Maven + AspectJ - all steps to configure it

Question

I have a problem with applying aspects to my maven project. Probably I am missing something, so I\'ve made a list of steps. Could you please check if it is correct?

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Answer 1

I traced some of your older questions to try to find out what you actually are trying to do. I have come up with the following structure and code and for me it works well.

$ tree .
.
├── pom.xml
├── ProjectA
|   ├── pom.xml
|   └── src
|       └── main
|           └── aspect
|               └── com
|                   └── stackoverflow
|                       └── aspects
|                           ├── AspectL.java
|                           └── Trace.aj
└── ProjectB
    ├── pom.xml
    └── src
        └── main
            └── java
                └── com
                    └── stackoverflow
                        └── App.java

pom.xml

    4.0.0

    org.stackoverflow
    Q12423965
    pom
    1.0-SNAPSHOT

    ${project.artifactId}-${project.version}

    
        UTF-8
        1.6
        1.6
    

    
        ProjectA
        ProjectB
    

    
        
            
                org.stackoverflow
                Q12423965-ProjectA
                ${project.version}
            
        
    

    
        
            
                
                    org.codehaus.mojo
                    aspectj-maven-plugin
                    1.4
                    
                        
                            
                                compile
                                test-compile
                            
                        
                    
                    
                        ${maven.compiler.source}
                        ${maven.compiler.target}
                    
                
                
                    org.apache.maven.plugins
                    maven-compiler-plugin
                    2.5.1
                    
                        ${maven.compiler.source}
                        ${maven.compiler.target}
                    
                
            
        
    

ProjectA/pom.xml

    4.0.0

    
        org.stackoverflow
        Q12423965
        1.0-SNAPSHOT
    

    Q12423965-ProjectA

    ${project.artifactId}-${project.version}

    
        
            org.aspectj
            aspectjrt
            1.6.11
        
    

    
        
            
                org.codehaus.mojo
                aspectj-maven-plugin
            
        
    

I have created two differenct aspects. One that uses @AspectJ annotations and another one that is defined as a classic AspectJ aspect.

AspectL.java

package com.stackoverflow.aspects;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;

/**
 * @author maba, 2012-09-18
 */
@Aspect
public class AspectL {

    @Pointcut("execution(* main(..))")
    public void defineEntryPoint() {
    }

    @Before("defineEntryPoint()")
    public void aaa(JoinPoint joinPoint) {
        System.out.println("aspect before");
    }

    @After("defineEntryPoint()")
    public void bbb(JoinPoint joinPoint) {
        System.out.println("aspect after");
    }
}

Trace.aj

package com.stackoverflow.aspects;

public aspect Trace {
    pointcut publicMethodExecuted(): execution(public !static * *(..));

    after(): publicMethodExecuted() {
        System.out.printf("Enters on method: %s. \n", thisJoinPoint.getSignature());

        Object[] arguments = thisJoinPoint.getArgs();
        for (int i =0; i < arguments.length; i++){
            Object argument = arguments[i];
            if (argument != null){
                System.out.printf("With argument of type %s and value %s. \n", argument.getClass().toString(), argument);
            }
        }
        System.out.printf("Exits method: %s. \n", thisJoinPoint.getSignature());
    }
}

Those two files are part of the ProjectA module and are part of a jar.

Now we want to use these aspects and weave them into the code of ProjectB.

ProjectB/pom.xml

    4.0.0

    
        org.stackoverflow
        Q12423965
        1.0-SNAPSHOT
    

    Q12423965-ProjectB

    ${project.artifactId}-${project.version}

    
        
            org.aspectj
            aspectjrt
            1.6.11
        
        
            org.stackoverflow
            Q12423965-ProjectA
        
    

    
        
            
                org.codehaus.mojo
                aspectj-maven-plugin
                
                    
                        
                            org.stackoverflow
                            Q12423965-ProjectA
                        
                    
                
            
            
                org.codehaus.mojo
                exec-maven-plugin
                1.2.1
                
                    
                        
                            java
                        
                    
                
                
                    com.stackoverflow.App
                
            
        
    

App.java

package com.stackoverflow;

/**
 * @author maba, 2012-09-17
 */
public class App {

    public void hello(String name) {
    }

    public static void main(String[] args) {
        App app = new App();
        app.hello("world");
    }
}

I build everything from top pom:

mvn clean install

And then go into the ProjectB directory and run the app:

mvn exec:java

The result is:

aspect before
Enters on method: void com.stackoverflow.App.hello(String). 
With argument of type class java.lang.String and value world. 
Exits method: void com.stackoverflow.App.hello(String). 
aspect after

So to conclude both aspects are working and the maven setup also works.