java设计模式--[结构模式]--门面模式[decorator pattern]

 一. 門面模式

     門面模式,又叫外觀模式,一個大的系統由若干個子系統構成,每個子系統中包含多個類,這些類協同合作為用戶提供所需要的功能,若直接和子類進行交互,則就形成了依賴關係,門面模式就是用來解決此問題的一個成熟模式.

二. 門面模式的UML類圖如下所示:
     
 

三. 現在用一個郵局的物流系統來模擬這個門面模式的實現,完整示例代碼如下:

1. 物流接口類

package structuralPattern.facade.facade1;
/**
 * @ClassName: ILogistics 
 * @Description:物流接口
 * @author Liyongbin
 * @date 2011-2-9 上午11:20:48 
 * @version V1.0
 */
public interface ILogistics {
	//發貨
	public ILogistics sub_send();
	//收貨
	//public ILogistics sub_receive();
}

2. 郵局類

package structuralPattern.facade.facade1;
/**
 * @ClassName: Postoffice 
 * @Description:郵局類
 * @author Liyongbin
 * @date 2011-2-9 上午11:21:31 
 * @version V1.0
 */
public class Postoffice implements ILogistics{
	
	//
	private Sub_measurement measurement;
	private Sub_package packaging;
	private Sub_weighIn weighIn;
	private Sub_countPrice countprice;
	private Sub_mailing miling;
	
	//無參構造器
	public Postoffice() {
		super();
	}
	//構造器
	public Postoffice(Sub_measurement measurement, Sub_weighIn weighIn, Sub_package packaging,
			Sub_countPrice countprice, Sub_mailing amiling) {
		super();
		this.measurement = measurement;
		this.weighIn = weighIn;
		this.packaging = packaging;
		this.countprice = countprice;
		this.miling = amiling;
	}
	//運送物品
	@Override
	public ILogistics sub_send() {
		packaging.packaging();
		measurement.measurement();
		weighIn.weighIn();
		countprice.countPrice();
		miling.mailing();
		return null;
	}
}

3. 物品打包類

package structuralPattern.facade.facade1;
/**
 * @ClassName: Sub_package 
 * @Description:物品打包
 * @author Liyongbin
 * @date 2011-2-9 上午11:34:16 
 * @version V1.0
 */
public class Sub_package {
	public void packaging(){
		System.out.println("流程開始");
		System.out.println("包裝物品...");
	}
}

4. 量物品體積

package structuralPattern.facade.facade1;
/**
 * @ClassName: Sub_measurement 
 * @Description:量物品體積
 * @author Liyongbin
 * @date 2011-2-9 上午11:32:56 
 * @version V1.0
 */
public class Sub_measurement {
	public void measurement(){
		System.out.println("測量物品體積...");
	}
}

5. 物品稱重

package structuralPattern.facade.facade1;
/**
 * @ClassName: Sub_weighIn 
 * @Description:物品稱重
 * @author Liyongbin
 * @date 2011-2-9 上午11:31:29 
 * @version V1.0
 */
public class Sub_weighIn {
	public void weighIn(){
		System.out.println("稱物品重量...");
	}
}

6. 投遞物品

package structuralPattern.facade.facade1;
/**
 * @ClassName: Sub_mailing 
 * @Description:投遞物品
 * @author Liyongbin
 * @date 2011-2-9 上午11:38:43 
 * @version V1.0
 */
public class Sub_mailing {
	public void mailing(){
		System.out.println("投遞物品...");
		System.out.println("流程結束");
	}
}

7. 測試類

package structuralPattern.facade.facade1;
/**
 * @ClassName: FacadeTest 
 * @Description: 門面測試類
 * @author Liyongbin
 * @date 2011-2-9 上午11:55:25 
 * @version V1.0
 */
public class FacadeTest {
	public static void main(String[] args) {
		
		//實例化組件
		 Sub_measurement measurement = new Sub_measurement();
		 Sub_package packaging=new Sub_package();
		 Sub_weighIn weighIn= new Sub_weighIn();
		 Sub_countPrice countprice =new Sub_countPrice();
		 Sub_mailing miling =new Sub_mailing();
		 
		//實例化郵局
		ILogistics lt= new Postoffice(measurement,weighIn,packaging,countprice,miling);
		//郵寄物品
		lt.sub_send();
	}
}

8. 運行結果如下: