读书笔记_java设计模式深入研究第八章状态模式 State

1，状态模式：事务有n个状态，且维护状态变化。

2，UML模型：

-1，上下文环境Context：定义客户程序需要的接口并维护一个具体状态角色的实例，将与状态相关的操作委托给当前的Concrete State对象来处理。

-2，抽象状态State：定义接口以封装上下文环境的一个特定状态的行为。

-3，具体状态ConcreteState：具体状态。

3，简单代码：

 
package pattern.chp08.state.simple;
 
/**
 *  类描述：状态抽象接口
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 10:44:21 AM   Jing   Created.
 *           
 */
public interface IState {
	/**
	 * 
	 * 方法说明：状态更改
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 10:44:44 AM
	 *
	 * @return void
	 */
	void goState();
}

package pattern.chp08.state.simple;
 
/**
 *  类描述：状态B
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 10:50:24 AM   Jing   Created.
 *           
 */
public class ConcreteStateB implements IState{
 
	public void goState() {
		
		System.out.println("ConcreteStateB");
	}
 
}

package pattern.chp08.state.simple;
 
/**
 *  类描述：状态A
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 10:50:04 AM   Jing   Created.
 *           
 */
public class ConcreteStateA implements IState {
 
	public void goState() {
		
		System.out.println("ConcreteStateA");
	}
 
}

package pattern.chp08.state.simple;
 
/**
 * 类描述：上下文
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 10:52:03 AM Jing Created.
 * 
 */
public class Context {
 
	private IState state;
 
	public void setState(IState state) {
		this.state = state;
	}
	/**
	 * 
	 * 方法说明：根据条件选择某种状态
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 10:52:51 AM
	 *
	 * @return void
	 */
	public void manage(){
		
		state.goState();
	}
}

4，深入理解状态模式

-1，利用上下文类控制状态

手机应用，假设手机功能有存款和打电话，状态有正常、透支、停机。使用状态模式模拟：

 
package pattern.chp08.state.cellState;
 
/**
 *  类描述：手机状态接口
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 11:04:09 AM   Jing   Created.
 *           
 */
public interface ICellState {
	/**
	 * 正常状态
	 */
	public float NORMAL_LIMIT = 0;
	/**
	 * 停机状态
	 */
	public float STOP_LIMIT = -1;
	/**
	 * 话费标准
	 */
	public float COST_MINUTE = 0.20F;
	/**
	 * 
	 * 方法说明：电话
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 11:21:01 AM
	 *
	 * @param ct
	 * @return
	 * @return boolean
	 */
	boolean phone(CellContext ct);
	
	
}

package pattern.chp08.state.cellState;
 
/**
 * 类描述：正常状态
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 11:35:54 AM Jing Created.
 * 
 */
public class NormalState implements ICellState {
 
	public boolean phone(CellContext ct) {
 
		System.out.println(ct.name + ": 处于正常状态");
 
		int minute = (int) (Math.random() * 10 + 1);// 随机产生打电话分钟数
		ct.cost(minute);
		//some save code 
		
		return false;
	}
 
}

package pattern.chp08.state.cellState;
 
/**
 *  类描述：透支状态下电话类
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 11:36:47 AM   Jing   Created.
 *           
 */
public class OverDrawState implements ICellState {
 
	public boolean phone(CellContext ct) {
		System.out.println(ct.name + ": 处于透支状态");
 
		int minute = (int) (Math.random() * 10 + 1);// 随机产生打电话分钟数
		ct.cost(minute);
		//some save code 
		
		return false;
	}
 
}

package pattern.chp08.state.cellState;
 
/**
 * 类描述：停机状态
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 11:36:23 AM Jing Created.
 * 
 */
public class StopState implements ICellState {
 
	public boolean phone(CellContext ct) {
		System.out.println(ct.name + ": 处于停机状态");
		return false;
	}
 
}

 
package pattern.chp08.state.cellState;
 
/**
 * 类描述：手机上下文状态类
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 11:30:09 AM Jing Created.
 * 
 */
public class CellContext {
 
