Advising Transactional Operations

가령 transactional operation과 몇 가지 기본적인 profiling advice를 둘 다 실행하고 싶다고 가정해 보겠습니다. <tx:annotation-driven/>의 context에서 이것을 어떻게 구현할 수 있을까요?

updateFoo(Foo) 메서드를 호출할 때, 다음과 같은 action이 발생하기를 원합니다:

• 설정된 profiling aspect가 시작됩니다.
• transactional advice가 실행됩니다.
• advised 객체의 메서드가 실행됩니다.
• transaction이 commit됩니다.
• profiling aspect가 전체 transactional 메서드 호출의 정확한 duration을 report합니다.

이 chapter는 (transaction에 적용되는 부분을 제외하고는) AOP를 자세히 설명하는 데 관심이 없습니다. AOP 설정과 일반적인 AOP에 대한 자세한 내용은 AOP를 참조하세요.

다음 코드는 앞에서 설명한 simple profiling aspect를 보여 줍니다:

1package x.y;
2
3import org.aspectj.lang.ProceedingJoinPoint;
4import org.springframework.util.StopWatch;
5import org.springframework.core.Ordered;
6
7public class SimpleProfiler implements Ordered {
8
9	private int order;
10
11	// allows us to control the ordering of advice
12	public int getOrder() {
13		return this.order;
14	}
15
16	public void setOrder(int order) {
17		this.order = order;
18	}
19
20	// this method is the around advice
21	public Object profile(ProceedingJoinPoint call) throws Throwable {
22		Object returnValue;
23		StopWatch clock = new StopWatch(getClass().getName());
24		try {
25			clock.start(call.toShortString());
26			returnValue = call.proceed();
27		} finally {
28			clock.stop();
29			System.out.println(clock.prettyPrint());
30		}
31		return returnValue;
32	}
33}

1package x.y
2
3import org.aspectj.lang.ProceedingJoinPoint
4import org.springframework.util.StopWatch
5import org.springframework.core.Ordered
6
7class SimpleProfiler : Ordered {
8
9	private var order: Int = 0
10
11	// allows us to control the ordering of advice
12	override fun getOrder(): Int {
13		return this.order
14	}
15
16	fun setOrder(order: Int) {
17		this.order = order
18	}
19
20	// this method is the around advice
21	fun profile(call: ProceedingJoinPoint): Any {
22		var returnValue: Any
23		val clock = StopWatch(javaClass.name)
24		try {
25			clock.start(call.toShortString())
26			returnValue = call.proceed()
27		} finally {
28			clock.stop()
29			println(clock.prettyPrint())
30		}
31		return returnValue
32	}
33}

advice의 ordering은 Ordered 인터페이스를 통해 제어됩니다. advice ordering에 대한 전체 내용은 Advice ordering을 참조하세요.

다음 설정은 profiling과 transactional aspect가 원하는 순서로 적용된 fooService 빈을 생성합니다:

1<?xml version="1.0" encoding="UTF-8"?>
2<beans xmlns="http://www.springframework.org/schema/beans"
3	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4	xmlns:aop="http://www.springframework.org/schema/aop"
5	xmlns:tx="http://www.springframework.org/schema/tx"
6	xsi:schemaLocation="
7		http://www.springframework.org/schema/beans
8		https://www.springframework.org/schema/beans/spring-beans.xsd
9		http://www.springframework.org/schema/tx
10		https://www.springframework.org/schema/tx/spring-tx.xsd
11		http://www.springframework.org/schema/aop
12		https://www.springframework.org/schema/aop/spring-aop.xsd">
13
14	<bean id="fooService" class="x.y.service.DefaultFooService"/>
15
16	<!-- this is the aspect -->
17	<bean id="profiler" class="x.y.SimpleProfiler">
18		<!-- run before the transactional advice (hence the lower order number) -->
19		<property name="order" value="1"/>
20	</bean>
21
22	<tx:annotation-driven transaction-manager="txManager" order="200"/>
23
24	<aop:config>
25		<!-- this advice runs around the transactional advice -->
26		<aop:aspect id="profilingAspect" ref="profiler">
27			<aop:pointcut id="serviceMethodWithReturnValue"
28					expression="execution(!void x.y..*Service.*(..))"/>
29			<aop:around method="profile" pointcut-ref="serviceMethodWithReturnValue"/>
30		</aop:aspect>
31	</aop:config>
32
33	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
34		<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
35		<property name="url" value="jdbc:oracle:thin:@rj-t42:1521:elvis"/>
36		<property name="username" value="scott"/>
37		<property name="password" value="tiger"/>
38	</bean>
39
40	<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
41		<property name="dataSource" ref="dataSource"/>
42	</bean>
43
44</beans>

유사한 방식으로 원하는 만큼의 추가 aspect를 설정할 수 있습니다.

다음 example은 앞의 두 example과 동일한 setup을 생성하지만 순수하게 XML 선언적 approach를 사용합니다:

1<?xml version="1.0" encoding="UTF-8"?>
2<beans xmlns="http://www.springframework.org/schema/beans"
3	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4	xmlns:aop="http://www.springframework.org/schema/aop"
5	xmlns:tx="http://www.springframework.org/schema/tx"
6	xsi:schemaLocation="
7		http://www.springframework.org/schema/beans
8		https://www.springframework.org/schema/beans/spring-beans.xsd
9		http://www.springframework.org/schema/tx
10		https://www.springframework.org/schema/tx/spring-tx.xsd
11		http://www.springframework.org/schema/aop
12		https://www.springframework.org/schema/aop/spring-aop.xsd">
13
14	<bean id="fooService" class="x.y.service.DefaultFooService"/>
15
16	<!-- the profiling advice -->
17	<bean id="profiler" class="x.y.SimpleProfiler">
18		<!-- run before the transactional advice (hence the lower order number) -->
19		<property name="order" value="1"/>
20	</bean>
21
22	<aop:config>
23		<aop:pointcut id="entryPointMethod" expression="execution(* x.y..*Service.*(..))"/>
24		<!-- runs after the profiling advice (cf. the order attribute) -->
25
26		<aop:advisor advice-ref="txAdvice" pointcut-ref="entryPointMethod" order="2"/>
27		<!-- order value is higher than the profiling aspect -->
28
29		<aop:aspect id="profilingAspect" ref="profiler">
30			<aop:pointcut id="serviceMethodWithReturnValue"
31					expression="execution(!void x.y..*Service.*(..))"/>
32			<aop:around method="profile" pointcut-ref="serviceMethodWithReturnValue"/>
33		</aop:aspect>
34
35	</aop:config>
36
37	<tx:advice id="txAdvice" transaction-manager="txManager">
38		<tx:attributes>
39			<tx:method name="get*" read-only="true"/>
40			<tx:method name="*"/>
41		</tx:attributes>
42	</tx:advice>
43
44	<!-- other <bean/> definitions such as a DataSource and a TransactionManager here -->
45
46</beans>

앞선 설정의 결과는 profiling과 transactional aspect가 그 순서로 적용된 fooService 빈입니다. profiling advice가 들어가는 시점에는 transactional advice 다음에, 나오는 시점에는 transactional advice 전에 실행되도록 하려면, profiling aspect 빈의 order 프로퍼티 값을 transactional advice의 order 값보다 더 높게 바꾸면 됩니다.

추가 aspect는 유사한 방식으로 설정할 수 있습니다.