java设计模式_命令模式

 1.抽象出待执行的动作以参数化某对象。

 2.在不同的时刻指定、排列和执行请求。

 3.支持取消操作。

 4.支持修改日志，这样当系统崩溃时，这*修改可以被重做一遍。

 5.用构建在原语操作上的高层操作构造一个系统。

Command模式可应用于

a）整个调用过程比较繁杂，或者存在多处这种调用。这时，使用Command类对该调用加以封装，便于功能的再利用。
b）调用前后需要对调用参数进行某些处理。

c）调用前后需要进行某些额外处理，比如日志，缓存，记录历史操作等。

http://www.cnblogs.com/devinzhang/archive/2012/01/06/2315235.html

package com.wangbiao.command;

import java.math.BigDecimal;

public class Client {

	public static void main(String[] args) {
		
		//receiver
		Project project=new Project("中国人民银行在线支付系统",new BigDecimal(5000000),new BigDecimal(1000000));
		
		//Command
		Command development=new DevelopmentCheck(project);
		Command finacial=new FinancialCheck(project);
		Command market=new MarketCheck(project);
		Company company=new Company(market,development,finacial);
		
		//invoker
		
		company.check_project();
		
		
		
		
	}
	
}

package com.wangbiao.command;

public interface Command {
	

	//undo
	public void command_undo();
	
	//check
	public void check_project();
}

package com.wangbiao.command;

public class Company {

	private Command marketCheck,developmentCheck,finacialCheck;
	
	public Company() {
		
	}
	
	public Company(Command marketCheck,Command developmentCheck,Command finacialCheck) {
		this.marketCheck=marketCheck;
		this.developmentCheck=developmentCheck;
		this.finacialCheck=finacialCheck;
	}
	
	public void check_project(){
		this.marketCheck.check_project();
		this.developmentCheck.check_project();
		this.finacialCheck.check_project();
	}
	
	
}

package com.wangbiao.command;


public class DevelopmentCheck implements Command{
	
	private Project project;
	
	public DevelopmentCheck() {
		
	}
	
	public DevelopmentCheck(Project project) {
		this.project=project;
	}
	

	@Override
	public void command_undo() {
		
	}

	@Override
	public void check_project() {
		System.out.println("Development department begin to check.");
		System.err.println("Development Department: "+this.project.show_project_detail_info());
		System.out.println("Development Department: "+this.project.show_project_detail_info());
		System.out.println("Development department end check.");
	}

	

}

package com.wangbiao.command;


public class FinancialCheck implements Command{

	private Project project;
	
	public FinancialCheck() {
		// TODO Auto-generated constructor stub
	}
	
	public FinancialCheck(Project project) {
		 this.project=project;
	}
	


	@Override
	public void command_undo() {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void check_project() {
		System.out.println("Financial department begin to check.");
		System.err.println("Financial Department: "+this.project.show_project_detail_info());
		System.out.println("Financial Department: "+this.project.show_project_detail_info());
		System.out.println("Financial department end check.");
		
	}

	

}

package com.wangbiao.command;


public class MarketCheck implements Command {
	private Project project;

	public MarketCheck() {
		
	}
	public MarketCheck(Project project) {
		this.project=project;
	}
	
	@Override
	public void command_undo() {
		
	}

	@Override
	public void check_project() {
		System.out.println("Market department begin to check.");
		System.err.println("Market Department: "+this.project.show_project_detail_info());
		System.out.println("Market Department: "+this.project.show_project_detail_info());
		System.out.println("Market department end check.");
	}
	

}

package com.wangbiao.command;

import java.math.BigDecimal;

public class Project {

	private String f_name;
	private BigDecimal f_cost;
	private BigDecimal f_profit;
	
	public Project() {
		
	}
	
	public Project(String f_name,BigDecimal f_cost,BigDecimal f_profit) {
		this.f_name=f_name;
		this.f_cost=f_cost;
		this.f_profit=f_profit;
	}
	
	public String show_project_detail_info(){
		
		return "项目名称： "+f_name+"-"+" 项目成本： "+f_cost+"-"+" 项目利润： "+f_profit;
		
	}
}