source: utilitiespy/tudelft/utilities/tools/comparator.py

from abc import ABC, abstractmethod
from typing import TypeVar, Generic, Any

T=TypeVar("T")

class Comparator(Generic[T]):
  
    @abstractmethod
    def compare(self, o1:T, o2:T)-> int:
        '''
           Compares its two arguments for order.  Returns a negative integer,
          zero, or a positive integer as the first argument is less than, equal
          to, or greater than the second.<p>
         
          The implementor must ensure that {@code sgn(compare(x, y)) ==
          -sgn(compare(y, x))} for all {@code x} and {@code y}.  (This
          implies that {@code compare(x, y)} must throw an exception if and only
          if {@code compare(y, x)} throws an exception.)<p>
         
          The implementor must also ensure that the relation is transitive:
          {@code ((compare(x, y)>0) && (compare(y, z)>0))} implies
          {@code compare(x, z)>0}.<p>
         
          Finally, the implementor must ensure that {@code compare(x, y)==0}
          implies that {@code sgn(compare(x, z))==sgn(compare(y, z))} for all
          {@code z}.<p>
         
          It is generally the case, but <i>not</i> strictly required that
          {@code (compare(x, y)==0) == (x.equals(y))}.  Generally speaking,
          any comparator that violates this condition should clearly indicate
          this fact.  The recommended language is "Note: this comparator
          imposes orderings that are inconsistent with equals."<p>
         
          In the foregoing description, the notation
          {@code sgn(}<i>expression</i>{@code )} designates the mathematical
          <i>signum</i> function, which is defined to return one of {@code -1},
          {@code 0}, or {@code 1} according to whether the value of
          <i>expression</i> is negative, zero, or positive, respectively.
         
          @param o1 the first object to be compared.
          @param o2 the second object to be compared.
          @return a negative integer, zero, or a positive integer as the
                  first argument is less than, equal to, or greater than the
                  second.
          @raises ValueError if an argument is null and this
                  comparator does not permit null arguments
          @raises ClassCastException if the arguments' types prevent them from
                  being compared by this comparator.
         
        '''
        pass


class DefaultComparator(Comparator[Any]):
    def compare(self, o1:Any, o2:Any)-> int:
        return -1 if o1<o2 else 1 if o1>o2 else 0