nt pane displays help topics. The navigation pane is a tabbed pane that lets a user select from among the table of contents, index, and text search options.
Java Help permits a single help system to support varying "navigational views" of help content. The navigational view is a description of how a particular kind of content is to be viewed. In that sense, it is metadata -- data about data. For example, a navigational view is defined by (among other things) its format (how it is to be shown) and data that identifies the format and location of the view. A navigational view is implemented by a Help Navigator, which is a subclass of the JHelpNavigator class (a swing component).
The Java help system already understands several n
avigational views. The table of contents, index, and search information (displayed in the help viewer) already have navigational views defined. Java Help provides mechanisms for registering new navigational views. Consequently, the diversity of data permitted, and the means by which the data is viewed, is limited only by developers' imaginations.
The data structure that carries all the information needed to provide a view into a help system is bundled into a HelpSet file. Note that there are two "loose" terms at use here. First, a HelpSet file isn't necessarily a file, in the same sense as files that you store on your hard disk. A HelpSet file could be bound into an application, for example. Second, it's probably more accurate to say that the information is rooted in the HelpSet file. The structure of a HelpSet is XML-encoded (Extensible Markup Language) data. The data points to the URLs from which you can find the info necessary to build the help system.
Here's an example. One portion of the HelpSet
file points to yet another structure called the Map file. A Map file is a series of "key = value" pairs. Each key is a help topic (i.e., an entry from the table of contents), and the value is the URL of another file that stores the actual content that the system will display when the user selects a table-of-contents item.
The upshot is that the data structures used by a Java help system are flexible enough to permit a wide variety of delivery scenarios: Help can be bundled into a JavaBean, help can be inside an application, help can be a separate (but local) file outside the application, help can be pulled in from across the network, and so on. The architecture is initially daunting, but it looks as if it will serve the broad (and ever-broadening) needs of Java applications and applets.
So, Help Me, Java