	String strPhone;// 电话号码
	String name;// 姓名
	float price;// 金额
 
	public CellContext(String strPhone, String name, float price) {
		this.strPhone = strPhone;
		this.name = name;
		this.price = price;
	}
	/**
	 * 
	 * 方法说明：手机存钱
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 11:31:41 AM
	 *
	 * @param price
	 * @return void
	 */
	public void save(float price){
		
		this.price += price;
	}
	/**
	 * 
	 * 方法说明：手机话费
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 11:32:13 AM
	 *
	 * @param minute
	 * @return void
	 */
	public void cost(int minute){
		
		
		this.price -= ICellState.COST_MINUTE * minute;
	}
	/**
	 * 
	 * 方法说明：获取不同手机状态
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 11:33:15 AM
	 *
	 * @return
	 * @return boolean
	 */
	public boolean call(){
		ICellState state = null;
		if(price > ICellState.NORMAL_LIMIT){
			
			state = new NormalState();
		}else if(price < ICellState.STOP_LIMIT){
			
			state = new StopState();
		}else{
			
			state = new OverDrawState();
		}
		
		state.phone(this);
		
		return true;
		
	}
	
	
 
}

/**
 *  类描述：
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 2:25:14 PM   Jing   Created.
 *           
 */
public class Test {
 
	public static void main(String[] args) {
		
		CellContext c = new CellContext("213130", "LaoLiu", 1);
		c.call();
		c.call();
	}
}

5，应用探索

计算机内存监控

 
package pattern.chp08.state.ctrl;
 
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
 
/**
 * 类描述：参数控制面板
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 2:35:38 PM Jing Created.
 * 
 */
public class CtrlPanel extends JPanel {
 
	private static final long serialVersionUID = -6539318368246202726L;
 
	JComponent[] c = { new JTextField(4), new JTextField(4), new JButton("开始检测"),
			new JButton("停止检测") };
 
	boolean bmark[][] = { { true, true, true, false }, { false, false, false, true } };
 
	ActionListener startAct = new ActionListener() {// 开始检测 按钮响应事件
 
		public void actionPerformed(ActionEvent e) {
 
			setState(1);// 设置组件为初始状态
 
			int high = Integer.parseInt(((JTextField) c[0]).getText());
			int low = Integer.parseInt(((JTextField) c[1]).getText());
 
			Container c = CtrlPanel.this.getParent();
			String className = c.getClass().getName();
			while (!"pattern.chp08.state.ctrl.MyFrame".equalsIgnoreCase(className)) {
 
				c = c.getParent();
				className = c.getClass().getName();
			}
			((MyFrame) c).startMonitor(high, low);
		}
 
	};
 
	ActionListener stopAct = new ActionListener() {// 停止检测 按钮响应
 
		public void actionPerformed(ActionEvent e) {
 
			setState(0);
			Container c = CtrlPanel.this.getParent();
			String className = c.getClass().getName();
			while (!"pattern.chp08.state.ctrl.MyFrame".equalsIgnoreCase(className)) {
 
				c = c.getParent();
				className = c.getClass().getName();
			}
			((MyFrame) c).stopMonitor();
		}
	};
 
	public CtrlPanel() {
 
		add(new JLabel("优良"));
		add(c[0]);
		add(new JLabel("良好"));
		add(c[1]);
		add(c[2]);
		add(c[3]);
		setState(0);// 设置初始
 
		((JButton) c[2]).addActionListener(startAct);
		((JButton) c[3]).addActionListener(stopAct);
 
	}
 
	/**
	 * 
	 * 方法说明：设置按钮状态
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 2:42:17 PM
	 * 
	 * @param nState
	 * @return void
	 */
	void setState(int nState) {
 
		for (int i = 0; i < bmark[nState].length; i++) {
 
			c[i].setEnabled(bmark[nState][i]);
		}
	}
 
}

 
package pattern.chp08.state.ctrl;
 
import javax.swing.Box;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.BevelBorder;
 
