设计模式
分类:
IT文章
•
2025-01-20 18:37:43
责任链模式适用的场景：
根据这段时间工作中代码重构的经验，我总结出，设计模式中的责任链模式，特别适合重构很长的if-else结构或者很长的switch-case结构的代码。
使用责任链模式对上述情景的代码进行重构后，会带来一下几个好处。
1，首先，很长的if-else结构或很长switch-case结构不见了，取而代之的是直接把处理情景交给一个责任链即可，代码十分简洁。
2，之前每个分支的代码，在责任链模式中，会被分布放到不同的处理类中。虽然类的个数不算少，但每个类的指责十分单一，便于维护。
在代码开发过程中，如果发现自己正在写很长的if-else代码或很长的switch-case代码时，不妨应用一下责任链模式。
以费控的控制模式举例：
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using System;
using ChainOfResponsibility.Structural;
namespace ChainOfResponsibility
{
class Program
{
static void Main(string[] args)
{
int type = new Random().Next(1, 4);
BudgetCalculation bc1 = new YearCumulativeCalculation();
BudgetCalculation bc2 = new QuarterlyCumulativeCalculation();
BudgetCalculation bc3 = new QuarterlyNonCumulativeCalculation();
BudgetCalculation bc4 = new NoControlCalculation();
//此处可以无限扩展控制类型
bc1.SetNextSuccessor(bc2);
bc2.SetNextSuccessor(bc3);
bc3.SetNextSuccessor(bc4);
decimal remaindBudget = 0;
bool result = bc1.BudgetCalculationRequest(type, DateTime.Now, "1.1.1", 400, ref remaindBudget);
}
}
}
Main 入口
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using System;
using System.Collections.Generic;
using System.Text;
namespace ChainOfResponsibility.Structural
{
public enum TypeOfControl
{
/// <summary>
/// 年度累计
/// </summary>
YearCumulative = 1,
/// <summary>
/// 年度非累计
/// </summary>
YearNonCumulative = 2,
/// <summary>
/// 季度累计
/// </summary>
QuarterlyCumulative = 3,
/// <summary>
/// 季度非累计
/// </summary>
QuarterlyNonCumulative = 4,
/// <summary>
/// 月度累计
/// </summary>
MonthCumulative = 5,
/// <summary>
/// 月度非累计
/// </summary>
MonthNonCumulative = 6,
/// <summary>
/// 不控
/// </summary>
NoControl = 99,
}
}
控制类型枚举
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using System;
using System.Collections.Generic;
using System.Text;
namespace ChainOfResponsibility.Structural
{
/// <summary>
/// 预算占用情况基类
/// </summary>
public abstract class BudgetCalculation
{
protected BudgetCalculation successor;
public void SetNextSuccessor(BudgetCalculation successor)
{
this.successor = successor;
}
public abstract bool BudgetCalculationRequest(int type, DateTime budgetTime, string budgetItemCode, decimal applyAmount, ref decimal remaindBudget);
}
/// <summary>
/// 季度累计强控
/// </summary>
public class QuarterlyCumulativeCalculation : BudgetCalculation
{
public override bool BudgetCalculationRequest(int type, DateTime budgetTime, string budgetItemCode, decimal applyAmount, ref decimal remaindBudget)
{
remaindBudget = 0;
if (type == (int)TypeOfControl.QuarterlyCumulative)
{
DateTime begin = new DateTime(2019, 1, 1);
DateTime end = new DateTime(2019, 6, 30);
remaindBudget = 10000;
return remaindBudget > applyAmount;
}
else if (successor != null)
{
return successor.BudgetCalculationRequest(type, budgetTime, budgetItemCode, applyAmount, ref remaindBudget);
}
else
{
throw new NotImplementedException("未实现的方法");
}
}
}
/// <summary>
/// 季度非累计强控
/// </summary>
public class QuarterlyNonCumulativeCalculation : BudgetCalculation
{
public override bool BudgetCalculationRequest(int type, DateTime budgetTime, string budgetItemCode, decimal applyAmount, ref decimal remaindBudget)
{
remaindBudget = 0;
if (type == (int)TypeOfControl.QuarterlyNonCumulative)
{
DateTime begin = new DateTime(2019, 4, 1);
DateTime end = new DateTime(2019, 6, 30);
remaindBudget = 100;
return remaindBudget > applyAmount;
}
else if (successor != null)
{
return successor.BudgetCalculationRequest(type, budgetTime, budgetItemCode, applyAmount, ref remaindBudget);
}
else
{
throw new NotImplementedException("未实现的方法");
}
}
}
/// <summary>
/// 年度累计强控
/// </summary>
public class YearCumulativeCalculation : BudgetCalculation
{
public override bool BudgetCalculationRequest(int type, DateTime budgetTime, string budgetItemCode, decimal applyAmount, ref decimal remaindBudget)
{
remaindBudget = 0;
if (type == (int)TypeOfControl.YearCumulative)
{
DateTime begin = new DateTime(2019, 4, 1);
DateTime end = new DateTime(2019, 6, 30);
remaindBudget = 100;
return remaindBudget > applyAmount;
}
else if (successor != null)
{
return successor.BudgetCalculationRequest(type, budgetTime, budgetItemCode, applyAmount, ref remaindBudget);
}
else
{
throw new NotImplementedException("未实现的方法");
}
}
}
/// <summary>
/// 不控
/// </summary>
public class NoControlCalculation : BudgetCalculation
{
public override bool BudgetCalculationRequest(int type, DateTime budgetTime, string budgetItemCode, decimal applyAmount, ref decimal remaindBudget)
{
remaindBudget = 0;
if (type == (int)TypeOfControl.NoControl)
{
return true;
}
else if (successor != null)
{
return successor.BudgetCalculationRequest(type, budgetTime, budgetItemCode, applyAmount, ref remaindBudget);
}
else
{
throw new NotImplementedException("未实现的方法");
}
}
}
}
