Sunday, December 14, 2008

Sanjiv Comment on ppl argue with Pure Gwt and Javascript Wrapper ( SmartGWT )

Compile output size and runtime performance are two separate issues. A
third party widget written in GWT Java, regardless of how small it compiles down
to, doesn't magically make it run fast. Nor does it make it magically render
perfectly on all browsers. As an example a TableGrid written in GWT Java could
still perform really poorly, and not display consistently on all browsers.
There are obviously several aspects to GWT that helps avoid leaks and such
but this does not mean that any third party code written in GWT is
100% leak free. The GWT 1.6 event API is really neat and SmartGWT users
it. Well written code is what will perform well and display consistently
across various browser.
On the issue of performance, there are numerous posts
made by paying GXT users that the performance of GWT-Ext is still better than
GXT. You can search their forums. This is not to suggest that performance
improvements cannot be made in SmartGWT. If you can give specifics, it would
certainly help in resolving them. But without specifics like whether it was the
initial load time, performance of specific widgets etc it will be difficult to
act on. Feel free to post on the SmartGWT forums or create an issue on the
smartgwt google code project.
On the issue of compile output size : The
SmartClient library is extremely stable and developed over the past 8 years.
If you peruse their forums, you will find that pretty much all questions
are met with an answer explaining how the user can accomplish what they're
trying to do. Their library is virtually bug free. I realize this is a strong
statement, but its true. Only some 4-5 issues were patched
post-release. Compare this to the bugs forum of any of
your favorite libraries. SmartGWT will inherit these attributes
once its past the few initial minor releases and issues are flushed out during
this period. Due to the high level of stability of SmartClient, it can be
viewed as the kernel of your web app which should be configured to be
gzipped with an "Expires Never" header for a given version. This means that the
browser will cache the "kernel" (SmartClient JS files) and the only code that
gets downloaded is your application code, and not any code related to the widget
/ framework. Future releases of SmartGWT will provide a GWT linker that only
pulls in the required files so this should cut down the total size of the
The SmartGWT showcase has some 250 samples which is 6 times more
than the GXT showcase so its not quite apples to apples when it comes to initial
load time.
Finally please read my blog entry if
you haven't already done so. I go over the SmartGWT fundamentals, the concept of
a DataSource and how it will lead to a cleaner architecture and can cut
application code significantly. I mention how a master detail page can be
written in as little as 10 lines using a reusable DataSource definition that
describes an entity / model class. Plus the reduced number of lines of code on
the server as well.This is the first release of SmartGWT and while it is quite
stable and has been tested and used by early adopters for the past four weeks,
users can expect any rough edges / bugs / performance issues / better skins etc
to be ironed out over the course of the next few minor releases.As mentioned
earlier, if users have found a library that meets their needs, thats great and
there's no need to look further. And for the others, feel free to evaluate
SmartGWT to see if it helps meet your requirements. If you feel that there are
things that can be improved please post on the SmartGWT forum or create an issue
on the google code project page.

Friday, December 12, 2008

Gwt UI Component with Fluent Interface Pattern

Fluent Interface pattern Fluent Interface is come from Martin Fowler. These types of design pattern are often utilized to create configurations for your objects but can progress into an internal Domain Specific Language or DSL.

I will use GWT as a sample to point out the issue of Swing like development with HTML\tag style for UI programming. In GWT/Swing like coding style, have you found out that the number of line of code is much more than tag style. Look at the following explanation.

Gwt Button with out Fluent Design
Button disabledButton = new Button();
disabledButton.setTitle("Disable Button");
//Come on!!! still set again.. :( ..How many line already!!! that is just one UI component...

HTML / Tag style
All the properties can be in one line and optional.
< button title="Disable Button" width="11" focus=" true" height=" 11" enabled=" false" ensuredebugid="cwBasicButton-disabled" />

Gwt Button with Fluent Design
Button disabledButton = new Button()
.ensureDebugId("cwBasicButton-disabled").setEnabled(false).setWidth("11").setHeight("11").setTitle("Disable Button").setFocus(true) ;

Fluent like coding style is something like tag/annotation style of code. It is good to configure an object.

Constructor way of coding
No wait a minute, We can use Constructor to passin the properties so it can be in one line of code.
Maybe you can create constructor for the Button object with all the properties but how many combination of properties you can create. Bad design because it is not easy to read.
Button disabledButton = new Button("cwBasicButton-disabled", true, true); //what is the true true for? Which one is enabled? Which one is focus?

public Button ( String ensureDebugId, boolean enabled, boolean focus){...}
public Button ( String ensureDebugId, boolean enabled, String title ){...}
public Button ( String ensureDebugId, boolean enabled, boolean focus){...}
// you can create somemore for other properties...if you are hardworking.

Make Button with Fluent Interfaces Design Pattern
So in order for GWT/Swing like coding style to solve all this issues and to minimise the number of line of code and readability. Fluent interfaces pattern has to be implemented.
All the UI component should be coded in the following way. All setters have to return this own for the subsequent statement to call again.

