Red Hat Summit Red Hat Summit지원콘솔개발자평가판 시작연락처

이 콘텐츠는 선택한 언어로 제공되지 않습니다.

12.3. Applying Aspects in JBoss AOP

To apply an aspect, you define when to execute the aspect code. Those points in execution are called pointcuts. An analogy to a pointcut is a regular expression. Where a regular expression matches strings, a pointcut expression matches events or points within your application. For example, a valid pointcut definition would be, "for all calls to the JDBC method executeQuery(), call the aspect that verifies SQL syntax."
An entry point could be a field access, or a method or constructor call. An event could be an exception being thrown. Some AOP implementations use languages akin to queries to specify pointcuts. Others use tags. JBoss AOP uses both.
The following listing demonstrates defining a pointcut for the Metrics example in JBoss AOP: 
<interceptor name="SimpleInterceptor" class="com.mc.Metrics"/>                  
<bind pointcut="execution (public void com.mc.BankAccountDAO->withdraw(double amount))" >                                                                       
    <interceptor-ref name="SimpleInterceptor" />
</bind>                                                                         
<bind pointcut="execution (* com.mc.billing.->(..))">                           
    <interceptor-ref name="com.mc.Metrics" />
</bind>
Copy to Clipboard Toggle word wrap

1

Defines the mapping of the interceptor name to the interceptor class.

2

Lines 2-4 define a pointcut that applies the metrics aspect to the specific method BankAccountDAO.withdraw().

3

Lines 5-7 define a general pointcut that applies the metrics aspect to all methods in all classes in the com.mc.billing package. There is also an optional annotation mapping if you prefer to avoid XML.
For more information, see the JBoss AOP reference documentation.
JBoss AOP has a rich set of pointcut expressions that you can use to define various points or events in your Java application. Once your points are defined, you can apply aspects to them. You can attach your aspects to a specific Java class in your application or you can use more complex compositional pointcuts to specify a wide range of classes within one expression.
With AOP, as this example shows, you can combine all crosscutting behavior into one object and apply it easily and simply, without complicating your code with features unrelated to business logic. Instead, common crosscutting concerns can be maintained and extended in one place.
Note that code within the BankAccountDAO class does not detect that it is being profiled. Profiling is part of what aspect-oriented programmers deem orthogonal concerns. In the object-oriented programming code snippet at the beginning of this chapter, profiling was part of the application code. AOP allows you to remove that code. A modern promise of middleware is transparency, and AOP clearly delivers.
Orthogonal behavior can also be included after development. In object-oriented code, monitoring and profiling must be added at development time. With AOP, a developer or an administrator can easily add monitoring and metrics as needed without touching the code. This is a very subtle but significant part of AOP, as this separation allows aspects to be layered on top of or below the code that they cut across. A layered design allows features to be added or removed at will. For instance, perhaps you snap on metrics only when you are doing some benchmarks, but remove it for production. With AOP, this can be done without editing, recompiling, or repackaging the code.
맨 위로 이동
Red Hat logoGithubredditYoutubeTwitter

자세한 정보

평가판, 구매 및 판매

커뮤니티

Red Hat 문서 정보

Red Hat을 사용하는 고객은 신뢰할 수 있는 콘텐츠가 포함된 제품과 서비스를 통해 혁신하고 목표를 달성할 수 있습니다. 최신 업데이트를 확인하세요.

보다 포괄적 수용을 위한 오픈 소스 용어 교체

Red Hat은 코드, 문서, 웹 속성에서 문제가 있는 언어를 교체하기 위해 최선을 다하고 있습니다. 자세한 내용은 다음을 참조하세요.Red Hat 블로그.

Red Hat 소개

Red Hat은 기업이 핵심 데이터 센터에서 네트워크 에지에 이르기까지 플랫폼과 환경 전반에서 더 쉽게 작업할 수 있도록 강화된 솔루션을 제공합니다.

Theme

© 2025 Red Hat