First of
all, let me introduce myself briefly. I am a software engineer with more than
10 years java projects development experience. I am a software architect who
pays attention to the common architecture NFQ stuff like dependency, code
qualification, application maintenance, etc. And, last but not least, I am
technology trend follower who sticks with the “moving” of modern software
development.
Today I
want to talk about GWT because I have done some researches while I am preparing
a fresh new web application development. And I want to use this opportunity to
give a new glass to some pure Java guy to let them know a little bit more about
what is going on with JavaScript recently.
It is very
interesting to read the discussion of using/ not using GWT:
- Some people put hard word, e.g. “GWT is dead”, “Google is dumping GWT”.
- Some people tried to be neutral, e.g. “GWT is not as bad as I thought it was".
- Company behind the current GWT shows us a brilliant report and tells us “89% of respondents would use GWT on their next project”.
Today,
almost one year later after Jochen Krause posted his blog, according to my
personal research, I am afraid I have to agree with him and Guy Nirpaz.
Google has dumped GWT and GWT is dying.
I feel
sorry to say that since the report from Vaadin has actually confirmed that GWT
is a good choice for a new project. Well, the report is brilliant. But while I
was reading it I could not stop asking myself why such a report should even
exist. Ever see any similar report of JQuery, HTML5 or Hadoop recently? No?
Why? Because it is not necessary! Such a report of GWT is trying to let the
people calm down and remove the fear we have while considering using GWT on the
next project. This is just my personal opinion, sorry about that.
GWT has
left Google since 2012. Some people said it is good for GWT regarding the similar
movement of Eclipse from IBM to open source community. But in my personal
opinion they are not comparable. First, Eclipse is a platform while GWT is just
a framework for web application. Second, after moving to the open source
community, Eclipse is still heavily used in IBM. I don’t see the same thing
happens in Google. Google has actually abandoned GWT and embraces pure JavaScript
with HTML5 development and provided Angularjs and Polymer. The community is mad on Angularjs after they met it.
It was a
great choice to choose GWT a few years ago while JavaScript was ugly and just
toy language used for some fancy animation. Now JavaScript is mature enough for
serious project development. It is in fact already used to build some amazing
applications like Gmail, Blogger, Google+, etc. Let me show you why you should
NOT use GWT for the new project anymore.
Google walks away and community is following
I haven’t
seen any life signal of GWT for new project within the Google territory. People
follow when Google walks away.
Enterprise application development environment
This is the
most frequently talked reason for choosing GWT instead of an appropriate
JavaScript framework like Angularjs. You will be benefit from mature
development environment and java language itself. Well, that is correct. But
recently JavaScript and its development environment become more and more
mature:
IDE – Webstorm
Tools mamangement – NPM(Node
Packaged Modules)
Build tool – grunt
Dependency management – bower
Unit test – Jasmin
QA code analysis – jshint
Modular – RequireJS
Framework - AngularJS
In some
areas using JavaScript is even better than developing application in java.
Consider what would be done if maven should be updated and what would be done
if Yoeman should be updated? Much easier while using NPM right?
Object
oriented programming
Many people
have concern about JavaScript language itself. This is one reason why they
consider using GWT. To be honest, just because JavaScript is a dynamic language
does not mean it is not object oriented. You can find many JavaScript OOP
tutorial, for example this one from MDN. There are many JavaScript designpatterns can be implemented in JavaScript,
even beyond the GoF design patterns. Want to read some good books? Take a look
at the post “Required JavaScript Reading”, Rey Bango did a really great work!
Short of
JavaScript experience
GWT lets
people work with java to build a web application running on the client side. Feel
great right? But, look out! JavaScript code will be generated. We do not really
get ride of JavaScript. We are end up with generated JavaScript code! It would
be not true, if you think you don’t need to know JavaScript when GWT is used in
your project. In fact, According to my personal experience, almost every GWT
developer knows JavaScript. That makes me, as a software engineer, feel really
bad. Why should you let GWT generate the JavaScript that you can write it on
your own? In fact, the gap between Java and JavaScript is not as big as people
image. It might take some time to understand some core dynamic language
concepts like “closure” and “prototype inheritance”. The rest should be really easy for mature Java developer to understand. If
you are confused at first glance, maybe you need to learn it three times.
