ExtJs: ExtDirect - A Magic

Get Some idea about DJN(DirectJNGine): A java based implementation of ExtDirect Specification

ExtDirect is a magic in ExtJs that enables developer to directly call the server side methods or functions directly on client side(Javascript side). It is a specification and some group of developers in different server side technologies like Java, PHP, Dotnet etc have provided its implementation. Followings are the specification of ExtDirect:

Specification:

§  Remoting methods by metadata – Custom annotations and attributes

§  Programmatic, JSON or XML configuration

§  Type conversion

§  Asynchronous method calls

§  Method batching

§  File uploading

§  Specify before and after actions to execute allowing for aspect oriented programming. This is a powerful concept which can be used for many uses such as security.

Followings are the advantages of using ExtDirect:

Advantages:

Prior to ExtDirect, we could communicate with server by using only Ajax but in this case we have to write several boilerplate codes every time when we communicate with server.

a)      Creation of  AJAX request

b)      Populating AJAX request.

c)       Defining  request success handler

d)      Defining  request failure handler

e)      Submit the Ajax request

But, we can get rid of this boilerplate code by using ExtDirect.

Server side implentations of ExtDirect:

There are several server side implementation of ExtDirect like in PHP, Dotnet, Java etc. Here we will consider about java implementation. Followings are the java side implementation of ExtDirect:

1)      directjngine - Maintained by pagullo (Pedro Soliveres)

http://code.google.com/p/directjngine/

http://extjs.com/forum/showthread.php?t=73027

2)      extdirectspring - Maintained by ralscha

https://github.com/ralscha/extdirectspring

http://www.sencha.com/forum/showthre...t-Spring-1.0.0

3)      extdirect4java - Maintained by piziwate (Steve Guillarmod)

http://extjs.com/forum/showthread.php?t=67956

http://code.google.com/p/extdirect4java

4)      Ext.Direct Struts 2 plugin: extdirectj-s2-plugin - Mainted by stefanorg

http://extjs.com/forum/showthread.php?t=69353

http://code.google.com/p/extdirectj-s2-plugin/

5)      HQExtDirect - Mainted by cattus

A new reflection based Java server-side stack implementation.

Examples, additional information and packages you can find at the project's home page:

http://bitbucket.org/cattus/hqextdirect/

Forum thread: http://extjs.com/forum/showthread.php?t=70619

Following is the comparative study of first four implementations:

Comparative study of Java Stacks of ExtDirect Specification

	DirectJNGine	ExtDirectSpring	Extdirect4java	Ext.Direct Struts 2 plugin
Version	2.2	1.3.1	0.3.2	r3
License	GNU Lesser GPL	Apache license 2.0	GNU Lesser GPL	GNU GPL v3
Document Quality	Good	Good but brief	Not Available	Not Available
Support	Good	Good	Very late response from forum	Very late response from forum
Form Post	Yes	Yes	Not Found	Not found
Duration Based Polling	Yes	Yes	Not Found	Not found
Direct Store	Yes	Yes	Not Found	Not found
Google App Engine Support	Yes	Not found	Not Found	Not found
Servlet Scope Handling	Yes	Yes	Not Found	Not found
Custom Json-Java Serialization Deserialization	Yes	Not found	Not Found	Not found
Automatic Json-Java serialization Deserialization present?	Yes	Not found	Not found but JsonSerializer and Deserializer used in Utils.java class	Not found
Adding Action methods programatically	Yes	Not found	Not Found	Not found
Diagnostic and logging	Yes	Not found	Not Found	Not found
Batch Request Handling	Yes	Yes	Not Found	Not found
Stateful Actions	Yes	Not found	Not Found	Not found
AOP Support	Yes	Not found	Not Found	Not found
Examples	Available	Some clear online examples available	Only one example provided in forum as well as on wiki tab of code link.	Very Limited
Last Build	14-May-12	29 Apr, 2012	May, 2009	May, 2009
Maintained By	Maintained by pagullo (Pedro Soliveres)	Ralscha	Piziwate (Steve Guillarmod)	Stefanorg
URL	http://code.google.com/p/directjngine/	https://github.com/ralscha/extdirectspring	http://extjs.com/forum/showthread.php?t=67956	http://extjs.com/forum/showthread.php?t=69353

Further we will go through DJN i.e. DirectJNGine and will do some hello world program with this in my next post.

Get Some idea about DJN(DirectJNGine): A java based implementation of ExtDirect Specification