Developing Laszlo Applications
Once you have installed and started the Laszlo Presentation Server, you will undoubtedly want to begin developing your rich client applications. The good and bad news here is that there is no Laszlo IDE. So, you will likely need to use your existing IDE to develop Laszlo applications. Of course this is nice because it requires no change in your usual routine—any IDE that supports XML will do. The downside is that there are no truly integrated feature—other than checking to make sure your XML is valid. Eclipse users, take note: there is a Laszlo plugin for Eclipse.
The LZX language and syntax is straightforward, however the most difficult part of developing RIAs for J2EE developers is generally adopting the new paradigm. We're so used to having a clean separation of logic and presentation (well, mostly clean) on the server that it takes a while to re-learn what types of logic are best handled in the client user interface. Additionally, we don't need to reload the view every time, we can do things like simply update the data inside of the client, that are much more akin to traditional desktop applications than Web/enterprise ones.
Component Model
Laszlo has an entire component model and includes the usual useful components: list boxes, menus, new windows, and the like. These components are object-oriented in that you can extend them as you wish. You can also apply your own styling to them and even create your own. I should note that they have a good look to them.
Richness
In addition to being able to develop form-based applications and more traditional UIs, Laszlo supports the use of media. Audio, video, and animation can all be added using simple tags and tweaked via scripting. I found this to be amazingly simple. The catch is that any video must be in Flash format—but this allows you to embed Flash animations and stills in SWF format, as well.
Data Interaction
Laszlo allows interaction with data—both on the client-side using data binding techniques, and through the server using XML and remote procedure calls. One big downfall that I see is the lack of database interaction allowed. If you want to call on a database, you will need to create something on the server that will do so. However, the handling of RPC is noteworthy: you can call on Java RPC, XML-RPC or Laszlo native RPC. The XML support is healthy; XML datasets can be easily searched via XPath.
Laszlo's Admin Console
Notable Features
Outside of development and language issues, there are a number of items that should be noted:
- An Admin Console: Quite rudimentary, however it does show key logging and server information (see Figure 1).
- Persistent Connections: This allows you to create applications that require real-time updating, such as instant messaging. It also allows you to maintain a "buddy list."
- Built-in Debugger: By simply adding an attribute to the root tag of your LZX templates, you activate this extremely valuable debugger.
A Solid Development Environment
Overall, Laszlo looks to be a good development environment for developing RIAs. The open source model is promising, as is where they have taken it to date. Laszlo is being used in a number of high-profile sites and seems to be taking a foothold in the J2EE community. While it seems to be lacking in a few areas—most notably integrated database and SQL support—it's usage of XML and JavaScript keep the learning curve short. If you are looking at RIA development, I recommend at least evaluating this software.
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