Are you using java with Ext?

[br8kwall]

Quick poll.. please vent on your experience here.


How are you using Java with ExtJS?
DWR, Spring, From scratch...

What is your backend data source?
XML file, MySQL, Oracle, nothing...

How many forms does your app have?

How big is your dev team?

What things did you do right in building your app?

What things did you do wrong in building your app?

Would you use Ext again?

[ElliotS]

How are you using Java with ExtJS?
DWR, with a custom DWRProxy and RecordForm (that takes in/returns a javascript objects, which are converted to/from java by dwr).

What is your backend data source?
Hibernate/Mysql (uses hibernate metadata for ext record fields)

How many forms does your app have?
>100.... =), not including any admin crud stuff.

How big is your dev team?
4 developers + ui guy

What things did you do right in building your app?
DWR "just works". Brilliant. And made all data access using cross-domain dynamic script tags during dev... dont need to deploy frontend... it just works on your own machine. Real time saver.

What things did you do wrong in building your app?
Spent too long trying to do complicated things with ext before realising it was just the wrong way to go or ext already did it. The best advice I can give is if you are trying to do something that seems too complicated... it is.

Would you use Ext again?
Absolutely. It's amazing work. Looks great, works great and written for developers to extend.

[loeppky]

How are you using Java with ExtJS?
DWR for our newest application, Struts for our previous.
What is your backend data source?
Hibernate/Oracle
How many forms does your app have?
30
How big is your dev team?
3 SDEs, but we work on many other things besides the UI to our web app.
What things did you do right in building your app?
Using DWR over Struts is a big win. Modularizing our code into classes, where each class is its own file. In deployment, we will "build" all these JS files into one file for performance. We're implementing many of Steve Sounders "High Performance Web Sites" techniques. Good stuff.
What things did you do wrong in building your app?
In our previous web app, we were using Struts and we didn't separate our classes into separate files. It's not good having one big file with a bunch of classes. Doh!
Would you use Ext again?
Of course. We're getting a lot of other teams in our company to start using it to :)

[tjstuart]

How are you using Java with ExtJS?
Tomcat w/servlets which manage comms with a 4GL Progress environment.

What is your backend data source?
Progress with all screen information described in XML

How many forms does your app have?
Unlimited. Depends on the client database. All our forms are dynamic and are retrieved from the database. Nothing in our application is hard-coded.

How big is your dev team?
3 people. One on java/tomcat. One on Progress 4GL. One on Ext UI.

What things did you do right in building your app?
This is our 4th version of a legacy web based application. So we have learned alot in the last 8-10 years. Selecting Ext was probably the single most "correct" thing we did.

What things did you do wrong in building your app?
Should have moved to Ext2 when it was in alpha/beta stage. Our app is still based on Ext1.1

Would you use Ext again?
Definitely. Especially for static/fixed user interfaces.

[Animal]

How are you using Java with ExtJS?
JSPs with custom tags built with detailed knowledge of Ext so that they integrate into our application.

DWR for Ajax comms, key lookup, ColumnModel creation, Grid population etc.

What is your backend data source?
Hibernate

How many forms does your app have?
Less than 100 now, but the legcay, non-web app we are replacing has thousands...

How big is your dev team?
Me, one other developer, and one of the directors who built the old system, and has no clue about OO/Java/browsers/HTTP/Ajax 8-|

What things did you do right in building your app?
Select Ext for the UI

What things did you do wrong in building your app?
Allow ourselves to be bounced (by a developer who is no longer with us) into starting with old stuff like Struts, experimenting with Backbase and Dojo. Blind alleys all.

Would you use Ext again?
No doubt. It has the simplest, yet most elegant and extensible widget set out there. But it also has a base set of Javascript foundation classes which are better than most of the other offerings out there (I'm thinking of how jQuery like to say their stuff is so small - but it's just foundation classes!)

[chazmatazz]

How are you using Java with ExtJS?
Our backend is written in Java which has a SOAP interface. Currently the SOAP is consumed by PHP, which then powers ExtJS, but I am advocating a switch to Java servlets. (We must provide a SOAP interface, so that part is fixed.)

What is your backend data source?
SOAP, Java Persistence

How many forms does your app have?
50ish.

How big is your dev team?
3. One UI person, 2 backend developers.

What things did you do right in building your app?
Choosing ExtJS is proving to be a good choice.

What things did you do wrong in building your app?
Too early to say.

Would you use Ext again?
Yes.

[br8kwall]

Thanks everyone for your responses. Very good information all around. Are the apps mentioned here all intranet apps? Or are some available on the public web? Are there any URL's available?

[thejoker101]

I'm also curious, I'm starting to use Ext with Java and the application makes a lot of calls to servlets which insert/update objects in the database with Hibernate. Are you guys using DWR to make this a lot easier and if so how? I've seen there's Hibernate stuff for DWR, but
I'm uncertain how far you can take that. Can any of you give a flow example of how your DWR stuff goes?

[Animal]

We don't use any of DWR's addon stuff. DWR has some javascript "utilities" which fall far short of Ext's abilities, and are frankly a waste of time. I suspect the integration of Hibernate into Ext might be similar. We use DWR for its core ability to marshal parameters, and make calls.

We have Java service classes which are exported to the browser for widgets to make use of.

For instance GridHelper.java contains methods to do a lookup of an entity type given a partially typed key. It returns the number of matches, the column value matched against, and the descriptive field from the entity (We have our own annotations which give every entity a descriptive field, and a primary key field. Both are used for matching), so for example, looking up a country, the user may type "US", or "United states", and the same single row will be found and returned.

GridHelper also offers a call to create a server-side ViewProvider object which handles queries and provides a "view" of an entity, meaning column order, width and visibility. It returns metadata needed to both create a Record constructor, and a ColumnModel.

[br8kwall]

This is interesting because now my people who are going to use Ext are saying that it will be easier to implement what DWR does from scrtach.

Can anyone comment on when it makes sense to use DWR versus rolling your own? Or do even the smallest Java-backend apps benefit from DWR?

Does anyone wish that they had/had not used DWR? Why?

[Animal]

You could write the core RPC capabilities of DWR specifically using Ext on the browser side, and rewrite the server-side calling and marshalling and javascript generation code. That would be cool. The Javascript both supplied and generated is just not as smooth and well structured as Ext. It sort of matches the link-up that DWR now has with Dojo... both just a little flaky and too early.

It will be a very big job though.

I would like to see it done. There are some serious shortcomings in DWR. The code to unmarshal references on the server side just doesn't fully work. If you send a parameter which is an object hash, one of who's members is a string Array, it can't handle it on the server side.

An Ext-specific RPC protocol with backend classes which handled C# and Java, and exported target classes to the browser using code generatin. Now that would be a killer app.

[boz]

I ran into an IE+DWR+Polling memory leak that is described here (http://bozmoz.blogspot.com/2007/12/dwr-ie-memory-leak-related-to-timeout.html). When I posted the problem to the DWR list it got no resonse. :( ... I say ":(" because I really like DWR. Now I just can't recommend it for apps that use lots of polling or (maybe) have very very VERY long-lived pages. ... Please don't think I'm evangelizing against DWR.

btw: I haven't used extjs yet but it sure looks interesting. :)

,boz