KML.java

package com.aerodynelabs.map;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.ListIterator;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

/**
 * A class to represent, write, and read KML files.
 * 
 * @author Ethan Harstad
 *
 */
public class KML {
	
	private Document doc;
	private Element root;
	
	/**
	 * Create a KML object.
	 */
	public KML() {
		try {
			DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = factory.newDocumentBuilder();
			doc = builder.newDocument();
			Element kml = doc.createElementNS("http://www.opengis.net/kml/2.2", "kml");
			doc.appendChild(kml);
			root = doc.createElement("Document");
			kml.appendChild(root);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * Add a placemark to this KML object.
	 * @param mark
	 */
	public void addMark(MapPoint mark) {
		Element placemark = doc.createElement("Placemark");
		root.appendChild(placemark);
		
		Element name = doc.createElement("name");
		name.appendChild(doc.createTextNode(mark.getName()));
		placemark.appendChild(name);
		
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
		Element desc = doc.createElement("description");
		desc.appendChild(doc.createTextNode(mark.getLatitude() + ", " + mark.getLongitude() + "\n" +
				"Altitude: " + mark.getAltitude() + " meters\n" +
				"Time: " + sdf.format(new Date(mark.getTime()))));
		placemark.appendChild(desc);
		
		Element point = doc.createElement("Point");
		placemark.appendChild(point);
		
		if(mark.getAltitude() > 0) {
			Element altitudeMode = doc.createElement("altitudeMode");
			altitudeMode.appendChild(doc.createTextNode("absolute"));
			point.appendChild(altitudeMode);
		}
		
		Element coords = doc.createElement("coordinates");
		coords.appendChild(doc.createTextNode(mark.getLongitude() + ", " + mark.getLatitude() + ", " + mark.getAltitude()));
		point.appendChild(coords);
	}
	
	/**
	 * Add a path to this KML object.
	 * @param path
	 * @param pathName
	 */
	public void addPath(List<MapPoint> path, String pathName) {
		Element placemark = doc.createElement("Placemark");
		root.appendChild(placemark);
		
		if(pathName != null) {
			Element name = doc.createElement("name");
			name.appendChild(doc.createTextNode(pathName));
			placemark.appendChild(name);
		}
		
		Element lineString = doc.createElement("LineString");
		placemark.appendChild(lineString);
		
		Element extrude = doc.createElement("extrude");
		extrude.appendChild(doc.createTextNode("1"));
		lineString.appendChild(extrude);
		
		Element tesselate = doc.createElement("tesselate");
		tesselate.appendChild(doc.createTextNode("1"));
		lineString.appendChild(tesselate);
		
		Element altitudeMode = doc.createElement("altitudeMode");
		altitudeMode.appendChild(doc.createTextNode("absolute"));
		lineString.appendChild(altitudeMode);
		
		Element coords = doc.createElement("coordinates");
		String points = "";
		ListIterator<MapPoint> itr = path.listIterator();
		while(itr.hasNext()) {
			MapPoint p = itr.next();
			points += p.getLongitude() + "," + p.getLatitude() + "," + p.getAltitude() + "\n";
		}
		coords.appendChild(doc.createTextNode(points));
		lineString.appendChild(coords);
	}
	
	/**
	 * Write this KML object to a file.
	 * @param file
	 * @return
	 */
	public boolean writeFile(File file) {
		try {
			TransformerFactory factory = TransformerFactory.newInstance();
			Transformer transformer = factory.newTransformer();
			transformer.setOutputProperty(OutputKeys.INDENT, "yes");
			transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
			DOMSource src = new DOMSource(doc);
			StreamResult out = new StreamResult(file);
			transformer.transform(src, out);
		} catch(Exception e) {
			e.printStackTrace();
			return false;
		}
		return true;
	}
	
	/**
	 * Read the KML file into this object.
	 * @param file
	 */
	public void readFile(File file) {
		// TODO read KML file
	}

}