《Head First设计模式》阅读笔记.第十二章
1、复合（Complex）模式部分

*模式通常被一起使用，并被组合在同一个设计解决方案中。

*复合模式在一个解决方案中结合两个或多个模式，以解决一般或重复发生的问题。

---------------------------------------------public abstract class AbstractGooseFactory{ public abstract Quackable createGoose();}public class GooseFactory extends AbstractGooseFactory{ public Quackable createGoose(){ return new GooseAdapter(new Goose()); }}---------------------------------------------

Sharpen your pencil解答：

---------------------------------------------public class QuackCounter implements Quackable,Observable{  Quackable duck;  static int numberOfQuacks;  Observable observable;    public QuackCounter(Quackable duck){    this.duck=duck;    observable=new Observable(this);  }    public void quack(){    duck.quack();    numberOfQuacks++;  }    public static int getQuacks(){    return numberOfQuacks;  }    public void registerObserver(Observer observer){    observable.registerObserver(observer);  }    public void notifyObservers(){    observable.notifyObservers();  }}---------------------------------------------

Sharpen your public解答：

---------------------------------------------public class Flock implemtns Quackable,observable{  ArrayList quackers=new ArrayList();  Observable observable;    public Flock(){    observable=new Observable(this);  }    public void add(Quackable quacker){    quackers.add(quacker);  }    public void quack(){    Iterator it=quackers.iterator();    While(it.hasNext()){      Quackable quacker=(Quackable)it.next();      quacker.quack();    }  }    public void registerObserver(Observer observer){    Iterator it=quackers.iterator();    While(it.hasNext()){      Quackable quacker=(Quackable)it.next();      quacker.registerObserver(observer);    }  }    public void notifyObservers(){  }}---------------------------------------------

*使用组合（Compose）模式时，需要在安全性和透明性之间折中选择。

2、MVC模式部分（模型Model-视图View-控制器Controller）

*视图（View）：用来呈现模型。视图通常直接从模型中取得它需要显示的数据和状态。

*控制器（Controller）：取得用户的输入并解读其对模型的含义。

*模型（Model）：模型持有所有的数据、状态和程序逻辑。模型没有注意到视图和控制器，虽然它提供了操纵和检索状态的接口，并发送状态改变通知给观察者。

*不把控制器的代码（解读视图的输入并操纵模型）放到模型中的原因有两个：
/** * 观察目标接口 * * @author zangweiren 2010-4-12 * */public interface Observable {void notifyObservers();void registerObserver(Observer observer);}/** * 模型接口 * * @author zangweiren 2010-4-12 * */public interface Ball extends Observable {int getSpeed();void move();void slowDown();void speedUp();void stop();}/** * 模型实现类 * * @author zangweiren 2010-4-12 * */public class BallModel implements Ball {private List<Observer> observers = new ArrayList<Observer>();private int speed = 0;@Overridepublic int getSpeed() {return speed;}@Overridepublic void move() {speed = 10;this.notifyObservers();}@Overridepublic void notifyObservers() {Iterator<Observer> it = observers.iterator();while (it.hasNext()) {Observer observer = it.next();observer.speedChanged();}}@Overridepublic void registerObserver(Observer observer) {observers.add(observer);}@Overridepublic void slowDown() {if (speed > 0) {speed -= 10;this.notifyObservers();}}@Overridepublic void speedUp() {speed += 10;this.notifyObservers();}@Overridepublic void stop() {speed = 0;this.notifyObservers();}}/** * 观察者接口 * * @author zangweiren 2010-4-12 * */public interface Observer {void speedChanged();}/** * 视图 * * @author zangweiren 2010-4-12 * */public class BallView implements Observer {private BallController controller;private Ball ballModel;private JButton move;private JButton stop;private JButton speedUp;private JButton slowDown;private JFrame main = new JFrame();private JPanel ballPanel;private JButton ball;private JLabel speed;private boolean moving = false;public BallView(BallController controller, Ball ballModel) {this.controller = controller;this.ballModel = ballModel;this.ballModel.registerObserver(this);initView();showBall();}private void drawBall(int x, int y) {ball.setLocation(x, y);}private void initView() {main.setTitle("MVC Pattern");main.setSize(300, 200);main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);main.setResizable(false);move = new JButton("Move");stop = new JButton("Stop");speedUp = new JButton(">>");slowDown = new JButton("<<");ballPanel = new JPanel();ball = new JButton();ball.setBackground(Color.RED);ball.setEnabled(false);ball.setSize(20, 20);ball.setLocation(0, 50);JPanel p = new JPanel();p.add(move);p.add(slowDown);p.add(speedUp);p.add(stop);stop.setEnabled(false);speed = new JLabel("Current speed:" + ballModel.getSpeed());JPanel speedPanel = new JPanel();speedPanel.add(speed);main.getContentPane().add(speedPanel, BorderLayout.NORTH);ballPanel.add(ball);main.getContentPane().add(ballPanel);ballPanel.setLayout(null);main.getContentPane().add(p, BorderLayout.SOUTH);main.setVisible(true);move.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {controller.move();}});stop.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {controller.stop();}});speedUp.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {controller.speedUp();}});slowDown.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {controller.slowDown();}});}public void setMoveButtonEnable(boolean b) {move.setEnabled(b);}public void setMoving(boolean b) {this.moving = b;}public void setStopButtonEnable(boolean b) {stop.setEnabled(b);}public void showBall() {new Thread() {@Overridepublic void run() {int x = 0;int y = 50;while (true) {if (!moving) {continue;}drawBall(x, y);try {if (ballModel.getSpeed() != 0) {Thread.sleep(1000 / ballModel.getSpeed());x++;if (x > 290) {x = 0;}} else {Thread.sleep(1000);}} catch (InterruptedException e) {e.printStackTrace();}}}}.start();}@Overridepublic void speedChanged() {speed.setText("Current speed:" + ballModel.getSpeed());}}/** * 控制器 * * @author zangweiren 2010-4-12 * */public class BallController {private Ball ballModel;private BallView view;public BallController(Ball ballModel) {this.ballModel = ballModel;this.view = new BallView(this, ballModel);}public void move() {ballModel.move();view.setMoveButtonEnable(false);view.setStopButtonEnable(true);view.setMoving(true);System.out.println("Ball is moving...");}public void slowDown() {ballModel.slowDown();System.out.println("Slow down:" + ballModel.getSpeed());}public void speedUp() {ballModel.speedUp();System.out.println("Speed up:" + ballModel.getSpeed());}public void stop() {ballModel.stop();view.setMoveButtonEnable(true);view.setStopButtonEnable(false);view.setMoving(false);System.out.println("Ball is stopped.");}}/** * MVC测试类 * * @author zangweiren 2010-4-12 * */public class TestBallView {public static void main(String[] args) {Ball ballModel = new BallModel();new BallController(ballModel);}}