Andrej Koelewijn

Joseph thinks AOP is inobvious and makes it hard for the programmer to understand what is going on. I don’t understand why he says that. The first time I read about AOP I was thinking, this is so obvious, why didn’t i think of that before. Just put related code together, with a specification of where and when it should be executed. So clean, so obvious and so easy to understand.
In Joseph’s security example, I would say that AOP makes it all so much easier to understand for the programmer. AOP is great to achieve simple solutions.

Get it here.

It appears that some people are concerned about portability of the ref cursors I described earlier. I wish this would also trouble me, but the reality is that the project I work on these days uses Oracle and it’s not going to use anything else anytime soon. We are building a java web application on top of Oracle Applications 11i (CRM module). I don’t think Oracle is going to port this to mysql or db2. So for this project I don’t really care about portability.

And the fact is, I want to know all the special features Oracle includes in their
database, as it gives me a better understanding of when to use Oracle or something else, for example PostgreSQL. Some features are really usefull.

At home I use PostgreSQL to try things out. I have a pentium III – 500, and it’s no fun to run Oracle on that. PostgreSQL is a nice replacement. And it supports ref cursors btw. I haven’t tried it, so I don’t know how good the postgresql jdbc drivers support this.

I don’t have any experience with other databases, so I don’t know how well stored procedures and ref cursors are supported on other database. Anybody?

Fred asked whether stored procedures shouldn’t be avoided to get platform/vendor independence. Maybe. But the reality is that databases often live longer than programming languages. Most companies in the netherlands using oracle databases write their applications in Oracle Forms, before that in c and c++. Today they are looking at java, and in the future probably .net. So portability to them means that one database should be able to port to different languages, not that one language should be able to port to multiple databases. I think it improves usability a lot if you put all your business rules as much as possible in the database, by using stored procedures and packages. That way you can easily reuse them when you switch to a different programming language. And in this situation I think stored procedures and ref cursors really do make sense.

Fred writes:

I was under the impression that Oracle signed up with Eclipse.

True, and they have also proposed a standard for IDE plugins. So i think they signed up with Eclipse to try to make Eclipse use this standard. What they want is that all plugins available for Eclipse will also be available for JDeveloper.

Would be nice if the same plugin could be used in every IDE.

Mats writes:

Hm… it seems like you don’t like choice?! ... It is up to the architect to select the tools he/she knowns are stable and good.

I do like choice. I think it’s the best part of my work to make these choices and define a working architecture. But I do think it scares away companies thay are looking for a stable platform. Usually making a choice for a platform takes months, and they don’t want to redo it every year. It also means you have to retrain the developers very often, which is expensive.

I’ve written a small article about the use of oracle ref cursors in java. The article is in dutch and is available here.

Oracle ref cursors allow you to define queries in stored procedures in the database. They can be used in java by executing a call to the stored procedure and then looping through the resultset. The big advantage here is that the oracle developers can provide ready made queries to the java developers, so the java developers do not have to know a lot of sql. I see that a lot of java programmers do not know how to write good sql queries, and lack knowledge about the oracle optimizer and ways to determine query problems (explain plan,etc). Now you can leave this to the oracle developers, and the java developers can do what they are good at, writing java code.

A couple of weeks ago I attended a oracle seminar about JHeadstart. This is a tool created by Oracle Consulting in the Netherlands that allows you to quickly setup a new java application using UIX, BC4J and Oracle’s MVC framework. They are also starting to support JSP and Struts. JHeadstart allows you to generate an application based on data in the Oracle Designer Repository, which may be a good way to migrate your old Oracle Forms application to Java.

An article about this seminar is available here (in Dutch).

Developers often wonder why j2ee certification is important. If it works, it works. But I think there are a lot of companies right now that still have to make a platform choice for future developments. And they want to be able to make this choice for a longer period, and are therefore looking for standards.

For example, many companies that are right now using Oracle Designer and Developer are investigating if they should use a new development platform. It’s not that designer and developer are worse than .net or j2ee, but Oracle has been very unclear about the future of these products. All it’s communication recently has been about java and j2ee, and about the fact that no new development will be done on the old tools.

So companies are starting to look at j2ee and .net. And what do they see when they look at j2ee? Uncertainty. Many different competing, fast moving standards. For example, for the web presentation layer they can use JSP or Oracle’s UIX (user interface xml), velocity, or should they wait untill JSF is available? And for the data layer, should they use DAO, JDO, EJB’s, BC4J, Toplink , or…. How can they make a platform choice for the future if everything keeps moving so fast? If they decide to use the oracle tools, such as uix and bc4j it will be very costly to switch to something else a year from now.

Would you pay a lot of money for an application server and development tools, if you were uncertain if it was the right choice? There’s less risk in choosing a free, certified, open source application server and development tools. When you afterwards decide j2ee is the way to go you can always switch to expensive closed sourced alternatives (would you want to?).

It hasn’t been announced on the jakarta website yet, but the binaries are available here . The release notes list all the changes.

TheServerSide has a matrix of most j2ee application servers, listing all the standards they support. The list is bigger than i thought.

Geoff is talking about ways to communicate within development teams. I really like IM. In my current project we are using sametime. The reason i like it, is that during a meeting (usually phone meetings, as our project is working from different locations) you can communicate with some participants without the others noticing, and agree upon some point before bringing it up in the meeting. Also, it allows you to get some real communication done during boring meetings…

This was the big question in a discussion i had yesterday with an IT manager working for vodafone-live. He gave a presentation about the j2ee intrastructure used for vodafone-live at an IT-eye seminar yesterday. Vodafone-live is a portal for internet phones, and he demoed it on a panasonic gprs phone. This panasonic phone is a small clamshell phone, with a tiny color screen, just big enough to do some basic web browsing. Info about trafic jams, restaurants etc. His vision for the future was something called a PAP, personal access point. PAP phones would be as small as possible, i.e., smaller than the panasonic he demoed, and for people requiring a larger screen, public screens will be available everywhere. All your data and applications would be available through this phone. Sounds like a miniature x-terminal.

My reaction was, why not pda sized? I’ve tried one of those new sony clie’s, with the 320×320 color screen, and that’s a lot better than the tiny phone screen. So i’m waiting for sony to integrate a phone into their newest pda, you know the one with a keyboard, 480×320 screen, 2 megapixel camera. Seems like the perfect combination of usable screen size and portability. I really don’t like the idea of having to find a public screen when i need more screen real estate. Feels like a return to the kermit phones (anybody in the netherlands remember?). This was a mobile phone system, where you had network access only on certain points near an antenna. Big mistake.

And with the power of todays pda’s (400 Mhz) i feel it’s almost time to throw out the notebook. Just take your pda to work, plugin it into a docking-station, connect it to a screen and keyboard, and you don’t need a real pc or laptop anymore.

Another interesting thing mentioned yesterday was that j2me is really doing well on mobile phones. Guess it’s time to try it out. The big hit now is a formula one racing game. Total size 37Kb. About the size of the old commodore 64 games. Maybe we can convert all those to j2me. Any takers for hero and delta?