Ejemplo n.º 1
0
  /**
   * constructor
   *
   * @param file_name heapfile to be opened
   * @param in1[] array showing what the attributes of the input fields are.
   * @param s1_sizes[] shows the length of the string fields.
   * @param len_in1 number of attributes in the input tuple
   * @param n_out_flds number of fields in the out tuple
   * @param proj_list shows what input fields go where in the output tuple
   * @param outFilter select expressions
   * @exception IOException some I/O fault
   * @exception FileScanException exception from this class
   * @exception TupleUtilsException exception from this class
   * @exception InvalidRelation invalid relation
   */
  public FileScan(
      String file_name,
      AttrType in1[],
      short s1_sizes[],
      short len_in1,
      int n_out_flds,
      FldSpec[] proj_list,
      CondExpr[] outFilter)
      throws IOException, FileScanException, TupleUtilsException, InvalidRelation {
    _in1 = in1;
    in1_len = len_in1;
    s_sizes = s1_sizes;

    Jtuple = new Tuple();
    AttrType[] Jtypes = new AttrType[n_out_flds];
    short[] ts_size;
    ts_size =
        TupleUtils.setup_op_tuple(Jtuple, Jtypes, in1, len_in1, s1_sizes, proj_list, n_out_flds);

    OutputFilter = outFilter;
    perm_mat = proj_list;
    nOutFlds = n_out_flds;
    tuple1 = new Tuple();

    try {
      tuple1.setHdr(in1_len, _in1, s1_sizes);
    } catch (Exception e) {
      throw new FileScanException(e, "setHdr() failed");
    }
    t1_size = tuple1.size();

    try {
      f = new Heapfile(file_name);

    } catch (Exception e) {
      throw new FileScanException(e, "Create new heapfile failed");
    }

    try {
      scan = f.openScan();
    } catch (Exception e) {
      throw new FileScanException(e, "openScan() failed");
    }
  }
Ejemplo n.º 2
0
  /**
   * @return the result tuple
   * @exception JoinsException some join exception
   * @exception IOException I/O errors
   * @exception InvalidTupleSizeException invalid tuple size
   * @exception InvalidTypeException tuple type not valid
   * @exception PageNotReadException exception from lower layer
   * @exception PredEvalException exception from PredEval class
   * @exception UnknowAttrType attribute type unknown
   * @exception FieldNumberOutOfBoundException array out of bounds
   * @exception WrongPermat exception for wrong FldSpec argument
   */
  public Tuple get_next()
      throws JoinsException, IOException, InvalidTupleSizeException, InvalidTypeException,
          PageNotReadException, PredEvalException, UnknowAttrType, FieldNumberOutOfBoundException,
          WrongPermat {
    RID rid = new RID();
    ;

    while (true) {
      if ((tuple1 = scan.getNext(rid)) == null) {
        return null;
      }

      tuple1.setHdr(in1_len, _in1, s_sizes);
      if (PredEval.Eval(OutputFilter, tuple1, null, _in1, null) == true) {
        Projection.Project(tuple1, _in1, Jtuple, perm_mat, nOutFlds);
        return Jtuple;
      }
    }
  }