Venkat Spring AOP

7/30/2019 Venkat Spring AOP

1/14

SPRING AOP

Venkat Krishnan


2/14

AOP CONCEPT

Aspect-Oriented Programming(AOP)

complements OOP by providing another way ofthinking about program structure.

While OO decomposes applications into a

20/11/2012Venkat Krishnan

,into aspects or concerns.

This enables modularization of concerns such as

transaction management that would otherwise

cut across multiple objects. (Such concerns areoften termed crosscuttingconcerns.)


3/14

AOP CONCEPT


Aspects modularize crosscutting concerns, applying logic that

spans multiple application objects.


4/14

SPRING AOP FRAMEWORK

One of the key components of Spring is the

AOP framework. AOP complements Spring IoC to provide a

very capable middleware solution.


To provide declarative enterprise services,

especially as a replacement for EJB declarativeservices. The most important such service isdeclarative transaction management, whichbuilds on Spring's transaction abstraction.


5/14

SPRING AOP FRAMEWORK

To allow users to implement custom aspects,

complementing their use of OOP with AOP.

Thus you can view Spring AOP as either an


provide declarative transaction

management without EJB; or use the full

power of the Spring AOP framework toimplement custom aspects.


6/14

AOP TERMINOLOGY

Aspect:

A modularization of a concern for which the

implementation might otherwise cut across

multi le ob ects.


Transaction management is a good example of a

crosscutting concern in J2EE applications.

Aspects are implemented using Spring as

Advisors or interceptors.


7/14

AOP TERMINOLOGY

Joinpoint:

Point during the execution of a program, such asa method invocation or a particular exceptionbeing thrown.

In S rin AOP a oin oint is method invocation.


Spring does not use the term joinpointprominently; joinpoint information is accessiblethrough methods on the MethodInvocationargument passed to interceptors, and is

evaluated by implementations of theorg.springframework.aop.Pointcut interface.


8/14

AOP TERMINOLOGY

Advice:

Action taken by the AOP framework at a

particular joinpoint.

Different t es of advice include "around "


"before" and "throws" advice.

Spring models an advice as an interceptor,

maintaining a chain of interceptors "around" the

joinpoint.


9/14

AOP TERMINOLOGY

Pointcut:

A set of joinpoints specifying when an advice

should fire.


specify pointcuts: for example, using regular

expressions.


10/14

AOP TERMINOLOGY

Target object:

Object containing the joinpoint.

Also referred to as advised or proxied object.


proxy:Object created by the AOP framework, including

advice.

In Spring, an AOP proxy will be a JDK dynamicproxy or a CGLIB proxy.


11/14

SPRING AOP


Spring aspects are implemented as proxies that wrap the target object.

The proxy handles method calls, performs additional aspect logic, and

then invokes the target method.


12/14

SPRING ADVICES

Different advice types include:

Around advice:org.aopalliance.intercept.MethodInterceptor


org.springframework.aop.MethodBeforeAdvice

After throwing advice:org.springframework.aop.ThrowsAdvice

After returning advice:org.springframework.aop.AfterReturningAdvice


13/14

CONCEPT

Spring provides classes to represent

pointcuts and different advice types.

Spring uses the term advisorfor an object


represen ng an aspec , nc u ng o anadvice and a pointcut targeting it to specific

joinpoints.


14/14


Venkat Spring AOP

Documents

Transcript of Venkat Spring AOP