如何实现模板设计模式？

Question

I have this exercise that I need to refactor using Template design pattern. I have seen a basic explanation of how it works, but I can't get a clear idea of how I should implement my solution. Could anyone help me out? What would be the logic in this case?

I have this BodyFatCalculator class:

package bodyfat;

public class BodyFatCalculator {

    private double height;
    private double waist;
    private double weight;
    private double hip;
    private double abdomen;

    public BodyMeasures( double height, double waist, double weight, double hip, double abdomen ) {
    this.height = height;
    this.waist = waist;
    this.weight = weight;
    this.hip = hip;
    this.abdomen = abdomen;
    }

    /**
    * @return the height
    */
    public double getHeight() {
       return height;
    }

    /**
    * @return the waist
    */
    public double getWaist() {
       return waist;
    }

    /**
    * @return the weight
    */
    public double getWeight() {
       return weight;
    }

    /**
    * @return the hip
    */
    public double getHip() {
       return hip;
    }

    /**
    * @return the abdomen
    */
    public double getAbdomen() {
       return abdomen;
    }

}

Answer 1

So, it looks like the way to calculate for men and women is the same except for women use getHip() and men use getAbdomen() . This could be refactored to have a base class BodyFatCalculator define the template for doing this calculation, that calls a "template method" to get the specific implementation of which measurement to use (so, you would add a FemaleBodyFatCalculator and MaleBodyFatCalculator , and they would each override an abstract method like getMiddle(BodyMeassures body) . Female would return body.getHip() and male would return body.getAbdomen() .

So, the gist of it is that your base class has a multi-step algorithm to implement, so it implements the general framework or template, which calls overridable or abstract methods that are implemented by the subclasses.

It seems like a trivial thing to refactor in this case, but such is homework, I guess ;)