/**
   Represents a light bulb of some type.
*/
public abstract class LightBulb
{
   private double lumens;

   public LightBulb(double _lumens)
   {
      lumens = _lumens;
   }

   public abstract String getShape();

   /**
      Gets a description of this light bulb.
      @return a string of the form lumensPerWatt=...,shape=... (without any spaces)
   */
   public String getDescription()
   {
      return String.format("lumensPerWatt=%s,shape=%s", lumens, getShape());
   }
}