Separate JS content processing logic from JsServlet

Separate the JavaScript content retrieval and the validation to external handler.

The change will allow better customization/extension in addition to UriManager and Versioner without having to make modification to the JsServlet class itself.

This follows the pattern from rest of the Shindig's servlets to allow delegation for execution and make servlet class provide skeleton/flow of execution to make implementers of Shindig dont have override the whole get function.

Highlights of the change:
-) Create new JsHandler class that is responsible to handle processing logic for the request to the JsServlet.
-) Delegate the JS content retrieval from FeatureRegistry to the JsHandler class.
-) Add protected method to the JsServlet for post processing to allow overrideable behavior for checking status and set the response header.

[henry.saputra, 2010-09-03 01:10:37]

Propose changes to separate JS content processing logic from JsServlet to
external JsHandler class.

This change follows the pattern in other servlet to allow more customization via
injection to the JavaScript request via feature aliases.

Please let me know if you guys find any concern or suggestions, review is
greatly appreciated.

Thanks.

- Henry

[henry.saputra, 2010-09-04 00:48:41]

Added dev@shindig.apache.org to the reviewers.

[Paul Lindner, 2010-09-04 06:30:53]

looks good, just minor stylistic suggestions..

http://codereview.appspot.com/2104046/diff/21001/22001
File
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java
(right):

http://codereview.appspot.com/2104046/diff/21001/22001#newcode188
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java:188:
* GagdetContext implementation for JsHandler which is called by
FeatureResgistry.
spelling nit... s/Resgistry/Registry/

http://codereview.appspot.com/2104046/diff/21001/22001#newcode199
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java:199:
public RenderingContext getRenderingContext() {
extra indent here..

[henry.saputra, 2010-09-04 06:54:39]

Resolve issue/suggestions from Paul.

Uploaded the latest patch file.

- Henry

http://codereview.appspot.com/2104046/diff/21001/22001
File
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java
(right):

http://codereview.appspot.com/2104046/diff/21001/22001#newcode188
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java:188:
* GagdetContext implementation for JsHandler which is called by
FeatureResgistry.
On 2010/09/04 06:30:54, Paul Lindner wrote:
> spelling nit... s/Resgistry/Registry/

Sorry, will fix the spelling errors =(

http://codereview.appspot.com/2104046/diff/21001/22001#newcode199
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/JsHandler.java:199:
public RenderingContext getRenderingContext() {
On 2010/09/04 06:30:54, Paul Lindner wrote:
> extra indent here..

Fixed it, thank you.

[Paul Lindner, 2010-09-04 07:30:56]

ship it!

[henry.saputra, 2010-09-04 16:36:09]

On 2010/09/04 07:30:56, Paul Lindner wrote:
> ship it!

Thanks for the review Paul. 
Changes checked in with svn commit: r992634.

- Henry