public abstract class Shape {
  /**
   * The default size used in constructing a shape.
   */
  protected static final double DEFAULT_SIZE = (double) 1.0;
  protected static final String DEFAULT_NAME = "Unknown";
  private String shapeName;

    /**
     * Construct a generic instance of unknown shape type.
     */
    public Shape(){
      this.shapeName = DEFAULT_NAME;
    }

    /**
     * Construct a <tt>Shape</tt> whose type is specified in
     * the argument.
     * @param name the name of this kind of shape
     */
    public Shape( String name ){
        setShapeName( name );
    }

    /**
     * Reset the shape name for this <tt>Shape</tt>.
     * @param name the name of this kind of shape
     */
    protected void setShapeName( String name ) {
        if ( name.trim().length() == 0 )
            shapeName = DEFAULT_NAME;
        else
            shapeName = new String( name );
    }

    /**
     * Get the name of this kind of shape.
     * @return the name of this shape
     */
    public String getShapeName() {
        return shapeName;
    }

    /**
     * Get the surface area of this <tt>Shape</tt>.
     * @return the surface area of this <tt>Shape</tt>
     */
    public abstract double getSurfaceArea();

    /**
     * Get the perimeter of this <tt>Shape</tt>.
     * @return the perimeter of this <tt>Shape</tt>
     */
    public abstract double getPerimeter();
}