Module datarush.library
Package com.pervasive.datarush.tokens

Interface TokenComparator

  • public interface TokenComparator
    An object for comparing tokens of compatible types. While the interface is generically typed, using TokenValued, implementations are type specific, working on only tokens of one type (or, in the case of the number types, any number type).
    See Also:
    TokenComparators

    • Method Detail

      • getType

        TokenType getType()
        Gets the type of tokens for which the comparator is valid.
        Returns:
        the valid token type for the comparator

      • getDirection

        TokenOrder getDirection()
        Gets the direction of the comparator's ordering.
        Returns:
        the ordering direction

      • setLeftSource

        void setLeftSource​(TokenValued source)
        Binds the left-hand value of the comparator to the specified object. Comparisons will be done using the value of the object at the time of the comparison.
        Parameters:
        source - the value container to use on the left side of comparisons

      • setRightSource

        void setRightSource​(TokenValued source)
        Binds the right-hand value of the comparator to the specified object. Comparisons will be done using the value of the object at the time of the comparison.
        Parameters:
        source - the value container to use on the right side of comparisons

      • equal

        boolean equal()
        Indicates whether the currently bound values are equal. Two values are equal if and only if the following are true:
        • neither value is null valued
        • the contained values are equal (according to the rules of the underlying type)
        This logic is consistent with the behavior of SQL null values.
        Returns:
        true if the bound values are equal, false otherwise.

      • compare

        int compare()
        Indicates the relative ordering of two token values. The ordering is interpreted under the direction associated with the comparator. Thus a descending comparator would place "banana" before "apple", an inversion of the natural (ascending) ordering.

        Null valued tokens always compare equal under this method. Note that this disagrees with the behavior of equal().

        Returns:
        a negative integer, zero, or a positive integer if the bound value for the left is respectively before, equivalent to, or after the bound value for the right.