<分区>
我看到这段代码有两个不同的版本，一个来自 Java Oralce，另一个来自 Youtube。两个版本之间的唯一区别是 equals() 方法的参数类型。其中一个是 equals(Object o) 而另一个是 equals(Name o)。我只是想知道这两个版本之间是否有任何有意义的区别？如果是，有什么影响？感谢我能得到的任何帮助!
public class Name implements Comparable<Name> {
private final 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(Name n) {
int lastCmp = lastName.compareTo(n.lastName);
return (lastCmp != 0 ? lastCmp : firstName.compareTo(n.firstName));
}
}