Button SetTitle(String title){
this.title= title;
return this;
Button SetEnabled(boolean enabled){
this.enabled= enabled;
return this;
..// for all the setter of the properties

Button with Java5 Annotation
With the Java5 Annotation support, you can easily configure an object in Attribute Oriented Programming way. But do you think gwt support annotation in runtime mode? The answer is no. But we can use it via gwt generator wich mean in the compile time.
@ButtonProperties( ensureDebugId="cwBasicButton-disabled", enabled= false, width=11, height=11, title="Disable Button", focus=true )
Button button = new Button();

Fluent Interfaces Pattern in SQL
let see how it can be in Sql.
Query = q = new Query()
This can be easily refactor and avoid typo error. Sound good right!!!

Finally, i hope our programming trend is going to attribute oriented programming and fluent Interfaces Pattern. THE WORLD IS JUST CONFIGURE

GWT 1.6 going to release soon

Happy to see that GWT 1.6 going to release soon. Estimated on Q1 2009. Compiler performance improvements is a high demand feature in gwt group from all GWT developer. Hopefully it can reduce the compilation time to 50% and more. Other than that will be Developer Guided Code splitting, to avoid download all javascript at the first load.

Release 1.6

  • New compiled file deployment structure
    • Easily compile into a war file structure, making it easy to deploy your compiled GWT application into standard servlet containers
  • Migration from Tomcat to Jetty hosted mode server
    • A more pluggable architecture for the hosted mode server will enable developers to use servlet containers other than Tomcat with the Hosted Mode browser
  • Uniform event handlers
    • Event handlers will be implemented in a uniform fashion across all widgets, with listeners deprecated
  • DatePicker, LazyPanel migrated in from incubator
    • New widgets from the incubator
  • String performance improvements
    • StringBuilder uses deferred binding to optimize string appends per-browser
  • Compiler performance improvements
    • 1.6 will introduce parallel permutation compilations and other performance tweaks for faster compiles

Post 1.6

  • Developer Guided Code splitting
    • Developer guided code splitting is a mechanism that allows developers to specify asynchronous split points in their code where the code base can be split and downloaded in different chunks. This is currently an R&D project but looks promising.
  • Analysis of compiled code, aka Story of your compile (SOYC)
    • Aims to give developers concrete information about their compiled JavaScript, such as which Java classes are generating the most JavaScript code.
  • In-browser hosted mode, aka Out-of-process Hosted Mode (OOPHM)
    • In-browser hosted mode will allow GWT developers to debug their apps within a browser rather than GWT's hosted mode browser
  • UI Binder
    • The UI Binder will allow the creation of UI elements in a declarative fashion. Watch for UI Binder to land in the GWT incubator soon.
  • Client Bundle
    • Client Bundle implements the power of deferred binding used in Image Bundle in a generic fashion so that it can be used on many resources. These include TextResource, ImageResource, and CSSResource
  • RPC performance improvements
    • Ongoing work to improve the performance of RPC

Wednesday, November 19, 2008

Sanjiv is back with SmartGWT

The God of GWT wrapper is back. Sanjiv is going to wrap another 3rd party UI library which is SmartClient. This time the SmartClient is more rich than Ext Js. But i felt slow when browsing through the showcase. It is still the problem of GWT. Or it because of wrapper wich does not take advantage of GWT javascript optimisation in compilation. Here is the showcare.

After the Issue happened in GwtExt, the first thing we need to see is the licensing issue. SmartGWT and the underlying SmartClient library are LGPL, free for use inside commercial, closed source applications without payment of any kind. Sound ok. Hope he found the right way to go this time.
SmartClient does provide web visual builder also. It sound really comprehensive. Here is the video to showoff.

Some of the points and question coming out in my mind...

1)Is GwtExt going to end soon?
2)It is just the wrapper like GwtExt. It does not fully use the power of GWT like javascript optimisation and more...
3)Can Sanjiv be trusted this time?
If you are just the simple user. you should use SmartClient. If you are professional technology java guy. you should not consider this because you learn nothing. I still will choose ExtGwt. It is because it build up from native google api. We can learn the code from there and change the code if anything happen which you can't do anything with GwtExt and this SmartGWT.

Comparison of Jasper and Birt

There are 2 famous Java Reporting tools which are Jasper( free ) / Jasper server and Birt( free ) from Eclipse/Birt Exchange from Actuate. You can consider the following points when selecting the java reporting for your project.

Drawback of Birt
1) Jasper ui is pixel base so you can get exactly what you see what you get but Birt is not. Issue in receipt printing for those location and allignment is fixed.
2) Eclipse designer problem. You have to erase the whole filter and add again. The changes will not be reflected if you just modify from there.
3) Output is different in Eclipse designer and real deployment when play with complex subreport.
4) White space between row.

Drawback of Jasper
1) The subreport has to use whole row in main report but Birt not neccessary. Not really consider drawback of jasper because subreport is not really useful because of the performance issue.
2) File size is big for embedding to your project because of the wizard and view page (i think).

Advantage of Birt
1) Provide Wizard to create input screen in ajax.
2) View reporting page is provided so programmer no need to code the output screen. But have to do the security part.

Jasper is the winner because it will not create many issue like Birt for programmer.

Thursday, November 13, 2008

Google Docreader : Change root label of tree

At the beginning, the label is follow your project name which can not contain any space. Thus, it can not be meaningfull name for your document description.
After i google arround the world, secret behind is you need to create a wiki page in your google project hosting named DisplayName.