behavior_state

状態者モード
本章タスク
1.状態者モードの定義
 
ステータス者モード:異なるステータス、異なる動作;あるいは、それぞれの状態に相応の行為がある.
2.我々は常にIf elseif elseを使用して状態切り替えを行い、状態の切り替えが繰り返されることを解決する.
eg:「hello」-->「hi」-->「bye」-->「hello」の配列の組合せ
 

package com.aptech.behavior.state;

/**
 * 
 *    : IShopState.java
 *   ：    
 *   :     --         (    ,    ,    )
 *        "hello"-->"hi"-->"bye"-->"hello"       ,
 *         State  ,  State         ,   ,
 *              :             ,
 *         ,   State .
 * Email:[email protected]
 *     ： 2010-7-9  08:07:46
 */
public interface IShopState {
	  //    
    public void shop();
    //    
    public void generateBill();
    //    
    public void pay();
}

 

package com.aptech.behavior.state;

/**
 * 
 *    : ShopState.java
 *   ：   
 *   :The parent class of state
 * Email:[email protected]
 *     ： 2010-7-9  08:57:50
 */
public class ShopState implements IShopState {
	
	public ShopState() {
	}
	
	public void shop() {
	}
	
	public void generateBill() {
	}
	
	public void pay() {
	}

	/**
	 * 
	 * 〈     〉
	 * 
	 * @param [ShopContext] [        ]
	 * @param [ShopState] [        ]
	 * @return [void]
	 * @Author   
	 *         Email:[email protected]
	 */
	protected void changeState(ShopContext c, ShopState s) {
		c.changeState(s);
	}
}

 

package com.aptech.behavior.state;

/**
 * 
 *    : ShopContext.java
 *   ：    
 *   :          
 * Email:[email protected]
 *     ： 2010-7-9  09:07:10
 */
public class ShopContext {
	
	//       
	private ShopState	currentState;
	
	public ShopContext() {
	}
	
	/**
	 * 
	 * 〈     〉
	 * @param [ShopState]     [       ]
	 * @return  [void]
	 * @Author   
	 * Email:[email protected]
	 */
	public void changeState(ShopState s) {
		currentState = s;
	}
	public void shop() {
		currentState.shop();
	}
	public void generateBill() {
		currentState.generateBill();
	}
	public void pay() {
		currentState.pay();
	}
}

 

package com.aptech.behavior.state;

/**
 * 
 *    : Shop.java 
 *   ：    
 *   :        
 * Email:[email protected] 
 *     ：2010-7-9  08:52:11
 */
public class Shop extends ShopState {
    public static boolean instanceFlag = false; //true if have 1 instance
    private Shop() {
    }
    public static Shop getInstance() {
        if(! instanceFlag) {
            instanceFlag = true;
            return new Shop();
        }
        return null;
    }
    @Override
		public void shop() {
        System.out.println("The state is shopping now !");
    }
}

 

package com.aptech.behavior.state;

/**
 * 
 *    : GenerateBill.java
 *   ：    
 *   :        
 * Email:[email protected]
 *     ： 2010-7-9  08:55:34
 */
public class GenerateBill extends ShopState {
	public static boolean	instanceFlag	= false;	// true if have 1 instance
	private GenerateBill() {
	}
	public static GenerateBill getInstance() {
		if (!instanceFlag) {
			instanceFlag = true;
			return new GenerateBill();
		}
		return null;
	}
	public void generateBill() {
		System.out.println("The state is generating bill now !");
	}
}

 

package com.aptech.behavior.state;
/**
 * 
 *    : Pay.java
 *   ：    
 *   :      
 * Email:[email protected]
 *     ： 2010-7-9  08:16:15
 */
public class Pay extends ShopState {
    public static boolean instanceFlag = false; //true if have 1 instance
    private Pay() {
    }
    public static Pay getInstance() {
        if(! instanceFlag) {
            instanceFlag = true;
            return new Pay();
        }
        return null;
    }
    public void pay() {
        System.out.println("The state is pay now !");
    }
}

 

package com.aptech.behavior.state;

import junit.framework.TestCase;

public class StateTest extends TestCase {

	protected void setUp() throws Exception {
		super.setUp();
	}

	public void testState(){
		
		//           
		ShopContext myContext = new ShopContext();
		
		//      
		ShopState myShop = Shop.getInstance();
		ShopState myGenBill = GenerateBill.getInstance();
		ShopState myPay = Pay.getInstance();

		//       
		myContext.changeState(myShop);
		myContext.shop();
		
	  //       
		myContext.changeState(myGenBill);
		myContext.generateBill();
		
		//       
		myContext.changeState(myPay);
		myContext.pay();
	}
}

  
本章の目標
1.状態者パターンの理解