Introduction
OpenJean is a Pure Java® application. It should run on any platform which will run a JVM (Java Virtual Machine) version 1.4 or higher. This includes all varieties of Windows from '98 on, MacOS and most varieties of Linux and Unix.
OpenJean consists of a framework into which can be slotted a number of applications. Each application manages or organises one type of information. OpenJean provides a number of components to view, navigate and organise the information in an application. The two main ones are the Catalog and the Attribute Display Panel.
The Catalog
The catalog provides an outline view of the structure of your information. It allows you to see the relationships between items of information and navigate between them. The catalog looks like the familiar tree as used in, for example, a Windows Explorer. It does have a very important difference however. The underlying data structure is a DAG (Directed Acyclic Graph) rather than a Tree, which means that one item of information can appear in many different places, with many different navigation paths.
This powerful concept becomes more important when we consider the three types of node that appear on the graph. Instead of the usual folders and files we have categories, groups and items. You may choose your own names for these types but the purpose remains the same, to organise items into categories, with one item possibly belonging to many categories, and to be able to group items together for a variety of purposes.
The Attribute Display Panel
Each category, group or node can have attributes which are either bits of information themselves or pointers to bits of information. OpenJean has a very rich variety of types for attributes, including audio, video and image as well as the more usual integer and string. Where an attribute is information in its own right then it will be displayed on the Attribute Display Panel. If an attribute refers to an object which has a specific action associated with it then the Attribute Display Panel will display a button which, when pushed carries out that action. So for an audio attribute, which refers to an audio clip in a file or on the Internet, pushing the button will play the sound. Attributes are organised into pages for convenient display.
One important type of attribute is a reference which points to another attribute in a different node in the same or another application. For example in Calendar one attribute is the person who is participating in an appointment. This is a reference into AddressBook which contains all the details of that person. Calendar displays the person's name and by tabbing over to AddressBook you see all the other details.
Operations
OpenJean has many built-in operations. Because some operations are powerful and could damage your information if used incorrectly openJean operates in two modes, User and Administrator. Only while running in Administrator mode is the full range of operations available, users are restricted to a subset defined in a configuration file. Operations include adding and removing nodes and searching. Nodes can be linked, that is items placed into groups or categories, groups placed within other groups or categories and categories within other categories. It is even possible to add or remove attributes or whole pages. The application Object Base can be backed up and restored, or a part can be exported to be imported into another openJean installation.
Extensibility
OpenJean is extensible in many ways. It is possible for menu items or buttons on the Attribute Display Panel to call your own java code, either to extend openJean or to integrate more closely with another application. OpenJean has a published API (Application Programmers Interface) so that this code can make full use of the power of openJean. The openJean components are all forms of standard Java components so that they can be built into an application if desired. OpenJean stores its information in industry standard XML (eXtensible Markup Language) with a published schema. This makes openJean information directly available for use by other applications.
For example openJean has a special ETV (Export-Transform-View) operation where a built-in or user-supplied XSL (eXtensible Stylesheet Language) file is used to transform the XML exported by openJean into HTML (HyperText Markup Language) for display in a standard web browser.
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