策略模式作业.doc

实验报告1实验内容： Strategy模式的应用某公司专门销售各种打印机，销售打印机时都有一定的折扣让利给顾客，但折扣计算的方法有很多种，如：不打折；每台减扣固定的金额；按售价的5%打折等等，且折扣计算方法可能发生变化。现在要开发该公司的销售系统，实现打印机销售时的价格计算。2实验要求：请用strategy模式设计解决方案。你的方案要能够使得在销售打印机（即使是同一种打印机）时可以灵活的选用价格计算方法，并且可以很容易地增加或修改价格计算方法而不至于对整个系统的维护造成困难。实验报告中要求包含设计方案的类图，并给出相应的Java源程序（要求实现图形用户界面）。类图设计如下：Java源程序：1、策略Strategy.javapublic interface Strategy public abstract double getprice(double price);2、具体策略策略一原价售出StrategyOne.javapublic class StrategyOne implements Strategypublic double getprice(double price)double thePrice = price;return thePrice;策略二减价30元售出StrategyTwo.javapublic class StrategyTwo implements Strategypublic double getprice(double price)double thePrice = price - 30;return thePrice;策略三折扣5%StrategyThree.javapublic class StrategyThree implements Strategypublic double getprice(double price)double thePrice = price * 0.95;return thePrice;3、上下文Printer.javapublic class Printer Strategy strategy;public void setStrategy(Strategy strategy) this.strategy = strategy;public double getPrice(double price)if (strategy != null)return strategy.getprice(price);else return 0;4、模式的使用Application.javaimport java.awt.*;import java.awt.event.*;import javax.swing.*;public class Application implements ActionListener JFrame app;JPanel p1, p2, p3;JLabel label1, label2, label3, label4;JTextField txf;JComboBox combo;JButton button1;public Application() app = new JFrame(Printer);app.setSize(400, 150);app.setVisible(true);Container c = app.getContentPane();/ 初始化String s = 不打折, 减30元, 折扣5%;combo = new JComboBox(s);txf = new JTextField(, 5);button1 = new JButton(计算);label1 = new JLabel(打印机原价：);label2 = new JLabel(价格计算方法：);label3 = new JLabel(折扣后价格：);label4 = new JLabel( 元);/ 将控件放入面板中p1 = new JPanel();p1.add(label1);p1.add(txf);p1.add(label2);p1.add(combo);c.add(p1,BorderLayout.NORTH);p2 = new JPanel();p2.add(label3);p2.add(label4);c.add(p2, BorderLayout.CENTER);p3 = new JPanel();p3.add(button1);c.add(p3, BorderLayout.SOUTH);/ 按钮响应事件button1.addActionListener(this);/ 按钮响应函数public void actionPerformed(ActionEvent e) Price pr = new Price();if (e.getSource() = button1)/ 策略一if (combo.getSelectedItem().equals(不打折)pr.setStrategy(new StrategyOne();label4.setText(pr.getPrice(Double.parseDouble(txf.getText() + 元);/ 策略二if (combo.getSelectedItem().equals(减30元)pr.setStrategy(new StrategyTwo();label4.setText(pr.getPrice(Double.parseDouble(txf.getText() + 元);/ 策略三if (combo.getSelectedItem().equals(折扣5%)pr.setStrategy(new StrategyT