import java.util.Comparator;
import java.util.SortedSet;
import java.util.TreeSet;

public class TestBeer {

   
  public static void main(String[] args) {
   SortedSet parts = new TreeSet ();
   parts.add(new Beer("Stella Artua", 1000));
   parts.add(new Beer("Obolon", 4562));
   parts.add(new Beer("Slavutich", 9912));
   parts.add(new Beer("Rogan", 1512));
   System.out.println(parts);

   SortedSet <String> sortByDescription = new TreeSet<String>(new Comparator()
         {   
            public int compare(Object a, Object b)
            {
             Beer itemA = (Beer)a;
             Beer itemB = (Beer)b;
             String descrA = itemA.getDescription();
             String descrB = itemB.getDescription();
             return descrA.compareTo(descrB);
            }
         });

      sortByDescription.addAll(parts);
      System.out.println(sortByDescription);

  }

}

class Beer implements Comparable {

   public Beer (String aDescription, int aVolume)
   {   
      description = aDescription;
      volume = aVolume;
   }

   public String getDescription()
   {   
      return description;
   }

   public String toString()
   {   
      return "[descripion=" + description
         + ", volume=" + volume + "]";
   }

   public boolean equals(Object other)
   {   
      if (getClass() == other.getClass())
      {  Beer otherBeer = (Beer)other;
         return description.equals(otherBeer.description)
            && volume == otherBeer.volume;
      }
      else
         return false;
   }

   public int hashCode()
   {   
      return 13 * description.hashCode() + 17 * volume;
   }

   public int compareTo(Object other)
   {   
    Beer otherItem = (Beer)other;
    return volume - otherItem.volume;
   }

   private String description;
   private int volume;
    
   }