java 将方法作为传参--多态的实例

public interface Fitness {
 public double getFitness(double X);
}

public class stationUtils{/***
 * 黄金分割搜索法,寻找最小值的函数
 * @param min 搜索上限
 * @param max 搜索下限
 * @param fitness 函数值
 * @return
 */
 public double goldenSearch(double min,double max,Fitness fitness){
  /*double X1=min+0.382*(max-min);*/
  double a=doubleOperation.substract(max,min);
  double X1=doubleOperation.add(min,doubleOperation.multiply(0.382,a));
  /*double X2=min+0.618*(max-min);*/
  double X2=doubleOperation.add(min,doubleOperation.multiply(0.618,a));
  double F1=fitness.getFitness(X1);
  double F2=fitness.getFitness(X2);
  while(Math.abs(doubleOperation.substract(X1,X2))>delt){
   if(F1<F2){
   max=X2;
   X2=X1;
   F2=F1;
   X1=min+0.382*(max-min);
   F1=fitness.getFitness(X1);
   }else{
   min=X1;
   X1=X2;
   F1=F2;
   X2=min+0.618*(max-min);
   F2=fitness.getFitness(X2);
   }
  }
  return doubleOperation.divide(doubleOperation.add(max,min),2);

 }
}

 public class Func implements Fitness{
  @Override
  public double getFitness(double X) {
   return X*X- 3 * X + 1;
  }
 }

 @Test
 public void run1(){
  Func func=new Func();
  double result=stationUtils.goldenSearch(-2.00,4.00,func);
  System.out.println(result);
 }