Gravity :: home:projects:zebra

On-site WEB application is an application that runs in context of a browser autonomically thus it does not require WEB apps server side technology (JSP, PHP, ASP and others). On-site WEB application may exchange data with remote services.

Zebra unites bunch of the packages that are supposed to be used for building on-site WEB applications. The packages are listed below:

Zebra core JS. Proper OOP paradigm implementation in JavaScript. Packaging, inheritance, abstraction, overriding, overloading, method accessors and many other OOP features are supported.
Zebra Java JS. This is number of standard Java classes ported into WEB. Thinking in Java developing Zebra JavaScript applications can be very handy. For instance, take a look how a text file can be read by applying Zebra Java JS classes:
```
    var stream = new FileInputStream("test.txt");
    var reader = new LineNumberStreamReader(stream);
    var line   = 0;
    while ((line=reader.readLine()) != null) {
       ...
    }
```

Zebra WEB user interface. Powerful and rich set of HTML5 Canvas based UI components. All Zebra UI components are going to be result of transformation Java based Gravity components. The conversion is possible because of well designed architecture and abstraction of Gravity platform. Gravity UI Java based components are free from AWT or SWING dependencies and can be easily adapted for other platforms what has been already proved by porting it to J2ME, .NET and SWT. It is expected developers can implement WEB UI interface as if they are working around standalone application:

   
 ...
 // JavaScript or Java or .NET code 
 panel = new Panel(new BorderLayout());
 panel.add(BorderLayout.CENTER, new Label());  
 ...

Zebra components ported from gravity platform. There many useful, weel designed and lightweight components Gravity platform provides. Zebra is going to have it transformed into JavaScript. Find info following the link: Gravity components
Zebra implements Java to JavaScript converter to port Gravity Java code base component into appropriate JavaScript based Zebra components as fast as it is possible. This the only Zebra stuff which is not going to be distributed under open source license. There is online version of Zebra Java to JavaScript converter is available by following the Zebra Java to JavaScript converter link, or you can find it embedded into next chapter.

To get more information follow one of the link below:

Proper OOP in JavaScript
Thinking in Java writing JavaScript code
Zebra Java to JavaScript converter concept

Here is online application that can demonstrate not only the conversion process itself. Playing with this WEB application it easy to investigate:

how Java constructions are converted into JavaScript code
how Java OOP features are reflected with generated Zebra JavaScript OOP
how some native Java classes are represented in Zebra JavaScript

There are bunch of limitation regarding one to one transformation, but generally it works:

One of the major concept is to have fast and easy way of transformation existent Gravity GUI components code base into Zebra JavaScript Web widgets. This helps to port Gravity components into WEB context with minimal efforts. The core task in this context is developing Gravity Java code converter. Find picture below that illustrates the key taskd:

Milestones are listed below:

JavaScript and OOP. One of the main problem is JavaScript language is not truly OOP language. JavaScript has to get number of special classes to make it close to OOP paradigm. One of the possible solution is use existent implementation. The prototype JavaScript library provides one of the best approach
Java source code parser. Automation tool to convert any Gravity Java GUI component into Zebra JavaScript component saves huge amount of time
Developing adaptive layer for HTML5 canvas element. Adaptive layer is designed to connect concrete implementation (HTML5 canvas element) to Zebra GUI components layer. Roughly adaptive layer knows how to transform events to pass it to components and how to render content

What is Zebra

Zebra Java to JavaScript converter

Zebra project road map