// We define our own order relation on strings. Strings are ordered by length.
//
import java.util.*;

public class MyString implements Comparable<MyString> {

  public String contents;
  
  public MyString(String s) {
        contents = s;
     }

  public int getLength() { return contents.length(); }

  public String toString() { return contents; }
         
// Redefine equality to be compatible --- not necessary but a good idea.
// Note that you have to redefine the equals method that takes an Object
// argument, since that's what existing methods that call equals will be
// looking for. So you have to do a cast.
//
  public boolean equals(Object o) {
      if (!(o instanceof MyString)) return false;
      MyString s = (MyString) o;              // cast Object to String
      return getLength() == s.getLength();
     }

  public int compareTo(MyString s) {
     if (getLength() < s.getLength()) return -1;
     else if (getLength() > s.getLength()) return 1;
     else return 0;
   }

  public int hashCode() {
     return (new Integer(getLength()).hashCode()); 
    }

  public static void main(String[] args) {
      MyString how = new MyString("How");
      MyString much = new MyString("much");
      MyString wood = new MyString("wood");
      MyString could = new MyString("could");
      System.out.println("much.equals(wood) => " + 
             ( much.equals(wood) ? "true" : "false"));
      System.out.println("how.compareTo(could) => " +
             how.compareTo(could));
      List<MyString> l = new ArrayList<MyString>();
      l.add(wood); l.add(how); l.add(could); l.add(much);
      Collections.sort(l);
      System.out.println(l);
      HashMap<MyString,Integer> h = new HashMap<MyString,Integer>();
      h.put(much, 15);
      System.out.println(h.get(wood));
  }
}