Android Open Source - tum-campus Cafeteria Menu 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;
//  w ww.j av a  2 s . c o  m
import static de.tum.in.tumcampus.common.Utils.getDate;

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

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

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

/**
 * Cafeteria Menu Manager, handles database stuff, external imports
 */
public class CafeteriaMenuManager {

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

  /**
   * Last insert counter
   */
  public static int lastInserted = 0;

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

    // create table if needed
    db.execSQL("CREATE TABLE IF NOT EXISTS cafeterias_menus ("
        + "id INTEGER, mensaId INTEGER KEY, date VARCHAR, typeShort VARCHAR, "
        + "typeLong VARCHAR, typeNr INTEGER, name VARCHAR)");
  }

  /**
   * Download cafeteria menus from external interface (JSON)
   * 
   * <pre>
   * @param ids List of cafeteria IDs to download items for
   * @param force True to force download over normal sync period, else false
   * @throws Exception
   * </pre>
   */
  public void downloadFromExternal(boolean force) throws Exception {

    if (!force && !SyncManager.needSync(db, this, 86400)) {
      return;
    }
    cleanupDb();
    int count = Utils.dbGetTableCount(db, "cafeterias_menus");

    Cursor c = db.rawQuery("SELECT 1 FROM cafeterias_menus WHERE date > date('now', '+6 day') LIMIT 1", null);
    if (c.getCount() > 0) {
      c.close();
      return;
    }
    c.close();

    String url = "http://lu32kap.typo3.lrz.de/mensaapp/exportDB.php?mensa_id=all";
    JSONObject json = Utils.downloadJson(url);

    removeCache();
    db.beginTransaction();
    try {
      JSONArray menu = json.getJSONArray("mensa_menu");
      for (int j = 0; j < menu.length(); j++) {
        replaceIntoDb(getFromJson(menu.getJSONObject(j)));
      }

      JSONArray beilagen = json.getJSONArray("mensa_beilagen");
      for (int j = 0; j < beilagen.length(); j++) {
        replaceIntoDb(getFromJsonAddendum(beilagen.getJSONObject(j)));
      }
      db.setTransactionSuccessful();
    } finally {
      db.endTransaction();
    }
    SyncManager.replaceIntoDb(db, this);

    // update last insert counter
    lastInserted += Utils.dbGetTableCount(db, "cafeterias_menus") - count;
  }

  /**
   * Get all distinct menu dates from the database
   * 
   * @return Database cursor (date_de, _id)
   */
  public Cursor getDatesFromDb() {
    return db.rawQuery("SELECT DISTINCT strftime('%d.%m.%Y', date) as date_de, date as _id "
        + "FROM cafeterias_menus WHERE date >= date() ORDER BY date", null);
  }

  /**
   * Get all types and names from the database for a special date and a special cafeteria
   * 
   * <pre>
   * @param mensaId Mensa ID, e.g. 411
   * @param date ISO-Date, e.g. 2011-12-31 
   * @return Database cursor (typeLong, names, _id)
   * </pre>
   */
  public Cursor getTypeNameFromDb(String mensaId, String date) {
    return db.rawQuery("SELECT typeLong, group_concat(name, '\n') as names, id as _id "
        + "FROM cafeterias_menus WHERE mensaId = ? AND "
        + "date = ? GROUP BY typeLong ORDER BY typeNr, typeLong, name", new String[] { mensaId, date });
  }

  /**
   * Convert JSON object to CafeteriaMenu
   * 
   * Example JSON: e.g. {"id":"25544","mensa_id":"411","date":"2011-06-20","type_short" :"tg","type_long":"Tagesgericht 3","type_nr":"3","name":
   * "Cordon bleu vom Schwein (mit Formfleischhinterschinken) (S) (1,2,3,8)"}
   * 
   * <pre>
   * @param json see above
   * @return CafeteriaMenu
   * @throws Exception
   * </pre>
   */
  public static CafeteriaMenu getFromJson(JSONObject json) throws Exception {

    return new CafeteriaMenu(json.getInt("id"), json.getInt("mensa_id"), Utils.getDate(json.getString("date")),
        json.getString("type_short"), json.getString("type_long"), json.getInt("type_nr"),
        json.getString("name"));
  }

  /**
   * Convert JSON object to CafeteriaMenu (addendum)
   * 
   * Example JSON: e.g. {"mensa_id":"411","date":"2011-07-29","name":"Pflaumenkompott" ,"type_short":"bei","type_long":"Beilagen"}
   * 
   * <pre>
   * @param json see above
   * @return CafeteriaMenu
   * @throws Exception
   * </pre>
   */
  public static CafeteriaMenu getFromJsonAddendum(JSONObject json) throws Exception {

    return new CafeteriaMenu(0, json.getInt("mensa_id"), Utils.getDate(json.getString("date")),
        json.getString("type_short"), json.getString("type_long"), 10, json.getString("name"));
  }

  /**
   * Replace or Insert a cafeteria menu in the database
   * 
   * <pre>
   * @param c CafeteriaMenu object
   * @throws Exception
   * </pre>
   */
  public void replaceIntoDb(CafeteriaMenu c) throws Exception {
    if (c.cafeteriaId <= 0) {
      throw new Exception("Invalid cafeteriaId.");
    }
    if (c.name.length() == 0) {
      throw new Exception("Invalid name.");
    }
    if (c.typeLong.length() == 0) {
      throw new Exception("Invalid typeLong.");
    }
    if (c.typeShort.length() == 0) {
      throw new Exception("Invalid typeShort.");
    }
    if (c.date.before(getDate("2011-01-01"))) {
      throw new Exception("Invalid date.");
    }
    db.execSQL("REPLACE INTO cafeterias_menus (id, mensaId, date, typeShort, "
        + "typeLong, typeNr, name) VALUES (?, ?, ?, ?, ?, ?, ?)",
        new String[] { String.valueOf(c.id), String.valueOf(c.cafeteriaId), Utils.getDateString(c.date),
            c.typeShort, c.typeLong, String.valueOf(c.typeNr), c.name });
  }

  /**
   * Removes all cache items
   */
  public void removeCache() {
    db.execSQL("DELETE FROM cafeterias_menus");
  }

  /**
   * Removes all old items (older than 7 days)
   */
  public void cleanupDb() {
    db.execSQL("DELETE FROM cafeterias_menus WHERE date < date('now','-7 day')");
  }
}

Java Source Code List

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