转换为通用 class

Question

我无法理解泛型概念。我需要将 class DataSet 转换为其通用形式。我尤其不知道如何处理 DataSet 的字段。我明白我们必须用 T 替换所有签名。

/**
   Computes the average of a set of data values.
*/
public class DataSet
{
   private double sum;
   private Measurable maximum;
   private int count;

   /**
  Constructs an empty data set.
  */
   public DataSet()
   {
      sum = 0;
      count = 0;
      maximum = null;
   }

   /**
      Adds a data value to the data set.
      @param x a data value
   */
   public void add(Measurable x)
   {
      sum = sum + x.getMeasure();
      if (count == 0 || maximum.getMeasure() <       x.getMeasure())
          maximum = x;
         count++;
        }

   /**
      Gets the average of the added data.
      @return the average or 0 if no data has been added
   */
   public double getAverage()
   {
      if (count == 0) return 0;
      else return sum / count;
   }

   /**
      Gets the largest of the added data.
      @return the maximum or 0 if no data has been added
   */
   public Measurable getMaximum()
   {
      return maximum;
   }
}

更新：这是我想出的解决方案：

public class DataSetGen <T>
{
   private double sum;
   private T maximum;
   private int count;

   /**
      Constructs an empty data set.
   */
   public DataSetGen()
   {
      sum = 0;
      count = 0;
      maximum = null;
   }

   /**
      Adds a data value to the data set.
      @param x a data value
   */
   public void add(T x)
   {
      sum = sum + x.getMeasure();
      if (count == 0 || maximum.getMeasure() < x.getMeasure())
         maximum = x;
      count++;
   }

   /**
      Gets the average of the added data.
      @return the average or 0 if no data has been added
   */
   public double getAverage()
   {
      if (count == 0) return 0;
      else return sum / count;
   }

   /**
      Gets the largest of the added data.
      @return the maximum or 0 if no data has been added
   */
   public T getMaximum()
   {
      return maximum;
   }
}

Answer 1

首先问自己这个问题 "This is supposed to be a set of ???"。在您的情况下，它可能是 Measurable.

的一组子类

既然你已经有了这个，你应该能够弄清楚将泛型类型放在哪里。

转换为通用 class

Converting into Generic class

java

generics

generic-programming