DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports Events Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones AWS Cloud
by AWS Developer Relations
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones
AWS Cloud
by AWS Developer Relations
Building Scalable Real-Time Apps with AstraDB and Vaadin
Register Now

Trending

  • Security Challenges for Microservice Applications in Multi-Cloud Environments
  • Exploratory Testing Tutorial: A Comprehensive Guide With Examples and Best Practices
  • Auto-Scaling Kinesis Data Streams Applications on Kubernetes
  • What Is React? A Complete Guide

Trending

  • Security Challenges for Microservice Applications in Multi-Cloud Environments
  • Exploratory Testing Tutorial: A Comprehensive Guide With Examples and Best Practices
  • Auto-Scaling Kinesis Data Streams Applications on Kubernetes
  • What Is React? A Complete Guide
  1. DZone
  2. Coding
  3. Java
  4. Java: Exception Translation with AspectJ

Java: Exception Translation with AspectJ

Michael Scharhag user avatar by
Michael Scharhag
·
Feb. 04, 14 · Interview
Like (2)
Save
Tweet
Share
15.97K Views

Join the DZone community and get the full member experience.

Join For Free

Within this blog post I describe how you can use AspectJ to automatically translate one type of exception to another. 

The problem
Sometimes we are in situations where we have to convert an exception (often thrown by a third-party library) to another type of exception. Assume you are using a persistence framework like hibernate and you do not want to leak hibernate specific exceptions out of a certain application layer. Maybe you are using more than one persistence technology and you want to wrap technology specific exceptions into a common base exception. In such situations, one can end with code like this:

public class MyRepository {
 	public Object getSomeData() { 
 		try {
 			// assume hibernate is used to access some data
 		} catch(HibernateException e) {
 			// wrap hibernate specific exception into a general DataAccessException
 			throw new DataAccessException(e);
 		}
 	}
}

Of course this becomes ugly if you have to do this every time you access a certain framework.
The AspectJ way
AspectJ is an aspect oriented programming (AOP) extension for Java. With AspectJ we can define Cross-cutting concerns that take care of the exception translation process for us.

To get started we first have to add the AspectJ dependency to our project:

<dependency>
 	<groupId>org.aspectj</groupId>
 	<artifactId>aspectjrt</artifactId>
 	<version>1.7.4</version>
</dependency>

Next we have to set up ajc, the compiler and bytecode weaver for AspectJ. This step depends on the developing environment you are using, so I will not go into details here. Eclipse users should have a look at theAspectJ Development Tools (AJDT) for Eclipse. IntelliJ IDEA users should make sure the AspectJ plugin is enabled. There is also an AspectJ Maven plugin available (check this pom.xml for an example configuration).

Now let's define our aspect using AspectJ annotations:

@Aspect
public class ExceptionTranslationAspect {

 	@Around("execution(* com.mscharhag.exceptiontranslation.repository..*(..))")
 	public Object translateToDataAccessException(ProceedingJoinPoint pjp) throws Throwable {
 		try {
 			return pjp.proceed();
 		} catch (HibernateException e) {
 			throw new DataAccessException(e);
 		}
 	}
}

Using the @Aspect annotation we can declare a new aspect. Within this aspect we use the @Aroundannotation to define an advice that is always executed if the passed pointcut is matched. Here, the pointcut

execution(* com.mscharhag.exceptiontranslation.repository..*(..))

tells AspectJ to call translateToDataAccessException() every time a method of a class inside thecom.mscharhag.exceptiontranslation.repository package is executed.
Within translateToDataAccessException() we can use the passed ProceedingJoinPoint object to proceed the method execution we intercepted. In this example we just add a try/catch block around the method execution. Using the ProceedingJoinPoint instance we could also do more interesting things like analyzing the method signature using pjp.getSignature() or accessing method parameters withpjp.getArgs().

We can now remove the try/catch block from the example repository implementation shown above and use a simple test to verify our aspect is working:

public class MyRepositoryTest {

 	private MyRepository repository = new MyRepository();

 	@Test(expected = DataAccessException.class)
 	public void testExceptionTranslation() {
 		this.repository.getSomeData();
 	}
}


Conclusion
Using AspectJ we can easily automate the conversion of Java runtime exceptions. This simplifies our code by removing try/catch blocks that would otherwise be required for exception translation.

You can find the full source of the example project on GitHub.

AspectJ Java (programming language) Translation intellij

Published at DZone with permission of Michael Scharhag, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Trending

  • Security Challenges for Microservice Applications in Multi-Cloud Environments
  • Exploratory Testing Tutorial: A Comprehensive Guide With Examples and Best Practices
  • Auto-Scaling Kinesis Data Streams Applications on Kubernetes
  • What Is React? A Complete Guide

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com

Let's be friends: