AOP Spring @AfterReturning not working as expected

Question

I am learning AOP spring and trying out some examples. Regarding @AfterReturning,what i have understand is that the method is called only if the target is returned successfully and which match the pointcut. However in my case as shown below i have a pointcut that defines all method that returns a String only but it is calling all the void method and also the method which return a String.

My Advice:

@AfterReturning(value= "execution(*  com.aop..CustomerServiceImpl.*(..))",
        returning= "string")
public void returnStringPointcut(JoinPoint joinPoint,String string){

    System.out.println("logAfter() is running!");
    System.out.println("String : " + string);
    System.out.println("hijacked : " + joinPoint.getSignature().getName());
    System.out.println("******");

}

Please find below my Impl class below:

public void addCustomer() {
    // TODO Auto-generated method stub

}

public String getCustomer() {
    // TODO Auto-generated method stub
    return "string";
}

public boolean deleteCustomer() {
    // TODO Auto-generated method stub
    return false;
}
public void addCustomerAppended() {
    // TODO Auto-generated method stub

}

public void deleteCustomerVoid() {
    // TODO Auto-generated method stub
    //return false;
}

Please find below my MainApp class:

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

    {
        ApplicationContext context = new ClassPathXmlApplicationContext(
                "Spring-Customer.xml");

        CustomerService cs =  context.getBean("customerBo", CustomerService.class);
        cs.addCustomer();
        cs.addCustomerAppended();
        cs.deleteCustomer();
        cs.deleteCustomerVoid();
        cs.getCustomer();


    }
}

I was expecting that only getCustomer() will be called since it is the only one that returns a string but instead i get the following output in my console when i run the application:

logAfter() is running!
String : null
hijacked : addCustomer
******
logAfter() is running!
String : null
hijacked : addCustomerAppended
******
logAfter() is running!
String : null
hijacked : deleteCustomerVoid
******
logAfter() is running!
String : string
hijacked : getCustomer
******

Please find my pom.xml below:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.aop.spring</groupId>
    <artifactId>SpringAopOnly</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>SpringAopOnly</name>
    <url>http://maven.apache.org</url>
    <properties>
        <spring.version>3.0.5.RELEASE</spring.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.8.2</version>
            <scope>test</scope>
        </dependency>

        <!-- Spring 3 dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Spring AOP  -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>

            <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.6.11</version>
        </dependency>

        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.6.11</version>
            </dependency>

    </dependencies>
</project>

Please find my config file below:

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
    http://www.springframework.org/schema/aop 
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">

    <!-- <aop:aspectj-autoproxy />  -->
    <aop:aspectj-autoproxy>
    <aop:include name ="logAspect" />
    </aop:aspectj-autoproxy>

    <bean id="customerBo" class="com.aop.impl.CustomerServiceImpl" />

    <!-- Aspect -->
    <bean id="logAspect" class="com.aop.aspect.CustomerAspect" />

</beans>

Any idea why it is calling the void method please?

I have also tried to change the afterReturning from String to boolean then i get the expected result that is only deleteCustomer is called since it returns a boolean.

Thanks a lot in advance for response.

Answer 1

The returning argument only specifies

The name of the argument in the advice signature to bind the returned value to

Your actual pointcut

@AfterReturning(value= "execution(*  com.aop..CustomerServiceImpl.*(..))",
    returning= "string")

is specifying

execution(* com.aop..CustomerServiceImpl.*(..))

where * matches all return types.

You should change it to

execution(java.lang.String com.aop..CustomerServiceImpl.*(..))

if you want only methods declared as returning a String.

---

Both the return type in the annotation value expression and the method parameter type play a role in what methods are going to be advised. For example

@AfterReturning(value = "execution(String com.aop..CustomerServiceImpl.*(..))", returning = "random")
public void returnStringPointcut(JoinPoint joinPoint, Integer random) {

won't match anything.

---

On a side note, you should consider upgrading your Spring and aspectj versions. I think a lot of these issues are either fixed or the overall libraries are more stable.