Java tutorial
// Copyright (c) 2010 Martin Atkins. All rights reserved. // Use of this source code is governed by a BSD-style license that can // be found in the LICENSE file. /* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */ package org.neugierig.proximo; import android.os.Parcel; import android.os.Parcelable; import java.net.*; import java.io.*; import org.json.*; class ProximoBus { private static final String API_URL = "http://proximobus.appspot.com/agencies/sf-muni/"; public static class Displayable { public String displayName; public String toString() { return displayName; } } public static class Route extends Displayable { static final String RUNS_PATH_FORMAT = "routes/%s/runs.json"; public String id; public static Route fromJsonObject(JSONObject obj) throws JSONException { Route route = new Route(); route.displayName = obj.getString("display_name"); route.id = obj.getString("id"); return route; } } public static class Run extends Displayable { static final String STOPS_PATH_FORMAT = "routes/%s/runs/%s/stops.json"; public String id; public String routeId; public boolean displayInUi; public static Run fromJsonObject(JSONObject obj) throws JSONException { Run run = new Run(); run.displayName = obj.getString("display_name"); run.id = obj.getString("id"); run.routeId = obj.getString("route_id"); run.displayInUi = obj.getBoolean("display_in_ui"); return run; } } public static class Stop extends Displayable { static final String PREDICTIONS_PATH_FORMAT = "stops/%s/predictions.json"; static final String PREDICTIONS_BY_ROUTE_PATH_FORMAT = "stops/%s/predictions/by-route/%s.json"; public String id; public static Stop fromJsonObject(JSONObject obj) throws JSONException { Stop stop = new Stop(); stop.displayName = obj.getString("display_name"); stop.id = obj.getString("id"); return stop; } } public static class Prediction implements Parcelable { public String routeId; public String runId; public int minutes; public boolean isDeparting; public static Prediction fromJsonObject(JSONObject obj) throws JSONException { Prediction prediction = new Prediction(); prediction.routeId = obj.getString("route_id"); prediction.runId = obj.getString("run_id"); prediction.minutes = obj.getInt("minutes"); prediction.isDeparting = obj.getBoolean("is_departing"); return prediction; } public String toString() { if (minutes == 0) { if (isDeparting) { return "Departing"; } else { return "Arriving"; } } else { if (minutes == 1) { return "1 minute"; } else { return minutes + " minutes"; } } } public Prediction() { } public Prediction(Parcel in) { routeId = in.readString(); runId = in.readString(); minutes = in.readInt(); isDeparting = in.readInt() != 0; } @Override public int describeContents() { return 0; // No special Parcelable info. } @Override public void writeToParcel(Parcel out, int flags) { out.writeString(routeId); out.writeString(runId); out.writeInt(minutes); out.writeInt(isDeparting ? 1 : 0); } public static final Parcelable.Creator<Prediction> CREATOR = new Parcelable.Creator<Prediction>() { @Override public Prediction createFromParcel(Parcel in) { return new Prediction(in); } @Override public Prediction[] newArray(int size) { return new Prediction[size]; } }; } static String getAllRoutesPath() { return "routes.json"; } static String getRunsOnRoutePath(String routeId) { // FIXME: URLEncode.encode turns " " into "+", but ProximoBus expects "%20". // this means that we can't currently support Owl routes, which have ids like "N OWL". return String.format(Route.RUNS_PATH_FORMAT, URLEncoder.encode(routeId)); } static String getStopsOnRunPath(String routeId, String runId) { return String.format(Run.STOPS_PATH_FORMAT, URLEncoder.encode(routeId), runId); } static String getStopPredictionsByRoutePath(String stopId, String routeId) { return String.format(Stop.PREDICTIONS_BY_ROUTE_PATH_FORMAT, stopId, URLEncoder.encode(routeId)); } static Route[] parseRoutes(String data) throws JSONException { JSONObject res = new JSONObject(data); JSONArray array = res.getJSONArray("items"); Route[] routes = new Route[array.length()]; for (int i = 0; i < array.length(); ++i) { JSONObject entry = array.getJSONObject(i); routes[i] = Route.fromJsonObject(entry); } return routes; } static Run[] parseRuns(String data) throws JSONException { JSONObject res = new JSONObject(data); JSONArray array = res.getJSONArray("items"); // This assumes that there are only ever two displayInUi runs. // This seems to be true for all of the Muni routes I've looked at, // but if it turns out that some have three or more we'll need to // revisit this. Run[] runs = new Run[2]; int runIndex = 0; for (int i = 0; i < array.length(); ++i) { JSONObject entry = array.getJSONObject(i); Run run = Run.fromJsonObject(entry); if (run.displayInUi) { runs[runIndex++] = Run.fromJsonObject(entry); if (runIndex > 1) break; } } return runs; } static Stop[] parseStops(String data) throws JSONException { JSONObject res = new JSONObject(data); JSONArray array = res.getJSONArray("items"); Stop[] stops = new Stop[array.length()]; for (int i = 0; i < array.length(); ++i) { JSONObject entry = array.getJSONObject(i); stops[i] = Stop.fromJsonObject(entry); } return stops; } static Prediction[] parsePredictions(String data) throws JSONException { JSONObject res = new JSONObject(data); JSONArray array = res.getJSONArray("items"); Prediction[] predictions = new Prediction[array.length()]; for (int i = 0; i < array.length(); ++i) { JSONObject entry = array.getJSONObject(i); predictions[i] = Prediction.fromJsonObject(entry); } return predictions; } static String queryNetwork(String path) throws MalformedURLException, IOException { return fetchURL(new URL(API_URL + path)); } // It's pretty unbelievable there's no simpler way to do this. static String fetchURL(URL url) throws IOException { InputStream input = url.openStream(); StringBuffer buffer = new StringBuffer(8 << 10); int byte_read; while ((byte_read = input.read()) != -1) { // This is incorrect for non-ASCII, but we don't have any of that. buffer.appendCodePoint(byte_read); } return buffer.toString(); } }