Swing for Web?

winzenghua

java Open Source AJAX-based Web frameworks. Evaluation ResultsWe specified the requirements  for the Open Source Java Web frameworks used in presentation layer of Enterprise  Web Applications:

1. Performance.  
2. Modal dialogs.  
3. Partial page refresh.  
4. Component-based and event-driven.  
The philosophy should be: a Web application should behave like a desktop  application, and it should be developed like a desktop application.  
Is it possible to satisfy all those requirements? How much will we have to  pay for the convenience and flexibility - with performance loss (which  translates into higher hardware cost)?  
For example, explicit  representation of the complex UI state on the server should affect performance  and scalability. Partial page refresh means busy traffic between the client  and server, which also should affect performance.  
To answer those questions, we performed evaluation and performance tests of  the existing Web frameworks.
To meet our performance and usability requirements, a Web framework has to be  AJAX-based, e.g. all components have to use AJAX for partial page  refresh. Most Web frameworks are AJAX-enabled, e.g. only part of the  framework components use AJAX for partial page refresh.  
We evaluated the following component-based frameworks: SwingWeb, WebOnSwing,  Wicket, wingS, Echo2, Oracle ADF Faces, ZK. For evaluation reports, see our  previous posts.  
SwingWeb, WebOnSwing, Wicket, wingS are not AJAX-based.  
Oracle ADF Faces: for 30 simultaneous active users, Tomcat reported an error  (consequence of the thread contentions).  
ZK: the zkdemo-all.war application can not handle 40 simultaneous active  users (CPU overload, max response time is too big). Multiple thread contentions  reported.  

Echo2 is AJAX-based, supports modal dialogs, is component-based and  event-driven. Echo2 also has a very  good performance.So, Echo2 is so far the only framework which passed our  requirements.
Does this mean that Echo2 will eventually become de-facto industry standard  for Web frameworks (replacing Struts)?
Wedon't think so.
There are several problems with Echo2. Theyare all related to one issue:  Echo2 has a Swing-like API. Or let's refrase it: it does not have Swing API,  although it could.This brings us to a very important evaluation criteria: tools  support. NextApp, Inc. (a company behind the Echo2) sells EchoStudio2, which is  a plugin for Eclipse. EchoStudio2 is not a WYSIWYG tool. Since Echo2 API is not  standard, and the framework is not widespread, tool vendors are not developing  visual editors forit. Also, using Echo2 API means for a developer one more API  he has to learn.
IfEcho2 would use Swing API (like SwingWeb, WebOnSwing do), it would bring  the following advantages:
-developers could use many existing commercial or free java IDEs to visually  develop dialogs (every java IDE has Swing editor);
- it would be possible to have a single code base for desktop and Web  applications. This is a dream for many ISVs who have both desktop and Web  applications with the same forms. It would make possible tricks likedropping  Swing application JAR file into Web container andrenderingit as a Web  application (like  SwingWeb does).
- familiar API: if you know Swing, you can develop Web applications. For java  developer, that would also help to answer positively on another evaluation  question: "If you know this framework, will it help you to find a job?".
Weunderstand that NextApp makes money selling EchoStudio2, and if they  changed Echo2 to use Swing API, nobody would buy EchoStudio2. So, it is not in  their business interests.
If Echo2 is not an ideal Web framework, then is it possible to create  one?
Yes!
SwingWeb andWebOnSwing proved that it is possible to render Swing  application as a Web application, but have a poor performance. Echo2 proved that  Swing-like Web application with explicit representation of the complex UI state  on the servercan have a very good performance.
The task is to merge those frameworks. After all, they are all open source  frameworks. No need to write anything from scratch. I would estimate that it  would take three man-year (pessimistic) to do this.
Who could do this?
1. A bigISV/ERP vendorwith existing vertical applications (Oracle, SAP?).  
2. A big java tool vendor (Oracle, IBM?).
3. A big AJAX-tool vendor (Yahoo, Google?).
The upshot for such a vendor would be to have a growingecosystem  aroundtheir products/services,fulfillingthewhole  product requirement: thousands of developers would usetheir framework and  componentsto customizetheir applications, to develop third-party applications  and extensions,to accesstheir services.
The winning framework might become a part of the open source software  stack (JBoss?).
The easiest way for them to do this would be to have the NextApp developers  modify Echo2: buy NextApp or license Echo2 (remember Oracle licensing JBuilder  and developing JDeveloper?).
If someone prefers defining UI using XML, they should use JAXX+ Echo3 (Echo3 = Echo2 with Swing  API). Using  JAXX for UI definition is similar to using Windows resource files for dialog  templates, menus, images, strings etc.
Well, if you need to choose a Web framework now, what should you do?  
Our suggestion: use Echo2; make sure your business logic is well separated  from the UI code, so that when a new winner with Swing APIemerges, you can  migrate without a big pain.Isolating the rest of your code from UI should be  fairly easy:since Echo2 is event-driven, most of the interaction happens in  event handlers.
There are alsomore questions to be answered regarding Echo2:
1. Is it possible to optionally  support non-sticky clustering?
2. Server  Pushis required for workflow applications. How will it affect the  performance of the application? Do we need to develop a custom Echo2 component  (see How  server push should NOT be used)?
3. How Echo2+Spring+Hibernate combinationwill perform? We need to test  performance of the HSE framework.
Related links:  
Java Web Frameworks by  Matt Raible  
Crossing  the Chasm: Marketing and Selling High-Tech Products to Mainstream Customers  (Paperback)by Geoffrey  A. Moore
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