Editor2

public class Editor2 implements Ed
{
   private String str;
   private int slice;

   public Editor2( String _str, int index )
   {
       str = _str;
       slice = index;
   }

   public String toString()
   {
       return str.substring( 0, slice ) + "||" + str.substring( slice );
   }

   public String getBefore() { return str.substring( 0, slice );  }
   public String getAfter()  { return str.substring( slice ); }

   // working example that needs error case to be finished
   public Ed rightArrow()
   {
       if (slice == str.length())
         return this;
       return new Editor2( str, slice + 1 );
   }
   public Ed leftArrow()
   {
       if (slice == 0)
           return this;
       return new Editor2( str, slice - 1 );
   }
   public Ed delete()
   {
       if (slice == str.length())
         return this;
       return new Editor2(str.substring(0, slice) + str.substring(slice + 1), slice);
   }
   public Ed backspace()
   {
       if (slice == 0)
          return this;
       return new Editor2( str.substring(0,slice-1) + str.substring(slice), slice - 1 );
   }
   public Ed insertString(String c)  // Originally insert(char c), which is fine if you teach the char type
   {

       return new Editor2( str.substring(0,slice) + c + str.substring(slice), slice );
   }
   public Ed homeKey()
   {
       return new Editor2( str, 0   );
   }

   public Ed endKey()
   {
       return new Editor2( str, str.length() );
   }

   public static void main( String [] args )
   {
       Editor2 eddie = new Editor2( "bigdog", 3 );
       System.out.println( eddie + " right arrow = " + eddie.rightArrow() );
       System.out.println( eddie + " left arrow = " + eddie.leftArrow() );
   }
}