The native
language of web application is JavaScript. HTML is going to provide more and
more API. People around the world are contributing great frameworks/libraries
using JavaScript directly. It is difficult for GWT to follow these fast and
flexible developments done by a more tremendous community. If you want to use
them within GWT, you (or somebody else) have to make them available in the GWT
way. Such a restriction makes me feel really bad. There is really no excuse
anymore not to use JavaScript directly.
GWT is a
mature framework which provides great features like MVP, data binding, etc. But
now, thanks of AngularJS, you will have these features too while using
JavaScript. And that is not enough, beyond these features, AngularJS provides
some other excellent built-in features, e.g. dependency injection (like Guice
does) and Directive which is the killer feature of AngularJS for customization
and component integration.
Testability
Still think
GWT is the only choice for building testable client side RIA? Now is the time
to change your mind. You can test every thing by using AngluarJS, Jasmin, and
Karma. For example:
- it('should say hello', function() {
- var scopeMock = {};
- var cntl = new MyController(scopeMock);
- // Assert that username is pre-filled
- expect(scopeMock.username).toEqual('World');
- // Assert that we read new username and greet
- scopeMock.username = 'angular';
- scopeMock.sayHello();
- expect(scopeMock.greeting).toEqual('Hello angular!');
- });
Reference:
The
usage of scopeMock via DI and the expect() method looks really familiar for us
Java guys, right? :-)
Widgets
Want to use
some fancy widgets built by other guys? With GWT you have actually only one
choice: GXT. Vaadin could be another one if the complete client-side API isavailable.
With AngularJS the Directive feature make it possible and easy to integration
any other JavaScript widget library. AngularJS co-creator Miško Hevery hasmentioned that AngularJS 2.0 will work with Polymer seamlessly. Is the trend now not clear enough
to you?
Mobile app
development
Hot topic. It
looks like currently everybody wants a (web) mobile app. If you use GWT, you will
have no other choice but mgwt teams up with gwt-phonegap. And the project
gwt-phonegap shows us exactly the risk of using GWT for new project - You have
no direct access to the generated JavaScript and it is painful for any
extension and integration. Why I am saying that? Because PhoneGap provides its
features only via JavaScript API and you are forced using gwt-phonegap to
generate the appropriate JavaScript code, which can call phoneGap JavaScript
API. This approach is painful. If you want to use a new xyz web technology
built in JavaScript, you have to keep waiting until someone developed a gwt-xyz
project or you must develop the gwt-xyz project on your own. Can you afford it?
Some people might say you can use JSNI. Yes, you can! But please think about
it, why use GWT if you want to call the JavaScript API directly? Using JSNI you
will lose most benefits you have because your project is not a pure java
application anymore.
If you have
GWT project and consider build a mobile web app as a new client view, before
you decide to use mgwt and gwt-phonegap, you should at least keep an eye on the
development pulse of both projects:
Still don’t
get it? Compare with the pulse of JQuery Mobile:
Have you
seen the risk of using mgwt and gwt-phonegap in a serious project?
Please
don’t get me wrong. Daniel Kurka did a great work. His work of the both
projects makes a mobile app of GWT possible. He should get our full respect.
But, business is business, you should think of your own benefit and risk.
Summary
If you
currently want to develop a new client side RIA, still using GWT might not be
the best choice, even if you have GWT project experience. For your long term
benefit you should consider using JavaScript directly. If I were asked to build
an enterprise RIA now, I would use the following architecture and technology
stack:
- Architecture: SOFEA
- Server side: Java & Restful API (I am still a Java guy and Java is still the first choice for the backend of enterprise application.)
- Client side: AngularJS, RequireJS, HTML5, JQuery Mobile for mobile web, Cordova for hybrid app, some other JS libraries depends on the concrete requirement.
- Development Tools: maven or Gradle for backend Java project. NPM & Yoeman for frontend JavaScript project.
- Test: Junit & mockito for Java project. Karma, Jasmine, and PhantomJS for JavaScript project.
- CI: Jenkins
