Class FetchDescriptor

java.lang.Object
org.apache.derby.iapi.store.raw.FetchDescriptor

public final class FetchDescriptor extends Object
FetchDescriptor is used to package up all the arguments necessary to describe what rows and what row parts should be returned from the store back to language as part of a fetch.

The FetchDescriptor may also contain scratch space used to process the qualifiers passed in the scan. This scratch space will be used to cache information about the qualifiers, valid column list, row size so that calculations need only be done once per scan rather than every iteration.

  • Field Details

    • row_length

      private int row_length
      Fields of the class
    • validColumns

      private FormatableBitSet validColumns
    • qualifier_list

      private Qualifier[][] qualifier_list
    • materialized_cols

      private int[] materialized_cols
    • maxFetchColumnId

      private int maxFetchColumnId
    • ZERO_FILL_LENGTH

      private static final int ZERO_FILL_LENGTH
      See Also:
    • zero_fill_array

      private static final int[] zero_fill_array
    • validColumnsArray

      private int[] validColumnsArray
  • Constructor Details

    • FetchDescriptor

      FetchDescriptor()
      Constructors for This class:
    • FetchDescriptor

      public FetchDescriptor(int input_row_length)
    • FetchDescriptor

      public FetchDescriptor(int input_row_length, int single_valid_column_number)
    • FetchDescriptor

      public FetchDescriptor(int input_row_length, FormatableBitSet input_validColumns, Qualifier[][] input_qualifier_list)
  • Method Details

    • getValidColumns

      public final FormatableBitSet getValidColumns()
      Return the column list bit map.

      A description of which columns to return from every fetch in the scan. A row array and a valid column bit map work together to describe the row to be returned by the scan - see RowUtil for description of how these two parameters work together to describe a "row".

      Returns:
      The column list bit map.
    • getValidColumnsArray

      public final int[] getValidColumnsArray()
    • setValidColumns

      public final void setValidColumns(FormatableBitSet input_validColumns)
    • getQualifierList

      public final Qualifier[][] getQualifierList()
      Return the qualifier array.

      Return the array of qualifiers in this FetchDescriptor. The array of qualifiers which, applied to each key, restricts the rows returned by the scan. Rows for which any one of the qualifiers returns false are not returned by the scan. If null, all rows are returned. Qualifiers can only reference columns which are included in the scanColumnList. The column id that a qualifier returns in the column id the table, not the column id in the partial row being returned.

      A null qualifier array means there are no qualifiers.

      Returns:
      The qualifier array, it may be null.
    • getMaterializedColumns

      public final int[] getMaterializedColumns()
      Internal to store.
    • getMaxFetchColumnId

      public final int getMaxFetchColumnId()
      Internal to store.
    • setMaxFetchColumnId

      private final void setMaxFetchColumnId()
    • reset

      public final void reset()
      Internal to store.