Package groovy.lang

Interface Range<T extends Comparable>

  • All Superinterfaces:
    Collection<T>, Iterable<T>, List<T>
    All Known Implementing Classes:
    EmptyRange, IntRange, NumberRange, ObjectRange
    public interface Range<T extends Comparable>
extends List<T>
    A Range represents the list of discrete items between some starting (or from) value and working up towards some ending (or to) value. For a reverse range, the list is obtained by starting at the to value and working down towards the from value. The concept of working up and working down is dependent on the range implementation. In the general case, working up involves successive calls to the first item's next() method while working down involves calling the previous() method. Optimized numerical ranges may apply numeric addition or subtraction of some numerical step size. Particular range implementations may also support the notion of inclusivity and exclusivity with respect to the ending value in the range. E.g. 1..3 == [1, 2, 3]; but 1..<3 == [1, 2]. In general, the second boundary may not be contained in the range, and a..b may produce a different set of elements than (b..a).reversed(). E.g. 1..2.5 == [1, 2]; but 2.5..1 == [2.5, 1.5]. Implementations can be memory efficient by storing just the from and to boundary values rather than eagerly creating all discrete items in the conceptual list. The actual discrete items can be lazily calculated on an as needed basis (e.g. when calling methods from the java.util.List interface or the additional step methods in the Range interface). In addition to the methods related to a Range's "discrete items" abstraction, there is a method, containsWithinBounds which, for numerical ranges, allows checking within the continuous interval between the Range's boundary values.

    • Method Detail

      • getFrom

        T getFrom()
        The lower value in the range.
        Returns:
        the lower value in the range.

      • getTo

        T getTo()
        The upper value in the range.
        Returns:
        the upper value in the range

      • isReverse

        boolean isReverse()
        Indicates whether this is a reverse range which iterates backwards starting from the to value and ending on the from value
        Returns:
        true if this is a reverse range

      • containsWithinBounds

        boolean containsWithinBounds​(Object o)
        Indicates whether an object is greater than or equal to the from value for the range and less than or equal to the to value.

        This may be true even for values not contained in the range. Example: from = 1.5, to = 3, next() increments by 1 containsWithinBounds(2) == true contains(2) == false

        Parameters:
        o - the object to check against the boundaries of the range
        Returns:
        true if the object is between the from and to values

      • step

        void step​(int step,
          Closure closure)
        Steps through the range, calling a closure for each item.
        Parameters:
        step - the amount by which to step. If negative, steps through the range backwards.
        closure - the Closure to call

      • step

        List<T> step​(int step)
        Forms a list by stepping through the range by the indicated interval.
        Parameters:
        step - the amount by which to step. If negative, steps through the range backwards.
        Returns:
        the list formed by stepping through the range by the indicated interval.

      • inspect

        String inspect()
        Returns:
        the verbose String representation of this Range as would be typed into a console to create the Range instance