sphere.java

mvc模式的示例代码。输入球的半径

import java.util.Observable;
/**
 *
 * <p>Title: The Model part of Application</p>
 * <p>Description: This class represents an observable object,
 * or "data" in the model-view paradigm. It can be subclassed to represent
 * an object that the application wants to have observed. </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * @author Smart Lee
 * @version 1.1
 */
public class Sphere extends Observable {
  // 定义球体半径
  private double sphereRadius;
  // 定义球体体积
  private double sphereVolume;
  // 定义球体表面积
  private double sphereSuArea;

  /**
   * 根据球体半径值设置球体三个属性值
   * @param sphereRadius double
   */
  public void setRadius (double sphereRadius) {
    this.sphereRadius = sphereRadius;
    this.sphereVolume = 4 * Math.PI * Math.pow(sphereRadius, 3) / 3;
    this.sphereSuArea = 4 * Math.PI * Math.pow(sphereRadius, 2);
    //变化后通知视图做相应变化
    setChanged();
    notifyObservers();
  }
  /**
   * 根据球体体积值设置球体三个属性值
   * @param sphereVolume double
   */
  public void setVolume(double sphereVolume) {
    this.sphereVolume = sphereVolume;
    this.sphereRadius = Math.pow(3 * sphereVolume / (4 * Math.PI), 1 / 3.0);
    this.sphereSuArea = 3 * sphereVolume / sphereRadius;
    setChanged();
    notifyObservers();
  }
  /**
   * 根据球体表面积值设置球体三个属性值
   * @param sphereSuArea double
   */
  public void setSuArea(double sphereSuArea) {
    this.sphereSuArea = sphereSuArea;
    this.sphereRadius = Math.pow(sphereSuArea / (4 * Math.PI), 1 / 2.0);
    this.sphereVolume = sphereSuArea * sphereRadius /3;
    setChanged();
    notifyObservers();
  }
  /**
   * 取得球体半径值
   * @return double
   */
  public double getRadius() {
    return sphereRadius;
  }
  /**
   * 取得球体体积值
   * @return double
   */
  public double getVolume() {
    return sphereVolume;
  }
  /**
   * 取得球体表面积值
   * @return double
   */
  public double getSuArea() {
    return sphereSuArea;
  }
}