// File:  SetTest.java

// Shows basic set operations add, remove, and contains.

// A HashSet is created and the user can add and remove Strings.  

// Note that attempts to add Strings already in the set are ignored, 
// as are attempts to remove a String that is not in the set.

// The print() method uses an Iterator and Iterator methods hasNext() and 
// next() to retrieve each object in the set.

import java.util.HashSet ;
import java.util.Iterator ;
import java.util.Set ;
import javax.swing.JOptionPane ;

public class SetTest
{
   public static void main(String[] args)
   {
      Set<String> names = new HashSet<String>() ;	

      // add a bunch of names
      
      String input = JOptionPane.showInputDialog
                 ("Add a name (or Cancel when done)") ;
      
      while ( input != null )
      {
         System.out.println("Adding " + input + "...") ;   
         names.add( input ) ;
         print(names) ;
         input = JOptionPane.showInputDialog
                 ("Add a name (or Cancel when done)") ;
      }

      // remove some names
      
	   input = JOptionPane.showInputDialog
                 ("Name to remove? (Cancel when done)") ;
                 	     
      while ( input != null )
      {
         System.out.println("Removing " + input + "...") ;   
         names.remove( input ) ;
         print(names) ;
         input = JOptionPane.showInputDialog
                 ("Name to remove? (Cancel when done)") ;
      }
      
      // do some searches	 
      
      String target = JOptionPane.showInputDialog
                 ("Name to find? (Cancel when done)") ;
      
      while ( target != null )
      {
         if ( names.contains(target) )
         {
         	System.out.println( target + " is in the set" ) ;
         }
         else
         {
           	System.out.println( target + " is NOT in the set" ) ;
		 }
         target = JOptionPane.showInputDialog
                 ("Name to find? (Cancel when done)") ;
      }
   }

   /**
      Prints the contents of a set
      @param s a set
   */
   private static void print(Set s)
   {
      Iterator iter = s.iterator() ;
      System.out.print("{ ") ;
      while (iter.hasNext())
      {
         System.out.print(iter.next() + " ") ;
      }
      System.out.println("}\n") ;      
   }
}

/*   Sample output:
   
Adding Moe...
{ Moe }

Adding Larry...
{ Moe Larry }

Adding Curly...
{ Moe Larry Curly }

Adding Shemp...
{ Moe Shemp Larry Curly }

Removing Moe...
{ Shemp Larry Curly }

Removing Larry...
{ Shemp Curly }

Removing Bob...
{ Shemp Curly }

Shemp is in the set
Curly is in the set
Moe is NOT in the set

*/