下载本文示例代码
?编写你自己的 Comparable 类型
Comparable 接口由一个单一的方法构成:
public interface Comparable {
public int compareTo(Object o);
}
compareTo 方法将接收对象与特定对象进行比较，并在接收对象小于、等于或大于特定对象时分别返回负整数、空或一个正整数。如果特定对象不能与接收对象相比较，该方法扔出一个ClassCastException.
这是一个表示某人姓名的类(a class representing a person"s name), 它实现了 Comparable:
import java.util.*;
public class Name implements Comparable {
private String firstName, lastName;
public Name(String firstName, String lastName) {
if (firstName==null || lastName==null)
throw new NullPointerException();
this.firstName = firstName;
this.lastName = lastName;
}
public String firstName() {return firstName;}
public String lastName() {return lastName;}
public boolean equals(Object o) {
if (!(o instanceof Name))
return false;
Name n = (Name)o;
return n.firstName.equals(firstName) &&
n.lastName.equals(lastName);
}
public int hashCode() {
return 31*firstName.hashCode() lastName.hashCode();
}
public String toString() {return firstName " " lastName;}
public int compareTo(Object o) {
Name n = (Name)o;
int lastCmp = lastName.compareTo(n.lastName);
return (lastCmp!=0 ? lastCmp :
firstName.compareTo(n.firstName));
}
}
共9页。 1 2 3 4 5 6 :
?编写你自己的 Comparable 类型
Comparable 接口由一个单一的方法构成:
public interface Comparable {
public int compareTo(Object o);
}
compareTo 方法将接收对象与特定对象进行比较，并在接收对象小于、等于或大于特定对象时分别返回负整数、空或一个正整数。如果特定对象不能与接收对象相比较，该方法扔出一个ClassCastException.
这是一个表示某人姓名的类(a class representing a person"s name), 它实现了 Comparable:
import java.util.*;
public class Name implements Comparable {
private String firstName, lastName;
public Name(String firstName, String lastName) {
if (firstName==null || lastName==null)
throw new NullPointerException();
this.firstName = firstName;
this.lastName = lastName;
}
public String firstName() {return firstName;}
public String lastName() {return lastName;}
public boolean equals(Object o) {
if (!(o instanceof Name))
return false;
Name n = (Name)o;
return n.firstName.equals(firstName) &&
n.lastName.equals(lastName);
}
public int hashCode() {
return 31*firstName.hashCode() lastName.hashCode();
}
public String toString() {return firstName " " lastName;}
public int compareTo(Object o) {
Name n = (Name)o;
int lastCmp = lastName.compareTo(n.lastName);
return (lastCmp!=0 ? lastCmp :
firstName.compareTo(n.firstName));
}
}
共9页。 1 2 3 4 5 6 :
下载本文示例代码
java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下java api 接口篇（二)下
阅读(113) | 评论(0) | 转发(0) |
