Android Open Source - tum-campus Transport Manager

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License

The source code is released under:

GNU General Public License

Java Source Code

?package de.tum.in.tumcampus.models;
//from  w w  w. j av  a  2 s.  c om
import java.net.URLEncoder;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import de.tum.in.tumcampus.common.Utils;

import android.content.Context;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.database.sqlite.SQLiteDatabase;

/**
 * Transport Manager, handles database stuff, internet connections
 */
public class TransportManager {

  /**
   * Database connection
   */
  private SQLiteDatabase db;

  /**
   * Constructor, open/create database, create table if necessary
   * 
   * <pre>
   * @param context Context
   * </pre>
   */
  public TransportManager(Context context) {
    db = DatabaseManager.getDb(context);

    // create table if needed
    db.execSQL("CREATE TABLE IF NOT EXISTS transports (name VARCHAR PRIMARY KEY)");
  }

  /**
   * Get all departures for a station
   * 
   * Cursor includes target station name, departure in remaining minutes
   * 
   * <pre>
   * @param location Station name
   * @return Database cursor (name, desc, _id)
   * @throws Exception
   * </pre>
   */
  public Cursor getDeparturesFromExternal(String location) throws Exception {
    String baseUrl = "http://query.yahooapis.com/v1/public/yql?format=json&q=";

    // ISO needed for mvv
    String lookupUrl = "http://www.mvg-live.de/ims/dfiStaticAnzeige.svc?haltestelle="
        + URLEncoder.encode(location, "ISO-8859-1");

    String query = URLEncoder.encode("select content from html where url=\"" + lookupUrl
        + "\" and xpath=\"//td[contains(@class,'Column')]/p\"");
    Utils.log(query);

    JSONArray jsonArray = Utils.downloadJson(baseUrl + query).getJSONObject("query").getJSONObject("results")
        .getJSONArray("p");

    if (jsonArray.length() < 3) {
      throw new Exception("<Keine Abfahrten gefunden>");
    }

    MatrixCursor mc = new MatrixCursor(new String[] { "name", "desc", "_id" });

    for (int j = 2; j < jsonArray.length(); j = j + 3) {
      String name = jsonArray.getString(j) + " " + jsonArray.getString(j + 1).trim();

      String desc = jsonArray.getString(j + 2) + " min";

      mc.addRow(new String[] { name, desc, String.valueOf(j) });
    }
    return mc;
  }

  /**
   * Find stations by station name prefix
   * 
   * <pre>
   * @param location Name prefix
   * @return Database Cursor (name, _id)
   * @throws Exception
   * </pre>
   */
  public Cursor getStationsFromExternal(String location) throws Exception {

    String baseUrl = "http://query.yahooapis.com/v1/public/yql?format=json&q=";

    String lookupUrl = "http://www.mvg-live.de/ims/dfiStaticAuswahl.svc?haltestelle="
        + URLEncoder.encode(location, "ISO-8859-1");

    String query = URLEncoder.encode("select content from html where url=\"" + lookupUrl
        + "\" and xpath=\"//a[contains(@href,'haltestelle')]\"");
    Utils.log(query);

    JSONObject jsonObj = Utils.downloadJson(baseUrl + query).getJSONObject("query");

    JSONArray jsonArray = new JSONArray();
    try {
      Object obj = jsonObj.getJSONObject("results").get("a");
      if (obj instanceof JSONArray) {
        jsonArray = (JSONArray) obj;
      } else {
        if (obj.toString().contains("aktualisieren")) {
          throw new JSONException("");
        }
        jsonArray.put(obj);
      }
    } catch (JSONException e) {
      throw new Exception("<Keine Station(en) gefunden>");
    }

    MatrixCursor mc = new MatrixCursor(new String[] { "name", "_id" });

    for (int j = 0; j < jsonArray.length(); j++) {
      String station = jsonArray.getString(j).replaceAll("\\s+", " ");

      mc.addRow(new String[] { station, String.valueOf(j) });
    }
    return mc;
  }

  /**
   * Get all stations from the database
   * 
   * @return Database cursor (name, _id)
   */
  public Cursor getAllFromDb() {
    return db.rawQuery("SELECT name, name as _id FROM transports ORDER BY name", null);
  }

  /**
   * Checks if the transports table is empty
   * 
   * @return true if no stations are available, else false
   */
  public boolean empty() {
    boolean result = true;
    Cursor c = db.rawQuery("SELECT name FROM transports LIMIT 1", null);
    if (c.moveToNext()) {
      result = false;
    }
    c.close();
    return result;
  }

  /**
   * Replace or Insert a station into the database
   * 
   * <pre>
   * @param name Station name
   * @throws Exception
   * </pre>
   */
  public void replaceIntoDb(String name) {
    Utils.log(name);

    if (name.length() == 0) {
      return;
    }
    db.execSQL("REPLACE INTO transports (name) VALUES (?)", new String[] { name });
  }

  /**
   * delete a station from the database
   * 
   * <pre>
   * @param name Station name
   * </pre>
   */
  public void deleteFromDb(String name) {
    db.execSQL("DELETE FROM transports WHERE name = ?", new String[] { name });
  }
}

Java Source Code List

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