oval.java

此程序可实现：在可视化界面中随即生成一些图形（长方形、椭圆、圆、正方形）；程序会自动告诉你所生成的图形的形状并计算这些图形的面积；最后程序会自动统计各个图形的分布。

import java.util.ArrayList;

/**
 * A class extends GeometricShape to creat ovals.
 * 
 * @author Ruixiao Wu.
 * @version 1.0 26/06/2006.
 */
public class Oval extends GeometricShape {

	final int numOfRandom = 2;

	final int maxRange = 15;

	double area;

	double perimeter;

	ArrayList<Integer> OvalList = new ArrayList<Integer>();

	/**
	 * A method to decide how many ovals are going to created.
	 */
	public int numOfOval() {
		return (int) (Math.random() * 4);
	}

	/**
	 * A method to initial the parameter of the ovals and store them into an
	 * ArrayList.
	 */
	public void initList() {
		OvalList = super.randomNum(numOfRandom, maxRange);
	}

	/**
	 * A method to caculate the area of oval.
	 */
	@Override
	void calculateArea() {
		if (OvalList.get(0) == OvalList.get(1))
			area = Math.PI * OvalList.get(1) * OvalList.get(1);
		else
			area = 0;
	}

	/**
	 * A getter method to get the area of oval.
	 */
	public double getArea() {
		return area;
	}

	/**
	 * A method to caculate the perimeter of oval.
	 */
	@Override
	void calculatePerimeter() {
		if (OvalList.get(0) == OvalList.get(1))
			perimeter = 2 * Math.PI * OvalList.get(1);
		else 
			perimeter = 0;
	}

	/**
	 * A getter method to get the perimeter of oval.
	 */
	public double getPerimeter() {
		return perimeter;
	}
}