Ron Bodkin's Blog

Industry Case Studies at AOSD 2006

Rob Harrop of Interface21 presented how Spring users were following the three phases of AOP adoption ranging from exploration and enforcement through infrastructure aspects and on to core domain uses. Rob highlighted some interesting examples of Spring users at each phase, ranging from reporting on enforcing architectural policy to using AOP to keep database views current. It is interesting that Rob uses IntelliJ with @AspectJ syntax: his AspectJ users are all on Java 5 and in general he sees projects that are still on 1.3 or that are on 5, but not many on 1.4. Ali Duck presented interesting findings from interviewing real world projects that were using AOP, mostly with great results.

Uwe Hohenstein of Siemens presented using AOP to automatically update database statistics to keep good query performance and Michael Mortensen of Hewlett Packard presented how they are using AOP with frameworks. InfraRED presented their approach to application performance management with AOP, now also using AspectJ 5 load-time weaving. Dean Wampler gave a nice presentation on lessons from his Contract4J tool that uses AspectJ to support Design by Contract. I also presented a case study on how we've been using AspectJ for monitoring UI and system events to improve the UI and to support macros at DaimlerChrysler with car diagnostic tools.

Alex Vasseur presented on BEA’s prototype of AOP support in the VM, an initiative I hope to see them continue investing in. Andy Clement showed the latest and greatest AspectJ Development Tools for Eclipse. Not only do they keep improving but I actually think AJDT is catching up to JDT, which is no mean feat. Those of us who use AJDT often complain about what’s not there, but it’s really impressive how much IS now working.

Demos at AOSD 2006

There were seventeen demos at AOSD, most of which were quite interesting. I was only sorry I couldn’t attend more of them! I presented the Glassbox Troubleshooter which uses AspectJ for Java application troubleshooting and the Glassbox Inspector data collector and had some good discussions with attendees about how it works and future directions.

I enjoyed seeing AO4BPEL which uses AOP for Business Process Mamanagement, by extending IBM’s BPEL engine BPWS4J to allow aspects to interact with business processes (e.g., adding promotions or performance monitoring across processes) and also to provide middleware aspects (like reliability and security) for SOAP messaging. I also was interested in a talk about Phoenix.NET, a research project for AOP on .NET, along with a discussion of how Microsoft is also concerned about a number of facets of AOP, in many ways relating to losing control. This probably sounds familiar.

Enterprise AOP Tutorial at AOSD

The week started off well as Dean Wampler and I presented a full day tutorial on Enterprise AOP to about 20 attendees. It was a great audience, mostly of experienced developers and architects who wanted to take their AOP and AspectJ knowledge to the next level. We taught the concepts of AOP and how to apply them in the morning. Then in the afternoon, everyone did well on the hands on exercises, which always test you after things sounded so straightforward in the lecture.

This followed a well attended AOP talk I gave at the Software Development West conference the week before. In both cases, I'm seeing more experience and knowledge among developers who come to talks about AOP, as well as interest in pragmatic questions about the next steps in adoption.

AOSD 2006 Conference Overview

I just returned from AOSD 2006 in Bonn, Germany with over 250 people in attendence even with TheServerSide symposium and EclipseCon happening the same week. There was good representation from architects and developers who came to share their experiences and learn more, as well as participation from tool developers and a large contingent of researchers and grad students. It's great to see the caliber of students who are excited about AOP and recent graduates who are using and promoting AOP at their new companies. 

Next year the conference is in Vancouver, and I'm responsible for publicity. I'd love to hear your ideas for how we can reach out to more of those interested in aspects. Some of this year's highlights follow as additional blog entries.

My New AOP@Work Article: Next steps with aspects

I'm pleased to announce the publication of a new article I wrote called "Next Steps with Aspects: After Learning Advice" as part of the AOP@Work article series on IBM Developerworks. The article gives advice for effective applications, integration, and adoption at each of these four stages of using aspects:

• Learning and experimenting. I show examples of exception logging, performance tracing, and enforcement aspects and a technique to reuse library aspects.
• Solving real problems. I discuss how to integrate AOP with tools and managing dependencies,  show how to implement license enforcement and error handling and how to extend library aspects using Glassbox as an example.
• Integrating aspects into core development.  I look at using aspects for fine-grained authorization, keeping persistent relationships in sync, and for monitoring and recording macros in a UI. I also discuss some more advanced techniques such as exposing business relationships.
• Sharing with others. This section looks at how to create reusable aspects effectively, looking at pointcut interfaces and using aspects to allow for feature variations.

I'd welcome your input on the article, and would love to hear how you are using aspects.

Glassbox Troubleshooter & Inspector 1.0 Released

We just announced the 1.0 Release of the Glassbox Troubleshooter product and the Glassbox Inspector project. The Glassbox Troubleshooter builds on the Glassbox Inspector’s AspectJ and JMX monitoring technology. The Troubleshooter adds root cause analysis and a focused GUI client that dramatically simplifies the process of Java troubleshooting. Our goal is to winnow down most of the common performance and reliability problems in enterprise development, providing a concise summary of what is wrong with supporting evidence to make it clear. The product is free to try, and we’d love your feedback! I see the product as especially helpful for finding problems in production and when integration or system testing code. See the screen shot below for an example of the kind of information it provides. You can also learn more at http://www.glassbox.com

Just last week, I had a great experience working with a manged service provider where they were able to download, install, run the product and get valuable information about their application in a QA environment in less than half a day (and half of the time was spent figuring out how to uninstall another monitoring product!).

p.s. Stay tuned for more about designing the next releases.

First the Top Ten Then...

I was pleased to see today that on Eclipse’s downloads page it now lists the top 10 downloads from eclipse.org. And AJDT (the AspectJ plugin for Eclipse) was #10 on the list. That’s great news to see! J  It's another nice validation of the traction AOP is getting.

