AOP

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>at.aydin.academy</groupId>
        <artifactId>02aop-pair</artifactId>
        <version>1.0.0</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <artifactId>aop-modern</artifactId>
    <packaging>jar</packaging>
    <name>AOP Modern</name>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

package at.aydin.lab.aop.modern;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AopModernApplication {
    public static void main(String[] args) {
        SpringApplication.run(AopModernApplication.class, args);
    }
}

package at.aydin.lab.aop.modern;

import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class CalculatorRunner implements CommandLineRunner {
    private final Calculator calculator;
    public CalculatorRunner(Calculator calculator) {
        this.calculator = calculator;
    }

    @Override
    public void run(String ... args) {
        System.out.println("Ergebnis: " + calculator.add(4, 7));
    }
}

package at.aydin.lab.aop.modern;

public interface Calculator {
    int add(int left, int right);
}

package at.aydin.lab.aop.modern;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public
@interface
Tracked {
}

package at.aydin.lab.aop.modern;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

@Aspect
@Component
// Design Pattern: Interceptor / Aspect
// Zweck: Monitoring bleibt getrennt von der Geschäftslogik.
public class TrackingAspect {
    @Around("@annotation(Tracked)")
    public Object measure(ProceedingJoinPoint joinPoint) throws Throwable {
        long started = System.nanoTime();
        try {
            return joinPoint.proceed();
        } finally {
            long micros = (System.nanoTime() - started) / 1_000;
            System.out.printf("%s dauerte %d µs%n", joinPoint.getSignature().toShortString(), micros);
        }
    }
}

package at.aydin.lab.aop.modern;

import org.springframework.stereotype.Service;

@Service
public class TrackedCalculator implements Calculator {
    @Override
    @Tracked
    public int add(int left, int right) {
        return left + right;
    }
}

package at.aydin.lab.aop.modern;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;

class TrackedCalculatorTest {
    @Test
    void addsNumbersWithoutSpringContext() {
        Calculator calculator = new TrackedCalculator();
        assertEquals(11, calculator.add(4, 7));
    }
}