The Rich Client Mapping Application
This article's rich Java mapping application consists of only three classes, all of which are located in the ca.ansir.app package. MappingApplication is the main class and extends JFrame. The following code shows how the Map is created and added to the layout of the main class.
public MappingApplication() {
super("Mapping Application Client");
URL url = XMLTileFactoryParser.class.getResource("helloworld.xml");
StringBuffer message = new StringBuffer();
xmlTileFactory = XMLTileFactoryParser.getXMLTileFactory(url
.toExternalForm(), message);
if (xmlTileFactory == null) {
throw new RuntimeException(
"Programming error: Could not find helloworld.xml");
}
map = new Map(xmlTileFactory, 0);
map.setPreferredSize(new Dimension(550, 400));
JPanel contentArea = new JPanel(new BorderLayout());
contentArea.setBorder(PanelUtility.GAP_1X_PANEL_BORDER);
contentArea.add(map, BorderLayout.CENTER);
getContentPane().add(contentArea, BorderLayout.CENTER);
setUpMenu();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
For an initial XMLTileFactory, you'll use the helloworld.xml configuration from Part 2. Your parser class, XMLTileFactoryParser, creates an XMLTileFactory for you. The XMLTileFactory object will always contain a list of one or more XMLTileFactoryInfo objects and the index of zero will always safely index the first XMLTileFactoryInfo object in the list. Your Map object is constructed using the XMLTileFactory and the index of zero to specify the first XMLTileFactoryInfo object.
Before the constructor ends, it invokes the setUpMenus method (Listing 1). The setUpMenus does three things:
- It creates the application's menu bar, and then adds a file menu with an exit action to it.
- It creates a
viewMenu member which is added to the menu bar. The view menu is then configured and reconfigured each time a new XmlTileFactory is used, so a separate method is used to set up the view menu's items.
- It adds a tools menu to the menu bar.
In the setUpViewMenu method, create a radio button menu item for each of the one or more XMLTileFactoryInfo objects in your list. Each of these radio button menu items uses an instance of ViewItemListener which encapsulates the corresponding index in your list. You'll use the TileFactoryInfo metadata (discussed in Part 2) for the name and tooltip of these radios. Selecting one of these radios invokes the map's setTileFactory method along with the appropriate index. Finally, add a separator to the view menu and a check box menu item to show and hide your map's mini map.
So, you know why you created a separate setUpViewMenu method and what that menu does, but you don't know how to invoke the method multiple times. This is where things get interesting. Earlier, you saw that one advantage of using an XML configuration for tile URL generation is the ability to update or plug-in new configurations without recompiling the Java code.
The tool menu provides the mechanism to demonstrate how a new XML configuration can be selected on the fly. Your TileFactoryDialogAction shows the TileFactoryDialog (Figure 1), which is the second class in the ca.ansir.app package. When the TileFactoryDialog is closed (and if a new XMLTileFactory has been selected in the dialog), then you invoke the setUpViewMenu dialog again and the new configuration becomes available to the application.
Figure 1. TileFactoryDialog: Here shown with MappingApplication in the background.
The TileFactoryDialog has a help button, which takes youto a list of test XML configurations. The TileFactoryDialog's preview button shows a preview of the selected XML configuration. The TileFactoryPreviewDialog (Figure 2) is the third and final class in the class in the ca.ansir.app package.
Figure 2. The TileFactoryPreviewDialog: This shows a preview of the selected XML configuration.
The code for the final part of this series is available as an Eclipse project here. Depending on your Eclipse environment, you may need to change the build path to use a specific jdk1.5+ installed on your system. Alternately, there is an Ant build.xml file to build and run the project.
Your rich Java mapping client was motivated by the need identified in Part 1. Leveraging the SwingX-WS project's JXMapKit with the XML configuration and code developed in Part 2, your mapping client demonstrates that new mapping configurations can be plugged into a rich Java client on the fly without the need to recompile Java code.
About the Author
Dan Andrews is the President of Ansir Development Limited. He has been a Sun Certified Programmer for the Java(tm) 2 Platform since 1999. Prior to founding Ansir Development Limited in 2005, Dan worked at SED Systems as a programmer analyst. At SED, he worked on building large Swing applications which help control some of the world's largest satellite networks and deep space antennas.
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