DataPower News

I've long been a fan of XML Appliances. Looks like IBM customers like the appliance idea as well. IBM said that DataPower was one of the top-selling products and also announced that DataPower-lution is one of their strategic directions for 2009. Basically, more and more edge functions will be moving into the appliance. And why not use the same device for XML acceleration, load balancing, crypto acceleration, caching, perhaps even WebSEAL replacement (it's just a fancy reverse proxy after all). We'll see how this vision plays out.

In a related news, there is finally a DataPower book and it's 960 pages long. And this is before IBM started adding all these edge functions to the device :).

It Takes a Mental Shift to Benefit from XML Appliances

This article on techtarget is a great illustration of my point from the previous post about the importance of the proper design patterns and techniques required to be able to benefit from XML appliance capabilities.

When implementing Web services Java developers tend to think in terms of Java classes that XML documents map to. Using XSLT (or even Schema) for implementing part of their processing logic is not on their list because the common thinking is that it is too expensive to do it in Java.

With XML appliances the situation is exactly the opposite. XSLT all of a sudden becomes one of the best performing part of an application (although, I would imagine that using Java hardware acceleration such as the one provided by Azul might once again change that). This could be a serious "paradigm shift" for many developers and architects.

Another obstacle to more effective usage of appliances could simply be the lack of XSLT skills. XSLT is essentially a functional language and so it comes with a learning curve attached, especially for complex transformations. It is important to have a good knowledge of XSLT to understand what kind of work can be "outsourced" to an appliance. Not that many developers have this knowledge today, but perhaps it will change with more widespread use of XML appliances.

Improve Your Application Performance with XML Appliance

XML appliances are capable of extremely fast XML parsing and transformation (sometimes the term "wire-speed" is used). The speed is achieved by using hardware acceleration, specially written XML parsers and XSLT engines (you won’t find Xerces on these devices) and optimized operating system (usually, a trimmed-down version of Linux or BSD).

How fast are XML appliances? I’m not aware of published benchmarks; however, I did have a chance to conduct an informal performance testing of DataPower XI50 for a client and the results were quite impressive; for example we saw little to no overhead validating medium-size XML schemas.

Clearly, offloading as much XML processing as possible to an appliance could be a performance booster. So what kind of processing could be done on the device? Here are my recommendations based on the capabilities of the DataPower appliance; the situation could be slightly different with devices from other vendors. (more...)

XML Appliances Begin Supporting Java

Layer7 announced that its appliances will support Java-based custom assertions. Details are sketchy at this point but apparently Layer7 will provide a proprietary SDK for developing assertions. This could be much more powerful mechanism than XSLT-only facilities in IBM DataPower.

So how long before appliances begin supporting JBI and SCA components? The trick here of course is to make sure that an appliance is still a robust low-maintenance device that can't be brought down by a rogue application thread. But if Layer7 was able to figure it out for Java in general (I wonder if they use a general Sun JDK or some kind of a special JDK build), there is no reason why an appliance can't start supporting more advanced specifications such as JBI/SCA.