Introduction to Programming

Chain two Function<T,R>

We can use the andThen(Function after) default method of the Function interface. We have already created the Function<Integer, Double> createMultiplyBy() method:

Function<Integer, Double> createMultiplyBy(double num){  Function<Integer, Double> func = new Function<Integer, Double>(){    public Double apply(Integer i){      return i * num;    }  };  return func; 

We can also write another method that creates a subtracting function with the Double input type, so we can chain it to the multiplying function:

private static Function<Double, Long> createSubtractInt(int num){  Function<Double, Long> func = new Function<Double, Long>(){    public Long apply(Double dbl){      return Math.round(dbl - num);    }  };  return func;}

Now we can write the following ...