Comparator problems

Hi everyone,

Having a problem in the fact that i have created a Comparator interface and a PersonComparator class. When I try to place this method in another of my classes

public void averages (Player a, Player b)
{
PersonComparator.compare (a, b);
}

i get an error non-static method compare(Player,Player) cannot be referenced from a static context.

As far as I can tell I'm not trying to reference it from a static context...

Any help is much appreciated.

You are, since compare() is a non-static method and you do not have a PersonComparator object to call it on.

Ok, can you expand on that, so I know what I have to do.

Im very new to Java so as basic as possible explanation would be great..

Quote:

---

Originally Posted by kev3kev3

Ok, can you expand on that

---

Lesson: Object-Oriented Programming Concepts (The Java™ Tutorials > Learning the Java Language)

db

Quote:

---

PersonComparator.compare

---

That is the syntax for calling a static method: Classname.methodName(). For example: Math.random()
Change the symbol: PersonComparator to a variable that references the class with the compare method.

I have went from my initial problems to the fact that when i try to call the following in my main method.

Collections.sort (Club.england, new PlayerComparator());

i get this error

cannot find symbol - method sort(java.util.ArrayList<Person>,PlayerComparator) ; maybe you meant: sort(List<T>) or sort(List<T>, Comparator<? super T>)

can someone please help..

Ive been trying to solve this for hours...

Your Comparator needs to match the type used for the List, so your PlayerComparator would need to be:

Code:

---

public class PlayerComparator implements Comparator<Person> {
etc etc
}

---

thanks

such a simple thing