Hashtable comparator problem
- by user288245
Hi guys i've never written a comparator b4 and im having a real problem. I've created a hashtable.
Hashtable <String, Objects> ht;
Could someone show how you'd write a comparator for a Hashtable? the examples i've seen overide equals and everything but i simply dont have a clue. The code below is not mine but an example i found, the key thing in hashtables means i cant do it like this i guess.
public class Comparator implements Comparable<Name> {
private final String firstName, lastName;
public void 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));
}
}