/**
 *  类描述：中间数值展示面板类
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 3:02:21 PM   Jing   Created.
 *           
 */
public class ContentPanel extends JPanel {
 
	private static final long serialVersionUID = 3347768107958337339L;
	
	JTextField totalField = new JTextField(20);//总内存展示
	JTextField freeField = new JTextField(20);//空闲内存显示
	JTextField ratioField = new JTextField(20);//空闲率展示
	
	@SuppressWarnings("static-access")
	public ContentPanel() {
		
		totalField.setEditable(false);
		freeField.setEditable(false);
		ratioField.setEditable(false);
		
		Box b1 = Box.createVerticalBox();
		b1.add(new JLabel("总内存："));
		b1.add(b1.createVerticalStrut(16));
		
		b1.add(new JLabel("空闲内存："));
		b1.add(b1.createVerticalStrut(16));
		
		b1.add(new JLabel("所占比例："));
		b1.add(b1.createVerticalStrut(16));
		
		Box b2 = Box.createVerticalBox();
		b2.add(totalField);
		b2.add(b2.createVerticalStrut(16));
 
		b2.add(freeField);
		b2.add(b2.createVerticalStrut(16));
 
		b2.add(ratioField);
		b2.add(b2.createVerticalStrut(16));
		
		add(b1);
		add(b2);
		setBorder(new BevelBorder(BevelBorder.RAISED));
	}
	/**
	 * 
	 * 方法说明：设置对应Field值
	 *
	 * Author：       Jing                
	 * Create Date：   Dec 26, 2014 3:11:22 PM
	 *
	 * @param value
	 * @param free
	 * @param ratio
	 * @return void
	 */
	void setValue(long value, long free, long ratio){
		
		totalField.setText(value + " M");
		freeField.setText(free + "  M");
		ratioField.setText(ratio + "%");
	}
	
	
}

 
package pattern.chp08.state.ctrl;
 
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
 
/**
 * 类描述：上下文类
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 3:24:15 PM Jing Created.
 * 
 */
public class StatePanel extends JPanel {
 
	private static final long serialVersionUID = 1L;
 
	JTextField txtInfo = new JTextField(4);
	JTextField txtHour = new JTextField(10);
	IState state;
	int mark = -1;
 
	public StatePanel() {
 
		add(new JLabel("当前内存状态： "));
		add(txtInfo);
		add(new JLabel("持续时间： "));
		add(txtHour);
		txtInfo.setEnabled(false);
		txtHour.setEnabled(false);
	}
 
	/*
	 * 设置内存状态
	 */
	public void setState(int mark) {
 
		if (this.mark == mark) {// 内存无变化
 
			return;
		}
		this.mark = mark;
		switch (mark) {
		case 1:
			state = new HighState();
			break;
		case 2:
			state = new MidState();
			break;
		case 3:
			state = new LowState();
			break;
		}
	}
 
	/**
	 * 
	 * 方法说明：设置对应值
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:31:39 PM
	 * 
	 * @return void
	 */
	public void process() {
 
		txtInfo.setText(state.getStateInfo());
		int size = state.getStateInterval();
		//DecimalFormat df = new DecimalFormat("0.00");
		txtHour.setText("" + /*df.format((float) size / 3600)*/  size + "  S");
	}
 
}

package pattern.chp08.state.ctrl;
 
/**
 * 类描述：状态接口
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 3:17:18 PM Jing Created.
 * 
 */
public interface IState {
	/**
	 * 
	 * 方法说明：获取状态信息
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:17:45 PM
	 * 
	 * @return
	 * @return String
	 */
	String getStateInfo();
 
	/**
	 * 
	 * 方法说明：获取统计频率
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:18:12 PM
	 * 
	 * @return
	 * @return int
	 */
	int getStateInterval();
}

package pattern.chp08.state.ctrl;
 
