포인트컷, 어드바이스, 어드바이저

- 포인트컷( Pointcut ): 어디에 부가 기능을 적용할지, 어디에 부가 기능을 적용하지 않을지 판단하는 필터링 로직이다. 주로 클래스와 메서드 이름으로 필터링 한다. 이름 그대로 어떤 포인트(Point)에 기능을 적용할지 하지 않을지 잘라서(cut) 구분하는 것이다.

- 어드바이스( Advice ): 이전에 본 것 처럼 프록시가 호출하는 부가 기능이다. 단순하게 프록시 로직이라 생각하면 된다.

- 어드바이저( Advisor ): 단순하게 하나의 포인트컷과 하나의 어드바이스를 가지고 있는 것이다. 쉽게 이야기해서 포인트컷1 + 어드바이스1이다.

 

public interface ServiceInterface {
    void save();

    void find();
}

@Slf4j
public class ServiceImpl implements ServiceInterface {
    @Override
    public void save() {
        log.info("save 호출");
    }

    @Override
    public void find() {
        log.info("find 호출");
    }
}

@Slf4j
public class TimeAdvice implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        log.info("TimeProxy 실행");
        long startTime = System.currentTimeMillis();

        Object result = invocation.proceed();

        long endTime = System.currentTimeMillis();
        long resultTime = endTime - startTime;
        log.info("TimeProxy 종료 resultTime={}", resultTime);
        return result;
    }
}

 

 

어드바이저

@Test
void advisorTest1() {
    ServiceInterface target = new ServiceImpl();
    ProxyFactory proxyFactory = new ProxyFactory(target);
    DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(Pointcut.TRUE, new TimeAdvice());
    proxyFactory.addAdvisor(advisor);
    ServiceInterface proxy = (ServiceInterface) proxyFactory.getProxy();

    proxy.save();
    proxy.find();
}

 

 

포인트컷

@Test
@DisplayName("직접 만든 포인트 컷")
void advisorTest2() {
    ServiceInterface target = new ServiceImpl();
    ProxyFactory proxyFactory = new ProxyFactory(target);
    DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(new MyPointCut(), new TimeAdvice());
    proxyFactory.addAdvisor(advisor);
    ServiceInterface proxy = (ServiceInterface) proxyFactory.getProxy();

    proxy.save();
    proxy.find();
}

@Test
@DisplayName("스프링이 제공하는 포인트컷")
void advisorTest3() {
    ServiceInterface target = new ServiceImpl();
    ProxyFactory proxyFactory = new ProxyFactory(target);
    NameMatchMethodPointcut pointcut = new NameMatchMethodPointcut();
    pointcut.setMappedName("save");
    DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(pointcut, new TimeAdvice());
    proxyFactory.addAdvisor(advisor);
    ServiceInterface proxy = (ServiceInterface) proxyFactory.getProxy();

    proxy.save();
    proxy.find();
}

static class MyPointCut implements Pointcut {

    @Override
    public ClassFilter getClassFilter() {
        return ClassFilter.TRUE;
    }

    @Override
    public MethodMatcher getMethodMatcher() {
        return new MyMethodMatcher();
    }
}

static class MyMethodMatcher implements MethodMatcher {

    private String matchName = "save";

    @Override
    public boolean matches(Method method, Class<?> targetClass) {
        boolean result = method.getName().equals(matchName);
        log.info("포인트컷 호출 method={} targetClass={}", method.getName(), method.getClass());
        return result;
    }

    @Override
    public boolean isRuntime() {
        return false;
    }

    @Override
    public boolean matches(Method method, Class<?> targetClass, Object... args) {
        return false;
    }
}

- 예제로 만든 것이지 실무에서 직접 만들 일은 없다.

 

 

여러 어드바이저 함께 적용

@Slf4j
public class MultiAdvisorTest {

    @Test
    @DisplayName("여러 프록시")
    void multiAdvisorTest1() {
        //client -> proxy2(advisor2) -> proxy1(advisor1) -> target

        //프록시1 생성
        ServiceInterface target = new ServiceImpl();
        ProxyFactory proxyFactory1 = new ProxyFactory(target);
        DefaultPointcutAdvisor advisor1 = new DefaultPointcutAdvisor(Pointcut.TRUE, new Advise1());
        proxyFactory1.addAdvisor(advisor1);
        ServiceInterface proxy1 = (ServiceInterface) proxyFactory1.getProxy();

        //프록시2 생성, target -> proxy1 입력
        ProxyFactory proxyFactory2 = new ProxyFactory(proxy1);
        DefaultPointcutAdvisor advisor2 = new DefaultPointcutAdvisor(Pointcut.TRUE, new Advise2());
        proxyFactory2.addAdvisor(advisor2);
        ServiceInterface proxy2 = (ServiceInterface) proxyFactory2.getProxy();

        //실행
        proxy2.save();
    }

    @Test
    @DisplayName("하나의 프록시, 여러 어드바이저")
    void multiAdvisorTest2() {
        //client -> proxy -> advisor2 -> advisor1 -> target

        DefaultPointcutAdvisor advisor1 = new DefaultPointcutAdvisor(Pointcut.TRUE, new Advise1());
        DefaultPointcutAdvisor advisor2 = new DefaultPointcutAdvisor(Pointcut.TRUE, new Advise2());

        //프록시1 생성
        ServiceInterface target = new ServiceImpl();
        ProxyFactory proxyFactory = new ProxyFactory(target);

        proxyFactory.addAdvisor(advisor2);
        proxyFactory.addAdvisor(advisor1);
        ServiceInterface proxy = (ServiceInterface) proxyFactory.getProxy();

        //실행
        proxy.save();
    }

    static class Advise1 implements MethodInterceptor {

        @Override
        public Object invoke(MethodInvocation invocation) throws Throwable {
            log.info("advise1 호출");
            return invocation.proceed();
        }
    }

    static class Advise2 implements MethodInterceptor {

        @Override
        public Object invoke(MethodInvocation invocation) throws Throwable {
            log.info("advise2 호출");
            return invocation.proceed();
        }
    }
}

 

※ 하나의 'target'에 여러 AOP가 동시에 적용되어도, 스프링 AOP는 'target'마다 하나의 프록시만 생성한다!!!