feat: add City class to store city and fetch its coordinates

src/main/java/eirb/pg203/city.java

@@ -0,0 +1,97 @@
+package eirb.pg203;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URL;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+import eirb.pg203.utils.Coords;
+
+class City {
+	private String cityName;
+	private Coords cityCoords;
+
+	/**
+	 * Fetch data from adresse.data.gouv.fr
+	 * @throws IOException if the request fails
+	 */
+	private static JSONObject getDataFromName(String cityName) throws IOException {
+		StringBuilder result = new StringBuilder();
+		URL url = URI.create(
+			String.format("https://api-adresse.data.gouv.fr/search/?q=%s&autocomplete=0&limit=1",
+				cityName
+			)
+		).toURL();
+
+		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+		conn.setRequestMethod("GET");
+
+		try (BufferedReader reader = new BufferedReader(
+				new InputStreamReader(conn.getInputStream()))) {
+			for (String line; (line = reader.readLine()) != null; ) {
+				result.append(line);
+			}
+		}
+
+		return new JSONObject(result.toString());
+	}
+
+	private static Coords getCoordsFromName(String cityName) throws IOException {
+		JSONObject data = getDataFromName(cityName);
+		JSONArray rawCoords = data.getJSONArray("features")
+			.getJSONObject(0)
+			.getJSONObject("geometry")
+			.getJSONArray("coordinates");
+
+		final float lon = rawCoords.getFloat(0);
+		final float lat = rawCoords.getFloat(1);
+
+		return new Coords(lat, lon);
+	}
+
+	City (String cityName) {
+		this.cityName = cityName;
+	}
+
+	public String getCityName() {
+		return cityName;
+	}
+
+	/**
+	 * Returns the city coords using adresse.data.gouv.fr, cache the result
+	 * @return the city Coords
+	 * @throws IOException if the request to adresse.data.gouv.fr fails
+	 *
+	 */
+	public Coords getCityCoords() throws IOException {
+		if (this.cityCoords == null) {
+			this.cityCoords = getCoordsFromName(cityName);
+		}
+
+		return cityCoords;
+	}
+
+	@Override
+	public String toString() {
+		try {
+			Coords coords = this.getCityCoords();
+			return String.format(
+					"City(%s, lat: %f, lon: %f)",
+					this.cityName,
+					coords.getLat(),
+					coords.getLon()
+				);
+		}
+		catch (IOException e) {
+			return String.format(
+					"City(%s, lat: Request failed, lon: Request Failed)",
+					this.cityName
+				);
+		}
+	}
+}