GoogleMapsGeocoder.java

package cas2xb3.greenlight;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.nio.charset.Charset;
import org.json.*;

/**
 * 
 * This class is used to geocode a location. It allows us to retrieve the coordinates of an input location, like the coordinates of Toronto Ontario.
 * This class makes use of several files located in the org.json package. The code located in the org.json package was retrieved from https://github.com/stleary/JSON-java.
 * The methods contained within this class reads from a JSON output and retrieves the coordinates of a location. It includes methods which return the coordinates, along with
 * the latitude and longitude independently. 
 *
 */
public class GoogleMapsGeocoder {

	private static JSONObject json;

	private static double longitude;

	private static double latitude;

	private static String lng;

	private static String lat;

	private static String ReplacementAddress;

	/**
	 * This method reads the content of a file and transitions the contents into a string.
	 * The framework for this piece of code was referred from http://stackoverflow.com/a/4308662/7454970. 
	 * 
	 * @param br - This represents a BufferedReader that reads the content of a file.
	 * @return This method returns a string holding all the contents of a file.
	 * @throws IOException
	 */
	private static String readAll(BufferedReader br) throws IOException {
		StringBuilder contents = new StringBuilder();
		int i;
		
		// Moving the contents which is being read into the string builder.
		
		while ((i = br.read()) != -1) {
			contents.append((char) i);
		}
		
		// Returning the string with all the contents from the file.
		return contents.toString();
	}

	/**
	 * This method reads JSON code from a url. It moves the contents from the url into a string, and then moves the string into a JSONObject.
	 * The JSONObject is then returned.
	 * The framework for this piece of code was referred from http://stackoverflow.com/a/4308662/7454970. 
	 * 
	 * @param url - This parameter represents a url which contains JSON code.
	 * @return This method returns a JSONObject containing all the JSON code retrieved from the url.
	 * @throws IOException
	 * @throws JSONException
	 */
	public static JSONObject readJsonFromUrl(String url) throws IOException, JSONException {
		InputStream is = new URL(url).openStream();
		try {
			
			// Reading the contents from a url, moving it to a string, and then into a JSONObject
			BufferedReader br = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
			String jsonText = readAll(br);
			JSONObject json = new JSONObject(jsonText);
			return json;
		} finally {
			is.close();
		}

	}

	/**
	 * This method is used to retrieve the latitude and longitude of an input address from a url generated by the Google Maps Geocoding API. 
	 * It then returns a string which includes the coordinates of the location.
	 * This method made use of the Google Maps Geocoding API, primarily the url, at https://developers.google.com/maps/documentation/geocoding/intro.
	 * 
	 * @param address - This represents an address which is to be geocoded. 
	 * @return A string of form latitude , longnitude is returned, containing the coordinates of an object.
	 * @throws JSONException
	 * @throws IOException
	 */
	public static String getCoordinates(String address) throws JSONException, IOException {

		// Spaces cause errors with the url, if the input contains spaces they will be removed.
		if (address.contains(" ")) {

			for (int i = 0; i < address.length(); i++) {

				ReplacementAddress = address.replace(" ", "");

			}

			json = readJsonFromUrl("https://maps.googleapis.com/maps/api/geocode/json?address=" + ReplacementAddress
					+ "&key=AIzaSyAgOPBEIzwBTQmWbZHHApZfqi8sEbSmKy8");

		} else {

			json = readJsonFromUrl("https://maps.googleapis.com/maps/api/geocode/json?address=" + address
					+ "&key=AIzaSyAgOPBEIzwBTQmWbZHHApZfqi8sEbSmKy8");

		}
		
		String name = json.getJSONArray("results").toString();

		// Splitting the string with the JSON output in order to isolate the coordinates.
		String[] test = name.split(",|}|:");

		// Extracting the coordinates by searching for where they are located
		for (int i = 0; i < test.length; i++) {

			if (test[i].equals('"' + "location" + '"')) {

				// Longitude is located 2 indexes away from "location"
				lng = test[i + 2];

				// Latitude is located 4 indexes away from "location"
				lat = test[i + 4];

			}

		}

		// Parsing the coordinates into a double so it could be used properly in other classes.
		longitude = Double.parseDouble(lng);

		latitude = Double.parseDouble(lat);

		return (getLatitude() + " , " + getlongitude());

	}

	/**
	 * This method acts as a getter for the latitude.
	 * 
	 * @return The latitude of a location is returned.
	 */
	public static double getLatitude() {

		return latitude;

	}

	/**
	 * This method acts as a getter for the longitude.
	 * 
	 * @return The longitude of a location is returned.
	 */
	public static double getlongitude() {

		return longitude;

	}

}