Beispiel #1
0
  /**
   * Instantiates the query for rscore
   *
   * @param query contains user query
   * @param cmp contains compare structure
   * @param resultIndices passes the indices that store the result
   * @throws DatabaseException when BerkeleyDB passes errors
   * @throws FileNotFoundException when respective .idx or .txt value not found
   */
  private void queryRScore(String query, ArrayList<Integer> resultIndices, COMPARE cmp)
      throws FileNotFoundException, DatabaseException {
    if (cmp == COMPARE.EQUAL) {
      query = query.replace("rscore=", "").toLowerCase();
      queryDB(query, rscoreIndex, resultIndices);
      return;
    } else if (cmp == COMPARE.LESS) {
      query = query.replace("rscore<", "");
    } else {
      query = query.replace("rscore>", "");
    }

    OperationStatus oprStatus;
    Database std_db = new Database(rscoreIndex, null, null);
    Cursor std_cursor = std_db.openCursor(null, null); // Create new cursor object

    if (cmp == COMPARE.LESS) {
      for (int n = 0; n < Integer.parseInt(query); n++) {
        String searchkey = new String();
        searchkey = n + ".0";
        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry data = new DatabaseEntry();
        oprStatus = std_cursor.getFirst(key, data, LockMode.DEFAULT);
        key.setData(searchkey.getBytes());
        key.setSize(searchkey.length());
        data = new DatabaseEntry();
        oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
        while (oprStatus == OperationStatus.SUCCESS) {
          String s = new String(data.getData());
          if (!(resultIndices.contains(Integer.parseInt(s)))) {
            resultIndices.add(Integer.parseInt(s));
          }
          oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
        }
      }

    } else {
      for (int n = 5; n > Integer.parseInt(query); n--) {
        String searchkey = new String();
        searchkey = n + ".0";
        DatabaseEntry key = new DatabaseEntry();
        DatabaseEntry data = new DatabaseEntry();
        oprStatus = std_cursor.getFirst(key, data, LockMode.DEFAULT);
        key.setData(searchkey.getBytes());
        key.setSize(searchkey.length());
        data = new DatabaseEntry();
        oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
        while (oprStatus == OperationStatus.SUCCESS) {
          String s = new String(data.getData());
          if (!(resultIndices.contains(Integer.parseInt(s)))) {
            resultIndices.add(Integer.parseInt(s));
          }
          oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
        }
      }
    }
  }
Beispiel #2
0
  public static Database buildsecondary(Database std) {
    // Parse database loaded
    try {
      io.deleteFile("secondarydb");
      // SecondaryDatabases started
      DatabaseConfig dbConfig = new DatabaseConfig();
      dbConfig.setType(DatabaseType.HASH);
      dbConfig.setAllowCreate(true);
      dbConfig.setUnsortedDuplicates(true);
      Database secdb = new Database("secondarydb", null, dbConfig);
      // Cursors started
      Cursor stdcursor = std.openCursor(null, null);
      Cursor secdbcursor = secdb.openCursor(null, null);
      // Key and Data started
      DatabaseEntry stdkey = new DatabaseEntry();
      DatabaseEntry stddata = new DatabaseEntry();
      DatabaseEntry seckey = new DatabaseEntry();
      DatabaseEntry secdata = new DatabaseEntry();

      while (stdcursor.getNext(stdkey, stddata, LockMode.DEFAULT)
          == OperationStatus.SUCCESS) { // Writing into secondary db
        String[] key = new String(stdkey.getData()).split(",");
        String data = new String(stddata.getData());
        // DEBUG:
        // System.out.println("key 0:" + key[0] + " key 1:" + key[1] + " data:" + data);
        seckey.setData(key[1].getBytes());
        OperationStatus operation = secdbcursor.getSearchKey(seckey, secdata, LockMode.DEFAULT);

        String b = null;
        while (operation == OperationStatus.SUCCESS) {
          b = new String(secdata.getData());
          secdbcursor.delete();
          operation = secdbcursor.getNextDup(seckey, secdata, LockMode.DEFAULT);
        }
        if (b == null) {
          seckey.setData(key[1].getBytes());
          secdata.setData(("(" + key[0] + "," + data + ")").getBytes());
          secdb.put(null, seckey, secdata);
        }
        if (b != null) {
          secdata.setData(b.concat("(" + key[0] + "," + data + ")").getBytes());
          secdb.put(null, seckey, secdata);
        }
        seckey.setData(null);
        secdata.setData(null);

        stdkey.setData(null);
        stddata.setData(null);
      }
      // io.debugread(secdb);

      return secdb;
    } catch (Exception e) {
      System.out.println("Error creating <user>,<song,rating> secondary table!\n");
      System.out.println(e.getMessage());
    }
    return null; // SHOULD NEVER HAPPEN
  }
Beispiel #3
0
  /**
   * Generic query process
   *
   * @param query contains parsed query for process
   * @param db_name contains database to query
   * @param indices passes the indices that store the result
   * @throws DatabaseException when BerkeleyDB passes errors
   * @throws FileNotFoundException when respective .idx or .txt value not found
   */
  private void queryDB(String query, String db_name, ArrayList<Integer> indices)
      throws DatabaseException, FileNotFoundException {
    OperationStatus oprStatus;
    Database std_db = new Database(db_name, null, null);
    Cursor std_cursor = std_db.openCursor(null, null); // Create new cursor object
    DatabaseEntry key = new DatabaseEntry();
    DatabaseEntry data = new DatabaseEntry();

    key.setData(query.getBytes());
    key.setSize(query.length());

    // Returns OperationStatus
    oprStatus = std_cursor.getSearchKey(key, data, LockMode.DEFAULT);
    while (oprStatus == OperationStatus.SUCCESS) {
      String s = new String(data.getData());
      if (!(indices.contains(Integer.parseInt(s)))) {
        indices.add(Integer.parseInt(s));
      }
      oprStatus = std_cursor.getNextDup(key, data, LockMode.DEFAULT);
    }

    std_cursor.close();
    std_db.close();
  }