// PieceWorker.java
// PieceWorker類是由 Employee繼承

public final class PieceWorker extends Employee {
   private double wagePerPiece; // 生產量
   private int quantity;        // 工作周數
   // Constructor for class PieceWorker
   public PieceWorker( String first, String last,
                       double w, int q )
   {
      super( first, last );  // 調用父類結構
      setWage( w );
      setQuantity( q );
   }
   
   // 確定工資
   public void setWage( double w ) 
      { wagePerPiece = ( w > 0 ? w : 0 ); }
   
   // 確定工作數量
   public void setQuantity( int q ) 
      { quantity = ( q > 0 ? q : 0 ); }
   
   // 確定計件工人的工資
   public double earnings()
      { return quantity * wagePerPiece; }
   
   public String toString()
   {
      return "計件工人: " + super.toString();
   }  
}