/**
 * 类描述：内存紧张
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 3:19:28 PM Jing Created.
 * 
 */
public class LowState implements IState {
 
	private int times;
 
	public String getStateInfo() {
		
		//some other code 
		//此处可设置通知管理员等其他代码
		return "一般";
	}
 
	public int getStateInterval() {
 
		return times++;
	}
 
}

package pattern.chp08.state.ctrl;
 
/**
 * 类描述：内存充足
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 3:18:56 PM Jing Created.
 * 
 */
public class HighState implements IState {
 
	private int times;
 
	public String getStateInfo() {
		
		//some other code 
		//此处可设置通知管理员等其他代码
		return "充足";
	}
 
	public int getStateInterval() {
		return times++;
	}
 
}

package pattern.chp08.state.ctrl;
 
/**
 *  类描述：内存良好
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 3:19:12 PM   Jing   Created.
 *           
 */
public class MidState implements IState {
 
	private int times;
	
	public String getStateInfo() {
		
		//some other code 
		//此处可设置通知管理员等其他代码
		return "良好";
	}
 
	public int getStateInterval() {
 
		return times++;
	}
 
}

 
package pattern.chp08.state.ctrl;
 
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.JFrame;
import javax.swing.Timer;
 
import sun.management.ManagementFactory;
 
import com.sun.management.OperatingSystemMXBean;
 
/**
 * 类描述：主窗口
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 26, 2014 3:47:44 PM Jing Created.
 * 
 */
public class MyFrame extends JFrame implements ActionListener {
 
	private static final long serialVersionUID = 1L;
 
	CtrlPanel ctrlPanel = new CtrlPanel();// 参数面板
	ContentPanel contentPanel = new ContentPanel();// 数值显示面板
	StatePanel statePanel = new StatePanel();// 状态面板
 
	Timer timer = new Timer(1000, this);// 定时器
 
	int high, mid;
 
	/**
	 * 
	 * 方法说明：初始化
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:51:54 PM
	 * 
	 * @return void
	 */
	public void init() {
 
		add(ctrlPanel, BorderLayout.NORTH);
		add(contentPanel, BorderLayout.CENTER);
		add(statePanel, BorderLayout.SOUTH);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setSize(500, 220);
		setVisible(true);
	}
 
	/**
	 * 
	 * 方法说明：启动自动检测
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:53:53 PM
	 * 
	 * @param high
	 * @param mid
	 * @return void
	 */
	public void startMonitor(int high, int mid) {
 
		this.high = high;
		this.mid = mid;
 
		timer.start();
 
	}
 
	/**
	 * 
	 * 方法说明：停止检测
	 * 
	 * Author： Jing Create Date： Dec 26, 2014 3:54:51 PM
	 * 
	 * @return void
	 */
	public void stopMonitor() {
 
		timer.stop();
	}
 
	public void actionPerformed(ActionEvent e) {// 定时器响应方法
 
		OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory
				.getOperatingSystemMXBean();
		long total = osmxb.getTotalPhysicalMemorySize();
		long free = osmxb.getFreePhysicalMemorySize();
		int ratio = (int) (free * 100L / total);
 
		contentPanel.setValue(total / (1024 * 1024), free / (1024 * 1024), ratio);
 
		int mark = -1;
		if (ratio >= high) {
 
			mark = 1;
		} else if (ratio < mid) {
 
			mark = 3;
		} else {
 
			mark = 2;
		}
 
		statePanel.setState(mark);
		statePanel.process();
	}
 
}

package pattern.chp08.state.ctrl;
 
/**
 *  类描述：
 * 
 *  @author:  Jing
 *  @version  $Id: Exp$ 
 *
 *  History:  Dec 26, 2014 4:02:27 PM   Jing   Created.
 *           
 */
public class Test {
 
	public static void main(String[] args) {
		
		new MyFrame().init();
	}
}

运行界面：

posted @ 2014-12-29 10:21 梅尔加德斯阅读(234) 评论(0) 编辑收藏举报

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读书笔记_java设计模式深入研究第八章状态模式 State

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读书笔记_java设计模式深入研究 第八章 状态模式 State

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读书笔记_java设计模式深入研究第八章状态模式 State