Java/Spring/MethodBeforeAdvice

Implements MethodBeforeAdvice To Check Parameters

   <source lang="java">
      

File: context.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"

   "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

 <bean id="afterBean" class="org.springframework.aop.framework.ProxyFactoryBean">
   <property name="target">
     <bean class="MtBean">
       <property name="firstName" value="AAA"/>
     </bean>
   </property>
   <property name="interceptorNames">
     <list>
       <idref bean="nullArgumentsNotAllowedBeforeAdvice"/>
     </list>
   </property>
   <property name="proxyTargetClass" value="true"/>
 </bean>
 <bean id="nullArgumentsNotAllowedBeforeAdvice"
       class="NullArgumentsNotAllowedBeforeAdvice"/>

</beans>

File: Main.java import java.lang.reflect.Method; import org.springframework.aop.MethodBeforeAdvice; import org.springframework.beans.factory.BeanFactory; import org.springframework.beans.factory.xml.XmlBeanFactory; import org.springframework.core.io.ClassPathResource; public class Main {

 public static void main(String[] args) throws Exception {
   BeanFactory beanFactory = new XmlBeanFactory(new ClassPathResource("context.xml"));
   MtBean testBean = (MtBean) beanFactory
       .getBean("afterBean");
   testBean.showValues();
 }

} class MtBean {

 private String firstName;
 public String getFirstName() {
   return this.firstName;
 }
 public void setFirstName(String firstName) {
   this.firstName = firstName;
 }
 public void showValues() {
   System.out.println("First name: " + this.firstName);
 }

} class NullArgumentsNotAllowedBeforeAdvice implements MethodBeforeAdvice {

 public void before(Method method, Object[] arguments, Object target)
     throws Throwable {
   if (arguments == null || arguments.length == 0) {
     return;
   }
   
   for (int i = 0; i < arguments.length; i++) {
     Object argument = arguments[i];
     if (argument == null) {
       throw new IllegalArgumentException(
         "Value for argument [" + i + "] is required but not present " +
         "for method [" + method + "]!"
       );
     }
   }
 }

}

      </source>