EAI Blog

Good day, all!

I have completed reading chapters 6 and 7 of the textbook.

The chapters give a good idea of

-what types of middleware are available on the market;

-what the main, defining characteristics of those types of middleware are;

-what advantages, disadvantages and main applications each type of middleware has.

However, the book does not seem to give a good feel of how some complex types of middleware work. It also does not provide clear, visual, easy-to-understand examples on the topic.

As a result, the author succeeds in two cases:

1) when the described technology is relatively simple (RPC, Messaging)

2) when the reader has at least some basic understanding of the subject (in my case it was the understanding of application servers, transaction monitors, and database-oriented middleware).

It seems to me that the author is not so successful in describing complex types of middleware to readers, who do not have any prior knowledge of the subject.

For example, CORBA and COM+ concepts have always been difficult to understand for me, even though I had some limited experience in working with COM+. After reading the chapter I still have a relatively vague idea of the mechanisms that enable CORBA and COM+ to perform their functions.

As of XML Exercise, I was impressed by how easy and developer-friendly the Visual Studio makes performing basic operations with XML.  

Mike

I have completed reading chapter 11 of the textbook.

I liked the way the author clearly described the power and limitations of both XML and XSLT.

I already have some job-related experience working with XML and SOAP. However, the author helped me to see the "big picture" and to better understand the role XML and XSLT play in intracompany and intercompany (B2B) integration.

It was also very interesting to read the detailed description of what happens behind the scene during XSLT transformation. I used to consider XSLT as a "black box" that works in mysterious ways and is capable of transforming XML document into a different XML document or into a document of a different format (HTML, PDF, etc.). Now I have a much better understanding of how XSLT really works including the concepts of "input tree" and "output tree".

Talking about the opportunities for improvement I would like to mention various examples of XML and XSLT files listed in the chapter. Those examples are not accompanied by clear and detailed explanation. It makes it very difficult for person whose knowledge of XML and XSLT is limited to understand the examples.

I was able to understand XML examples because I had prior experience working with XML. However, it was difficult to understand XSLT example without using additional literature.

I have completed reading the second chapter of the textbook.

The nice feature of the book is "By Example" sections that contain practical illustrations for the introduced theoretical concepts.

It was interesting to read about leveraging the user interface as point of information integration (so-called "screen scraping"). At my work I used to support a legacy screen-scraping application that utilized middleware to import information from the mainframe screens into MS Word documents. Therefore I could relate to the author's words regarding controller and server bouncing being the common problems for the screen-scraping applications. The other problem was that every time the appearance of the mainframe screens had been changed, the screen-scraping utility stopped working properly because they relied on certain fields being located at certain position on the screen.

Unfortunately, the author does not give any example of the practical application of the Information Integration Approach described in the book (Identify the data, catalog the data, build the enterprise data model) in chapter 2. It would be interesting to see how that approach can be used in real life. From my understanding, it would be very hard if not impossible to create a decent enterprise data model for a large company with complex structure.