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How to convert a class implementing java.lang.Comparable to implement Scala.Ordered?

Is renaming extends Comparable[A] to extends Ordered[A] and renaming def compareTo to def compare enough or is there anything I should take care of?

Solution

  • You're correct, that's all you need to do. The other methods in Ordered will use their default implementations, which go as follows:

    def <  (that: A): Boolean = (this compare that) <  0
def >  (that: A): Boolean = (this compare that) >  0
def <= (that: A): Boolean = (this compare that) <= 0
def >= (that: A): Boolean = (this compare that) >= 0
def compareTo(that: A): Int = compare(that)

    The only thing that doesn't have a default implementation in Ordered is compare, which you'll be defining using your old compareTo method. Should work, provided the above is what you want for your other comparisons.