Getting started

This chapter gives you a quick start without going into all the details. In a one-hour-tour you will

• Create your first UI within seconds,
• Learn how to design things right using the Decorator pattern
• Define constraints for user input using the Bean Validation standard,
• Improve graphical layouts in a fast and WYSIWYG way,
• Implement user navigation between different masks, and
• Test your application by ordinary JUnit POJO tests

The source code of all examples in this manual is located in directory examples-firststeps of the gengui distribution. Every chapter mentions the sub directory which is relevant for the example. E.g. the directory examples-firststeps/quickstart/hello includes the first Hello World example. Every chapter also includes the required Java call to start the example. In general generic user interfaces are displayed by a call like that:

java gengui.infonode.RootFrame <class #1> <class #2>

To display all examples at once, the call simply must be extended by the class names of the objects to instanciate for display. Most examples also provide a main class to simplify the application start.

IMPORTANT: The directory resources must be part of the CLASSPATH on application start so that the framework can find the individual settings in the form of configuration and layout files. It also contains the file gengui.properties with a reasonable basic configuration for the framework.

Attributes, Properties, Fields and JavaBean Conventions

When working with the gengui framework, it is important to follow the JavaBean conventions for accessing attributes. An “attribute” is a data member of a Java class which – according to the JavaBean convention - is accessed by appropriate getter and setter methods. It is best practice that the identifier following the “get”- and “set”-prefix, corresponds to the name of the attribute, whereby the first letter is capitalized.

An attribute

       private String name;

is accessed from outside the class by the member functions

       public String getName();

       public void setName(String name);

The notation with the leading capital letter is often referred to as a "property" of the class. A class may very well contain virtual properties, i.e. properties that do not refer to an attribute of the corresponding name but e.g. to an assembly or type conversion of other attributes. The actual names of attributes are therefore a secondary aspect. Many frameworks that are based on Java reflection, work with the JavaBean convention and assume its correct usage by the developers - e.g. JPA. This is also true for gengui.

So if this documentation uses the term “property”, it refers to the convention above. The term “field” refers to components on the screen, i.e. a text field, a check box, a combo box etc.

Entries in configuration files like gengui.properties are referred to as "configuration parameters" in this document to keep them clearly separated from the term "property" as defined above.

Created with the Personal Edition of HelpNDoc: Create HTML Help, DOC, PDF and print manuals from 1 single source