Interface ValueScale

All Known Implementing Classes:
ValueScale.Anchored, ValueScale.Percent, ValueScale.Range, ValueScale.RatioToBest
public sealed interface ValueScale permits ValueScale.Range, ValueScale.Percent, ValueScale.RatioToBest, ValueScale.Anchored
How an objective's raw value becomes a 0..100 score (100 = best) for the weighted ranking.

The choice matters. A scale that depends on the spread of the options being compared (ValueScale.Range) turns any difference, however small, into the full 0..100 span: when every option costs within 7% of every other, the dearest still scores 0 and the cheapest 100, so a trivial saving outweighs a large, real difference in another objective. It also lets an irrelevant option change the order of two others. The other scales are fixed by the objective's meaning, so a score says how good a value is, not where it happens to fall among the candidates.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static final record 
    ValueScale.Anchored
    Linear between two fixed anchors, clamped.
    static final record 
    ValueScale.Percent
    The value is a percentage: it is the score when larger is better, and 100 minus it otherwise.
    static final record 
    ValueScale.Range
    Min-max over the options being ranked.
    static final record 
    ValueScale.RatioToBest
    The ratio to the best value: an option 7% dearer than the cheapest scores about 93, one twice as dear scores 50.

  • Method Summary

    Modifier and Type
    Method
    Description
    static ValueScale
    anchored(double bestAt, double worstAt)
     
    String
    describe()
     
    static ValueScale
    percent()
     
    static ValueScale
    range()
     
    static ValueScale
    ratioToBest()
     
    double
    score(double value, double best, double worst, Direction direction)
     

  • Method Details

    • score

      double score(double value, double best, double worst, Direction direction)
      Parameters:
      value - the raw value (never NaN)
      best - the best value among the options being ranked
      worst - the worst value among the options being ranked
      direction - whether smaller or larger is better
      Returns:
      the score, 0..100

    • describe

      String describe()
      Returns:
      a one-line description for reports

    • range

      static ValueScale range()
      Returns:
      the scale relative to the spread of the options: the best scores 100, the worst 0

    • percent

      static ValueScale percent()
      Returns:
      the scale for a value that already is a 0..100 percentage

    • ratioToBest

      static ValueScale ratioToBest()
      Returns:
      the scale that scores a value by its ratio to the best one (for money and other positive amounts)

    • anchored

      static ValueScale anchored(double bestAt, double worstAt)
      Parameters:
      bestAt - the value that scores 100 (and anything better)
      worstAt - the value that scores 0 (and anything worse)
      Returns:
      a fixed linear scale between two anchors