Class CollatedBaseSearch

  • Direct Known Subclasses:
    InsertSearch

    public abstract class CollatedBaseSearch
    extends SelectableScheme
    An implementation of SelectableScheme that is based on some collated set of data. This can be used to implement more advanced types of selectable schemes based on presistant indexes (see InsertSearch).

    The default implementation maintains no state,

    Derived classes are required to implement 'copy', 'searchFirst' and 'searchLast' methods. With these basic methods, a selectable scheme can be generated provided the column is sorted in ascending order (value of row i is <= value of row i+1). Overwrite 'firstInCollationOrder', 'lastInCollationOrder' and 'addRangeToSet' methods for non sorted underlying sets.

    Assumptions - the underlying column is sorted low to high (value of row i is <= value of row i+1).

    Author:
    Tobias Downer
    • Constructor Detail

      • CollatedBaseSearch

        public CollatedBaseSearch​(TableDataSource table,
                                  int column)
        The Constructor.
    • Method Detail

      • insert

        public void insert​(int row)
        This scheme doesn't take any notice of insertions or removals.
      • remove

        public void remove​(int row)
        This scheme doesn't take any notice of insertions or removals.
      • readFrom

        public void readFrom​(java.io.InputStream in)
                      throws java.io.IOException
        Reads the entire state of the scheme from the input stream. This is a trivial case for BlindSearch which doesn't require any data to be stored.
        Specified by:
        readFrom in class SelectableScheme
        Throws:
        java.io.IOException
      • writeTo

        public void writeTo​(java.io.OutputStream out)
                     throws java.io.IOException
        Writes the entire state of the scheme to the output stream. This is a trivial case for BlindSearch which doesn't require any data to be stored.
        Specified by:
        writeTo in class SelectableScheme
        Throws:
        java.io.IOException
      • dispose

        public void dispose()
        Disposes and invalidates the BlindSearch.
        Specified by:
        dispose in class SelectableScheme
      • searchFirst

        protected abstract int searchFirst​(TObject val)
        Finds the position in the collated set of the first value in the column equal to the given value. If the value is not to be found in the column, it returns -(insert_position + 1).
      • searchLast

        protected abstract int searchLast​(TObject val)
        Finds the position in the collated set of the last value in the column equal to the given value. If the value is not to be found in the column, it returns -(insert_position + 1).
      • setSize

        protected int setSize()
        The size of the set (the number of rows in this column).
      • firstInCollationOrder

        protected TObject firstInCollationOrder()
        Returns the first value of this column (in collated order). For example, if the column contains (1, 4, 8} then '1' is returned.
      • lastInCollationOrder

        protected TObject lastInCollationOrder()
        Returns the last value of this column (in collated order). For example, if the column contains (1, 4, 8} then '8' is returned.
      • addRangeToSet

        protected IntegerVector addRangeToSet​(int start,
                                              int end,
                                              IntegerVector ivec)
        Adds the set indexes to the list that represent the range of values between the start (inclusive) and end offset (inclusive) given.
      • selectAll

        public IntegerVector selectAll()
        Description copied from class: SelectableScheme
        These are the select operations that are the main purpose of the scheme. They retrieve the given information from the set. Different schemes will have varying performance on different types of data sets. The select operations must *always* return a resultant row set that is sorted from lowest to highest.
        Overrides:
        selectAll in class SelectableScheme