jnex Application Framework for Java TM







 


 

 
 
 

 

Nexirius GmbH

Sonnhaldenweg 66

CH-4450 SISSACH

Switzerland

Tel: +41 61 973 01 23

marcel.baumann@nexirius.ch
 












Architectural Overview


jnex

Application Framework for JavaTM

 
 
 


This document gives a short overview of the classes, which are defined in the Nexirius Application Framework for JavaTM (jnex).














Author:


Marcel Baumann


Version:


3.0


Date:


02.05.02 09:15


File:


U:\data\fw\ArchitecturalOverview.doc







Introduction

This Document describes shortly how jnex works and how you save a lot of programming while loosing no flexibility and code quality. This framework is designed in a way that experienced JavaTM programmers can speed up their application programming time by a factor of 10.


The basic concept allows the complete separation of business objects from the graphical user interface. Business objects can be defined as hierarchical structures and arrays, which are automatically persistent (streamable).



Who Should Read This Document


The typical reader of this document wants to get a short overview of what you can do with jnex and how its components are designed.

Why use jnex?


jnex and Swing™

Swing™ is the part of the Java™ Standard Development Kit. It is a class library which is used to generate interactive visual components like windows, menus, text fields or buttons. It is not easy to cope with all the functionality which is contained in Swing™. And there is always more than one way to achieve a certain result.


This leads to the fact, that the code which is responsible for the GUI is not easy to read it contains a lot of similar sections and it is mixed with the business logic.


jnex relieves the programmer of most GUI programming. The code which is responsible for the layout is 100% separated from the business logic and the look and feel is centralized in the base classes.

jnex and Software Design

jnex changes the process of software design by moving the focus from GUI design towards business object design. The structure and the behavior of the business objects are the first things which can be implemented. The GUI can be generated automatically for the first beta versions.


While the test team is already testing the behavior of the application, the programming team is designing a nice GUI on top of it all.

jnex is not epidemic


Epidemic frameworks lead to the bondage of using the same framework all over. They even force the programming team to change existing code to adapt to the new policies. Not so with jnex. Because jnex can easily live side by side with classic Swing™ components and programming techniques. It is even possible to extend existing applications step by step with jnex components.

The Model View Controller Concept


Goal

The basic idea is to separate the GUI (graphical user interface) code from the BOM (business object model) code. With that strategy the code will be structured in a way that is easier to maintain and understand. Changes in the GUI will not affect the BOM and vice versa.

Basic Idea

In the Nexirius Application Framework every BOM is defined as a hierarchical structure of structures and arrays and simple types. Each structure member has a name, a type, a value and a state. Based on this information the framework can create a GUI element, which is an editor or a viewer for the value.





Type (Data Model)


Default Viewer


Default Editor



String


Label


Text field



Integer


Label


Text field



Floating point number


Label


Text field



File Name


Label


File selection dialog



Bitmap file name


Image viewer


File selection dialog



One out of a list


Label


Combo box



Boolean


Label


Check box



Array


Table


Table with New, Edit, Delete



Method
 


Push button



Structure


Viewer panel


Editor panel



Password


Label (displaying *)


Password editor (displays *)





Events


All the value changes of a data model lead to events, which are sent to the hierarchical parents and to all the attached listeners. The listeners can be the currently attached viewers and editors or other data models, which react upon value changes of a certain elements.



 

Structure Editors

Structures are containers of simple data models and arrays and other structures (sub-structures). They are usually displayed on panels where every structure member is located at a certain position together with a label or a title frame (form).


The location, size, color and font properties of each member are defined in a layout class. If for a certain class no layout is assigned then the default structure editor creates a default editor for every structure member.

Viewer Factory


The Viewer Factory is the heart of the model view controller system. It has a default mapping which assigns default editors and viewers and layouts to data model classes. The user extends this map for his own data models. It is also very simple to extend the viewers and editors with own classes, which handle the display and/or editing of associated own data models.



The Application Framework


Pull Down Menu and Tool Bar

The application framework is a basis for rapid JavaTM application development. The application class uses a text file to create a pull down menu and a tool bar. The command names, which are used in the text file are compared to commands, which are attached to the main data model. If the command exists then the menu button is linked to that command. If the command is disabled then the menu item and the toolbar button are grayed.


Multi Language Support

All the text elements like labels, button texts, menu texts, combo box values are based on resource key strings, which are translated into the actual language specific string at creation time. The property file contains not only strings for the textual information, it also describes the tooltip text and the associated icon of a button or label or text field.

Persistence

All the data models automatically streamable. Based on that fact a class is predefined which handles all the methods like open, save, save as, need saving stuff. It asks before overriding an existing model and it pops up a file dialog when a file name has not yet been assigned.


Popup Editors



It is very simple (one line of code) to create a popup dialog window of any data model with an ok, cancel and help button. The data model is duplicated and a dialog window with the appropriate editor is generated. If the ok button was pressed then the value of the copy model is automatically assigned to the original model (via streaming).