class SunMicrosystems implements Company {
public void showCompanyName() {
System.out.println("SunMicrosystems");
}
}
package com;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
class Employee {
private Company c;
public void setC(Company c) {
this.c = c;
}
public void showCompany() {
c.showCompanyName();
}
public static void main(String[] arg) {
Resource r = new ClassPathResource("applicationContext.xml");
BeanFactory factory = new XmlBeanFactory(r);
Employee emp = (Employee) factory.getBean("emp");
emp.showCompany();
}
}
/**
In the employee class class the method showCompany(), It in company Interface , Following xml file we can change the
ref attribute itself can desired ,the method call from which class
*/
<?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:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="sun" class="com.SunMicrosystems" />
<bean id="oracle" class="com.Oracle" />
<bean id="emp" class="com.Employee">
<property name="c" ref="sun" />
</bean>
</beans>
