Java Notes - February 21: Alternate forms of comparison

AlternateHockeyPlayerComparer.java

public class AlternateHockeyPlayerComparer{
    int compare(HockeyPlayer a, HockeyPlayer b){
        String aLastName = a.getLastName();
        String bLastName = b.getLastName();

        int difference = a.lastName.compareTo(b.lastName);
        if(difference != 0){
          return difference;
        }

        String aFirstName = a.getLastName();
        String bFirstName = b.getLastName();
        
        difference = a.firstName.compareTo(b.firstName)
        return difference;
    }

}

Java comparison

- Sorting does Collections.min() repeatedly, comparing pairs of objects at a time
- Only one sort routine, one compareTo method per class
- A compare yourself to B, and tell me which one is bigger?

Alternate forms of comparison
- the long version
- the really short version

- To solve the sorting problem, add a layer to it
- add a separate object whose job it is to compare two objects
- Java already has a built-in object for sorting (comparator interface)
- You can use a comparator object as an inner class
- Anonymous Inner Class, a class within a class without a name
- Anonymous inner classes tend to be more explicit, but slightly difficult to read

Main.java

AlternateHockeyPlayerComparer andre = new AlternateHockeyPlayerComparer();
Collections.sort(aTeam, andre); // takes a list and a comparator object