PlaniSphere. Creating a plug-in for PlaniSphere.

Transcription

1 Creating a plug-in for PlaniSphere Creating a plug-in requires a developer to implement SpatialPlugin and SpatialPluginFrame interfaces (see Figure 1). The SpatialPlugin interface defines methods that are required by the plug-in infrastructure to manage the plug-in. If this plug-in needs to have its own window than the SpatialPluginFrame interface must be implemented. The SpatialPluginFrame interface defines methods for managing the plug-in window. If the plug-in that you are developing needs a window than you must implement both interfaces, that is SpatialPlugin and SpatialPluginFrame (see MyPluginWithFrame in figure 1). If the plug-in that you are developing does not need a window than you must implement one interface, that is SpatialPlugin (see MyPlugin in figure 1). For a complete implementation of a plug-in please see the WikipediaPlugin in the Coding a New Plugin section. Figure 1: Implementing a PlaniSphere plug-in Page 1 of 8

2 Pros of the Plug-in Infrastructure The plug-in infrastructure is entirely separate from PlaniSphere. That means that its source code is independent of PlaniSphere and it is also packaged independently of PlaniSphere. The plug-ins that are created using this infrastructure can be used by any application that uses this plug-in infrastructure. Demo Plug-ins There are three demo plug-ins developed: NMEAPlugin, SysInfoPlugin and WikipediaPlugin. SysInfoPlugin is the simplest plug-in. It provides information with regards to the Java virtual machine that the application (PlaniSphere) executes within. This plug-in is used to test the functionality provided by the SpatialPlugin and SpatialPluginFrame. This plug-in does not interact with the map. The NMEAPlugin is used to test the SpatialPlugin interface, SpatialPluginFrame intrface and also the SPI provided by the SpatialPluginServiceImplementation interface. NMEAPluginplug-in can load any NMEA text file produced by any GPS/Glonass/Galileo receiver. The path from the NMEA text file may be displayed on the virtual globe. This plug-in tests the interaction of the plug-in with a newly created layer that displays location information in the virtual globe. The WikipediaPlugin is a plug-in that has functionality that is beyond the scope of testing for the plug-in infrastructure. The WikipediaPlugin can extract spatial data from Wikipedia using the Wikipedia GeoData extension. Documentation using Wikipedia s GeoData extension is available at The WikipediaPlugin will extract spatial information and will plot it on the map. It will plot points of interest and label them. In Figure 2 the POI are extracted from Wikipedia. The POI are the red markers and the light blue labels. Wikipedia, a social networking site may be used as a source for geospatial metadata. Page 2 of 8

3 Figure 2: A Bing Aerial base layer with an OpenStreetMap overlay layer. Coding a New Plug-in Creating a new plug-in is extremely easy. The plug-in developer needs to implement the SpatialPlugin interface and the optional SpatialPluginFrame interface. The code that represents the plug-in needs to be packaged as a jar file. The code for the Wikipedia plug-in is available in Listing 1. The plug-in Jar file can be loaded by the plug-in infrastructure by modifying PlaniSphere s config.xml. Listing 2 exhibits the configuration requirements for PlaniSphere s config.xml used to load the Wikipedia plug-in. Listing 1: The Java code representing the Wikipedia Plug-in implementation package com.zerotrak.plugin.examples; import com.zerotrak.plugin.genericmapmarker; import com.zerotrak.plugin.plugindata; import com.zerotrak.plugin.spatialplugin; import com.zerotrak.plugin.spatialpluginframe; import com.zerotrak.plugin.spatialpluginserviceimplementation; import com.zerotrak.plugin.spatialpluginversion; import java.awt.event.actionevent; Page 3 of 8

4 import java.awt.event.actionlistener; import java.io.ioexception; import java.io.inputstream; import java.net.malformedurlexception; import java.net.url; import javax.json.json; import javax.json.jsonarray; import javax.json.jsonnumber; import javax.json.jsonobject; import javax.json.jsonreader; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.springlayout; /** * mihal */ public class WikipediaPlugin implements SpatialPlugin, SpatialPluginFrame, ActionListener { private final String layername = "Wikipedia"; SpatialPluginServiceImplementation spsi; boolean pluginstatus; JFrame frame; private String vendor = "ZeroTrak"; private String description = "A plugin for displaying points of interest from Wikipedia."; private SpatialPluginVersion version = new SpatialPluginVersion(0, 1, 0); JButton extractpoibutton; JButton clearpoibutton; public WikipediaPlugin() { pluginstatus = false; frame = new JFrame("Wikipedia POI Extractor"); JLabel titlelabel = new JLabel("Wikipedia Extractor"); JPanel titlepanel = new JPanel(); titlepanel.add(titlelabel); extractpoibutton = new JButton("Extract POI"); extractpoibutton.addactionlistener(this); clearpoibutton = new JButton("Clear POI"); clearpoibutton.addactionlistener(this); SpringLayout layout = new SpringLayout(); Page 4 of 8

