Hdir Applet

Class files: Hdir.class and Node.class

Applet Parameters:

data_url	Location of data file that defines the tree structure. See instructions below on how to create these files.
debug	Print debugging info? Defaults to "no".
palette	Define a color palette, referenced by palette index from 0 to length(palette)-1. Defaults to palette[0]=white, palette[1]=black. Syntax: comma-separated list of hexadecimal color-values. color-values are in the form "#rrggbb".
bg_color	Background color palette index, defaults to 0.
hilite_color	Hilite color palette index, defaults to 1.
context_url	Node URLs are merged against this absolute URL. Defaults to the document base.
font_size	The size font used, defaults to 10.
x_space	The amount of indentation space, defaults to 15.
y_space	The amount of space skipped between lines, defaults to 15.
start_node	Start by selecting this node, optional.

Creating Hdir Data Files

Class files: HdirCreator.class and Node.class

HdirCreator is a Java application that creates data files for use by the Hdir applet. A tree is defined by a text file ending with the .nodes extension. Nodes are referred to by node ids, unique strings that are not visible in the tree display. Node files are formatted as follows:

• The first line defines a list of top-level nodes. This is a comma-separated list of node ids.
• This is followed by one or more node definitions. Each node definition consists of two lines. The first line of a node definition consists of only its node id. The second line observes the following syntax:
  display-name, font-color, url, target-frame, expand, nodes
  display-name string representation of the node.
  font-color palette index for font color, empty defaults to 1.
  url URL relative to context_url, empty for no hyperlink.
  target-frame target frame, empty defaults to "_self".
  expand "yes" or "no", denoting the initial display state.
  nodes comma-separated list of subnode ids, empty for no subnodes.
• There must be no other lines in the text file.

Once a nodes file is ready, it can be used to create an Hdir data file. Data files end with the .data extension. The data file contains the same information as the nodes file, formatted so that the applet may read it more quickly. A data file is a binary file and should be treated like an image when it is copied to a new location. The location of this file is supplied as the data_url parameter to the Hdir applet.

HdirCreator can be invoked in two ways, on the command-line or as a window.

From the command-line:

% java HdirCreator input.nodes output.data
Parses the information in the text file input.nodes and writes a new binary data file. The data file may then be used by the Hdir applet.

% java HdirCreator
Opens a window that provides the same functionality of the command-line interface.