Program Overview & Structure

The program is a Java applet and runs in a web-browser, and can be seen in Figure 4.1. The web-server must be the same machine that runs the route-server, and must already have the map image available for download. The applet can be used to create a new file or edit an existing one. The layout is similar to the end-user software, with a combined text-entry and status bar at the top, buttons below that, and when appropriate, the map at the bottom. The buttons available change as the program moves through its various modes, with typical operation as follows.

Figure 4.1: The Initial Definition Tool

1. If a new file is to be created, the image filename is requested. If an existing file is being edited, its filename is needed.
2. The map is displayed, with the node positions superimposed upon it. Clicking on the map creates a new node, and its name is requested. Right clicking a node deletes it. Options to delete all nodes, and to set the area taken up on the map by each node are available. Another button moves to the next stage.
3. Next the lines are defined (or line definition file loaded). All defined lines are superimposed upon the map, with one highlighted. A button can be used to cycle through these, and another delete the selected line. Pressing new will allow a series of nodes to be selected and named as a line.
4. When all the lines have been defined, the information is sent to the server, which creates the nodelist file. Depending on the server configuration, this may immediately be used by all client software.

Like the end-user software, the applet is split into user-interface, network and nodelist sections. The networking section is designed in a very similar fashion to the end-user software, described in Section 3.3.2. The nodelist section uses the same code as the end-user software (Section 3.3.1), and extends it to allow for the line definition. There is a class that defines a line as a collection of nodes and provides methods to add, remove and search for them. Another class holds a list of all the lines, and loads them from the web-server.