实现和接口

时间:2012-02-25 16:30:09

标签: java interface implementation

我尝试查找教程和视频,并了解实现的内容,尽管我对如何从Java库实现类感到困惑。在我的作业中,我想要利用类DataSet并使其接受Comparable对象。该程序假设根据对象记录最小值和最大值,在这种情况下,我想使用字符串。我不确定我是否需要任何类来实现Comparable接口,所以我做了两个类以防万一我想这样做。我真正的问题是如何在测试器类中实际包含一个String变量来实际读取并将对象与另一个对象进行比较?提前谢谢。

public class Word implements Comparable
{
private String str;

public Word()
{
    str = null;
}

public Word(String s)
{
    str = s;
}

 public int compareTo(Object other)
 {
    String n = (String) other;
    return str.compareTo(n);
 }

}

我不确定这两个类中哪一个适合实现虽然我认为下面的String类根本不起作用b / c它已经是标准类所以我不太确定使用它

public class String implements Comparable
{
    public String s;

    public String()
    {
    s = null;
    }

public String(String str)
{
    s = str;
}
public int compareTo(Object other)
{
    String n = (String) other;
   return s.compareTo(n);
}
}


public interface Comparable
{
public int compareTo(Object other);
}


public class DataSet
{
 private Object maximum;
 private Object least;
 private Comparable compare;
 private int count;

 public DataSet(Comparable s)
 {
   compare = s;
 }

 public void add(Object x)
 {

   if(count == 0)
   least = x;
   if(count == 0 || compare.compareTo(x) >=0)
   maximum = x;
   else if(compare.compareTo(x) <0)
   least = x;
   count++;

 }
 public Object getMaximum()
 {
  return maximum;
 }

 public Object getLeast()
 {
   return least;
 }

 }


public class DataSetTester
{
   public static void main(String[] args)
  {
  Comparable n = new Word("sand");
  DataSet data = new DataSet(n);


  data.add(new Word(man));



  System.out.println("Maximum Word: " + data.getMaximum());
  System.out.println("Least Word: " + data.getLeast());
 }
}

1 个答案:

答案 0 :(得分:0)

接口是一个合同,表明您的类包含接口中实现的所有方法。在这种情况下CompareTo(object other)。 String类已经实现了类似的接口,因此您不需要自己的类。我认为你的数据集类应该是这样的:

public class DataSet<T implements Comparable>
{
 private T maximum;
 private T least;
 private T count;


 public void add(T x)
 {

   if(count == 0){
     least = x;
     maximum = x;
   }
   else if(least.compareTo(x) > 0)
     least = x;
   else if(maximum.compareTo(x) < 0)
     maximum = x;
   count++;
 }

 public T getMaximum()
 {
  return maximum;
 }

 public T getLeast()
 {
   return least;
 }

 }

T是泛型类型,在您的情况下它应该是String,以下是创建新数据集的方法: DataSet<String> ds = new DataSet<String>;