Chapter 2. Basics

This chapters covers some of the basic concepts of the Valkyrie framework. Most of them will be explained in more detail in later chapters, but this should give the framework user a quick overview.

2.1. Getting started using the archetype

Starting development of a Valkyrie RCP application is very easy. There is an archetype which provides a basic skeleton application from which you can start.

To create a project, making use of the archetype, you need to execute 

mvn archetype:generate
   -DarchetypeGroupId=org.valkyriercp
   -DarchetypeArtifactId=valkyrie-rcp-archetype
   -DarchetypeVersion=1.0-SNAPSHOT

This creates a basic Valkyrie application consisting of the 4 basic elements needed to run a Valkyrie application:

  • ApplicationConfig implementation

    This contains the basic elements of the Valkyrie application, such as the ApplicationWindowFactory, ApplicationPageFactory, ... The implementation provided by the archetype uses all the default implementations of these factories. It also references the

  • CommandConfig implementation

    This contains all the commands that will make up the navigation in the application. These can be the commands contained in the menubar, toolbar or any other navigation component.

  • context.xml

    Valkyrie has only a small XML Spring config file, basically defining the ApplicationConfig bean. Valkyrie can work without the XML file, but since some Spring features are still more simple to define in XML than they are in Java configuration, it is included.

  • ApplicationRunner class

    This is the executable class that runs the Valkyrie application.

2.2. The factories

Valkyrie uses the factory pattern extensively to create its objects. Most of these factories are discussed in other chapters, but the following list show a small overview of the essential factories:

  • ApplicationWindowFactory

    This factory creates the window in which components are shown. The standard implementation creates a JXFrame and defines a menubar, toolbar and statusbar by default.

  • ApplicationPageFactory

    This factory creates the 'pages' in Valkyrie. A page is the main contentpane in which components are shown. The default implementation shows a single panel in which components are shown, but there are implementations that show multiple tabbed or docked content panes.

  • PageComponentPaneFactory

    This factory the actual content pane in which the content of a page is shown. The basic implementation shows a simple internal frame. There is also a simple implementation that wraps the content in a panel without decoration.

  • ComponentFactory, ButtonFactory, MenuFactory

    These factories create basic Swing components. The default implementations create the standard Swing components in the JDK (JLabel, JTextField, ...), but other implementations may provide other implementations. When creating components in Valkyrie, these factories should be utilised wherever possible in order to maintain a standardized way of creating components

2.3. Lifecycle

Valkyrie applications have the concept of a lifecycle. The lifecycle can be used to hook in functionality at certain points of execution. The lifecycle dictates when the application window should be created, what should happen before and after creating, when commands should be creating, ...

Lifecycles enable the developer to add functionality to these extension points. For example, a developer could add a login window before the displaying of the application window to enforce security, or to show a confirmation dialog before closing an application window.

2.4. Views

Views are the abstraction of a component shown in a page. A view also has a descriptor that describes the content of the view, such as a title, description or icon.

2.5. Widgets

Sometimes a bunch of components make a logical group and share functionality (say, for example, a CRUD component that takes a list as input and consists of a table, detail form and filtering fields). Widgets provide a way to create such groups of components.

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Chapter 1. Introduction Valkyrie Chapter 3. Applications