5 frame.setlayout(layout); frame.add(titlepanel); frame.add(extractpoibutton); frame.add(clearpoibutton); layout.putconstraint(springlayout.west, titlepanel, 10, SpringLayout.WEST, layout.putconstraint(springlayout.north, titlepanel, 10, SpringLayout.NORTH, layout.putconstraint(springlayout.east, titlepanel, 10, SpringLayout.EAST, layout.putconstraint(springlayout.west, extractpoibutton, 10, SpringLayout.WEST, layout.putconstraint(springlayout.north, extractpoibutton, 10, SpringLayout.SOUTH, titlepanel); layout.putconstraint(springlayout.west, clearpoibutton, 10, SpringLayout.EAST, extractpoibutton); layout.putconstraint(springlayout.north, clearpoibutton, 10, SpringLayout.SOUTH, titlepanel); //layout.putconstraint(springlayout.east, clearpoibutton, 10, SpringLayout.EAST, frame.setsize(300, 300); public void actionperformed(actionevent ae) { if (ae.getsource()== extractpoibutton) { double [] center = spsi.getcenter(); System.out.println("Center: " + center[0] + ", " + center[1]); processlocation(center[0], center[1], 1000); else if (ae.getsource() == clearpoibutton) { spsi.clearlayer(layername); public void addmarker(double latitude, double longitude, String description) { GenericMapMarker currentposition = spsi.createmapmarker(description); currentposition.setlat(latitude); currentposition.setlon(longitude); spsi.addmarkertolayer(layername, currentposition); Page 5 of 8

6 public void processlocation(double latitude, double longitude, int radius) { String urlstr = " + radius + "&gscoord=" + latitude + " " + longitude; try { URL url = new URL(urlStr); InputStream is = url.openstream(); JsonReader rdr = Json.createReader(is); JsonObject obj = rdr.readobject(); JsonObject queryobj = obj.getjsonobject("query"); //System.out.println(queryObj.toString()); JsonArray geosearcharray = queryobj.getjsonarray("geosearch"); //System.out.println(geosearchArray.toString()); /* for (Object o:geosearcharray) { System.out.println(o.toString()); */ for (int i = 0; i<geosearcharray.size(); i++) { System.out.print(i + ": "); JsonObject poi = geosearcharray.getjsonobject(i); String title = poi.getstring("title"); System.out.print(title + ", "); JsonNumber latnum = poi.getjsonnumber("lat"); System.out.print(latNum + " by "); JsonNumber lonnum = poi.getjsonnumber("lon"); System.out.println(lonNum); addmarker(latnum.doublevalue(), lonnum.doublevalue(), title); catch (MalformedURLException murle) { catch (IOException ioe) { public PluginData getplugindata() { PluginData pd = new PluginData(this.getClass().getCanonicalName(), description, "created"); Page 6 of 8

7 pd.setspatialplugininstance(this); return pd; public String getvendor() { return vendor; public SpatialPluginVersion getversion() { return version; public void active(boolean status) { pluginstatus = status; public boolean isactive() { return pluginstatus; public void setvisible(boolean status) { frame.setvisible(status); public boolean isvisible() { return frame.isvisible(); public void setsize(int width, int height) { frame.setsize(width, height); public int getwidth() { return frame.getwidth(); public int getheight() { return frame.getheight(); public void setspatialpluginserviceimplementation(spatialpluginserviceimplementation spsi) { this.spsi = spsi; // create gps marker and layer to display it on the map //currentposition = spsi.createmapmarker("current Position"); spsi.addlayer(layername); Page 7 of 8

8 Listing 2: config.xml exhibits the configuration requirements to load the Wikipedia plug-in. It should be noted that the Wikipedia plug-in is dependent on java.json jar library. <plugins> <plugin> <name>wikipedia Extractor</name> <comment>wikipedia Point of Interest Extraction Utility</comment> <jar-file>plugin/wikipedia/wikipediaplugin.jar</jar-file> <libs>plugin/ztassetmon/javax.json jar</libs> <class-file>com.zerotrak.plugin.examples.wikipediaplugin</class-file> </plugin> <! --> Load as many plugins as it is required by a user by using <plugin> tags </plugins> Deploying a Plug-in Once a plug-in has been created, compiled and packaged into a jar file it may be used by PlaniSphere. The WikipediaExtractor contains a jar file named WikipediaPlugin.jar that contains only one file named WikipediaPlugin.class. Plug-ins are loaded automatically when PlaniSphere starts. PlaniSphere will use the config.xml to load all plug-ins. A plug-is housed in a jar file. PlaniSphere will load a jar file specified in the jar-file tag. Listing 1 exhibits a plug-in named WikipediaExtractor. Its jar file is WikipediaPlugin.jar. The WikipediaExtractor may be started by creating an instance of the class found in the class-file tag. In this case it is com.zerotrak.plugin.example.wikipediaplugin. The WikipediaExtractor requires dependent libraries in order to function. These dependent libraries may be found in the libs tag. Once a plug-in has been loaded by PlaniSphere (at startup) it will become available for usage through the Plug-in Manager. Figure 2 shows PlaniSphere and the Plug-in Manager successfully loading multiple plugins. Page 8 of 8