I'm trying to run a little annotation over function that will log before and after the method execution.
What I've done: (all classes are under src/main/kotlin
)
Annotation class
@Target(AnnotationTarget.FUNCTION)
@Retention(AnnotationRetention.RUNTIME)
annotation class LogMe
Aspect class
import org.aspectj.lang.JoinPoint
import org.aspectj.lang.ProceedingJoinPoint
import org.aspectj.lang.annotation.Around
import org.aspectj.lang.annotation.Aspect
@Aspect
abstract class Aspect {
@Around("@annotation(LogMe) && execution(* *(..))")
fun logMe(joinPoint: ProceedingJoinPoint): Any {
beforeExecution(joinPoint)
afterExecution(joinPoint)
return joinPoint.proceed()
}
private fun beforeExecution(joinPoint: JoinPoint) {
println("[${joinPoint.signature.name} has started its execution]")
}
private fun afterExecution(joinPoint: JoinPoint) {
println("[${joinPoint.signature.name} has ended its execution]")
}
}
Foo class with annotated method
class Foo {
@LogMe
fun yourMethodAround() {
println("Executing foo.yourMethodAround()")
}
}
main file
fun main(args: Array<String>) {
val foo = Foo()
foo.yourMethodAround()
}
my POM.xml (cut version)
...
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
<version>1.3.40</version>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-reflect</artifactId>
<version>1.3.40</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.9.4</version>
</dependency>
<!-- TEST -->
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test</artifactId>
<version>1.3.40</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test-junit</artifactId>
<version>1.3.40</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<sourceDirectory>src/main/kotlin</sourceDirectory>
<testSourceDirectory>src/test/kotlin</testSourceDirectory>
<plugins>
<plugin>
<artifactId>kotlin-maven-plugin</artifactId>
<configuration>
<jvmTarget>1.8</jvmTarget>
</configuration>
<groupId>org.jetbrains.kotlin</groupId>
<version>1.3.40</version>
<executions>
<execution>
<id>kapt</id>
<goals>
<goal>kapt</goal>
</goals>
</execution>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals> <goal>compile</goal> </goals>
</execution>
<execution>
<id>test-compile</id>
<phase>test-compile</phase>
<goals> <goal>test-compile</goal> </goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>com.jcabi</groupId>
<artifactId>jcabi-maven-plugin</artifactId>
<version>0.14.1</version>
<executions>
<execution>
<goals>
<goal>ajc</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.0</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>MainKt</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.4.3</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
When I basically run this main, what I'm obtaining is the println that it's into my Foo class method:
Executing foo.yourMethodAround()
But I'm not getting the before and after execution prinln that I was expecting from the Aspect class.
Does any of you ever faced this issue before? This is struggling me, because I can't understand what's going on here.
Disclaimer:
Now some things are not okay in your aspect:
abstract
, otherwise no instance can be created.void
methods it must be able to return null
, so the Kotlin return type should be Any?
proceed()
in between the before and after log messages, otherwise the log output will be wrong.@annotation(de.scrum_master.app.LogMe)
Aspect
, i.e. the same name as the @Aspect
annotation, just in another package, is kind of ugly. You should rename it.For me this works nicely:
package de.scrum_master.aspect
import org.aspectj.lang.JoinPoint
import org.aspectj.lang.ProceedingJoinPoint
import org.aspectj.lang.annotation.Around
import org.aspectj.lang.annotation.Aspect
@Aspect
class LogAspect {
@Around("@annotation(de.scrum_master.app.LogMe) && execution(* *(..))")
fun logMe(joinPoint: ProceedingJoinPoint): Any? {
beforeExecution(joinPoint)
val result = joinPoint.proceed()
afterExecution(joinPoint)
return result
}
private fun beforeExecution(joinPoint: JoinPoint) {
println("[${joinPoint.signature.name} has started its execution]")
}
private fun afterExecution(joinPoint: JoinPoint) {
println("[${joinPoint.signature.name} has ended its execution]")
}
}
Besides, maybe you also should configure the Jcabi plugin to language level Java 8. It works without it here, but maybe it is better depending on which language features you use:
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
My console after mvn clean verify
looks like this:
$ java -jar target/so-aj-kotlin-56890630-1.0-SNAPSHOT.jar
[yourMethodAround has started its execution]
Executing foo.yourMethodAround()
[yourMethodAround has ended its execution]
My IDE IntelliJ IDEA does not quite pick up the binary weaving stuff because it does not know Jcabi, only AspectJ Maven. So I just configured the project to delegate compilation to Maven:
Then the log output is the same when running the application from IDEA directly.