I’d be interested in knowing what the download rates for AspectJ and AJDT are these days… I think it was 10,000-20,000 per month late last year. Moreover, when I looked recently, the core Spring framework is at at least 50,000 downloads per month these days. And as Adrian, Alex, Jonas and others have blogged Spring 2.0 promises to be a big step forward in the maturity of aspects, making incremental adoption easier than ever. Of course JBoss 4 is building their EJB 3 container on AOP too.

I had a great time last fall speaking at places like Software Development West, OOPSLA, and the Colorado Software Summit. At the Colorado Software Summit, Roberto Chinnici of Sun talked about including proxy-based AOP as a promising future for the J2EE specification, which would be great validation.

I think this year we are going to see more developers using AOP as an effective tool to get work done, and they are going to find it easier to pick up prebuilt tools that can be extended with AOP. For example, our Glassbox Inspector open source project lets you monitor performance and failures in Java applications. And if you want to monitor something new, you can write an aspect in a few lines of code (or XML) and extend the framework. You can even package this as a jar and just deploy it with the Glassbox Inspector and with load-time weaving it just works. And I believe this is going to be the year where we will see more and more interesting aspect libraries and interesting ways that plain old open source projects start capitalizing on aspects for extensibility (e.g., publishing pointcuts instead of old-school callback hooks, or adding in optional features through aspects).

p.s. I'm also glad that Jonas is moving to the Bay Area this month. Maybe we can do some hacking together and integrate some of the optimizations I've made to load-time weaving into AspectJ's CVS HEAD. In the meanwhile, stay tuned for an experimental release if you'd like to test out a much lower memory version of load-time weaving ...

A Hidden Treasure: Weaving with References to Missing Third Party Libraries, and Weaving on Installation

One of the nice little features of AspectJ 5 that isn't documented (at least no where that I can find) is the valuable new Xlint warning cantFindType;  This solves a major problem AspectJ users have faced until now when working with third party libraries. Previously when weaving into a jar file, you would to have to track down all the dependent jars  of that library and put them on the classpath so AspectJ could resolve all the types. This could be quite difficult when weaving into libraries like Spring or Hibernate, where there are many adapter classes that support a large variety of, e.g., cache managers.  It's also a problem in load-time weaving. In that context, a smaller example I ran into was when weaving into the Struts jar, where Action that has a type reference to a legacy data source that is not normally shipped with Struts. The Java code will not even invoke the method that refers to that data source, but by default AspectJ tries to weave everything at once and when it fails to resolve it, it will error out.

However, now you can fix the problem, telling AspectJ to simply ignore (or warn you) for missing types.  Simply create an Xlint.properties file and either copy one (like this one from the Glassbox Inspector project) or create a blank one. You can then add or edit two entries:

cantFindType = ignore

cantFindTypeAffectingJPMatch = warning

You can then use the Xlint properties file to weave with AJDT in Eclipse, with an ant task, with maven or the ajc compiler (or even a smaller command-line weaving utility I talk about below). You can also use it by adding a reference to it in the META-INF/aop.xml file for load-time weaving.

Put together, this allows you to weave and run with incomplete dependencies. I was reminded of how nice this feature was tonight when I ran into a problem weaving into a project jar because there is another configuration of the code that uses a 3rd party jar. On this project, we are doing a command line weave on installation for a GUI application, to allow us to minimize the time for weaving and to minimize change sizes. whereby an aspect was choking on a jar that had a reference to an unused 3rd party library in one, even with smaller configurations of your own application. So we don't want to include all these optional libraries in our distribution! Instead, I was able to just create an Xlint.properties file and fix the problem. By the way, I also created a tiny 20k contribution to support command-line weaving with just the aspectjweaver.jar instead of pulling along a few megabytes of additional AspectJ compiler code. If you want to use that please let me know and I can upload a few small updates I had to make and even a jar. Hopefully we'll get this integrated into AspectJ 1.5.1

It is worth noting that if you do this, you should make sure you won't be running the woven jar in an environment where the missing dependency is present... I think this is so useful that it is probably worth making the case of missing types a warning rather than an error. I also think it's a little surprising that it is an Xlint property. But I'm sure glad the feature is available!

before() : christmas() { release(); }

This morning some great news arrived in my in box. AspectJ 5 final shipped today. It's been over a year in the making and I'm really excited we've hit this milestone.

I for one want to say thank you to the AspectJ committers for working so long and hard to release AspectJ 5! Adding generics support to AspectJ was certainly a major undertaking and it’s great that the end result has been so stable and, in fact, greatly improved even for older Java VM’s. This is a real milestone in the history of aspect-oriented programming and a great Christmas present for all of us.

If you are using AspectJ, I'd encourage you to download it and the Eclipse tools . If you aren't yet using AspectJ, this is a great time to try it and see for yourself what aspects can do!

Load-Time Weaving for WebSphere Available

Ramnivas and I are working on an interesting project applying AspectJ to do fine-grained security in a WebSphere 6.0 environment. We wanted to use load-time weaving to let us build modules separately in the RAD IDE and then weave our aspects at load-time. We also wanted to mock the EJB container behavior for integration tests. However, WebSphere 6.0 uses IBM's Java 1.4 VM that doesn't support any Java agents for weaving.

However, I was able to track down the details of the WebSphere ClassLoader Plug In API (the hard part) and write a simple Plug In that lets you do load-time weaving with AspectJ 5 for application classes in WebSphere using its embedded Java 1.4 VM. For older WebSphere implementations, this should also work on their Java 1.3 VM's. You can download the jar and also read about how to use it in more detail at the AspectJ bugzilla report in which I contributed it (see https://bugs.eclipse.org/bugs/show_bug.cgi?id=111027).