新生(Sprout) 方法與類別

16th鐵人賽重構 c#

glj8989332

2024-09-24 23:58:00

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新生方法

重構前

假如有個類別TransactionGate, 用來處理每個交易的日期設定, 並賦予manager做處理.

public class TransactionGate
{
	public void PostEntries(List<Entry> entries)
	{
		foreach(var entry in entries)
		{
			entry.PostDate();
		}
		transactionBundle.GetListManager().Add(entries);
	}
}

此時我們要修改流程, 驗證是否有重複的交易時, 改成這樣

public class TransactionGate
{
	public void PostEntries(List<Entry> entries)
	{
		List<Entry> entriesToAdd = new List<Entry>();
		foreach(var entry in entries)
		{
			if(!transactionBundle.GetListManager().Contains(entry))
			{
				entry.PostDate();
				entriesToAdd.Add(entry);
			}
		}
		transactionBundle.GetListManager().Add(entriesToAdd);
	}
}

重構後

將new List<Entry>()開始的驗證邏輯, 抽成一個新的方法UniqueEntries(函數)來處理.

public class TransactionGate
{
	public void PostEntries(List<Entry> entries)
	{
		List<Entry> entriesToAdd = UniqueEntries(entries) ;
		foreach(var entry in entriesToAdd)
		{
			entry.PostDate();
		}
		transactionBundle.GetListManager().Add(entriesToAdd);
	}
	
	private List<Entry> UniqueEntries(List<Entry> entries)
	{
		List<Entry> result = new List<Entry>();
		foreach(var entry in entries)
		{
			if(!transactionBundle.GetListManager().Contains(entry))
			{
				result.Add(entry);
			}
		}
		
		return result;
	}
}

新生類別

重構前

假如有個類別QuarterlyReportGenerator, 用來產生每季報表:

public class QuarterlyReportGenerator
{
    public string Generate()
    {
        string result = "<html><head>...";
        result += "content";
        result += "content";
        result += "content";
        result += "content";
        result += "content";

        return result;
    }
}

重構後

這時要多新的報表header, 我們將它放在新的類別QuarterlyReportTableHeaderProducer
並放到QuarterlyReportGenerator使用

public class QuarterlyReportTableHeaderProducer
{
    public string MakeHeader()
    {
        return "header....";
    }
}

public class QuarterlyReportGenerator
{
    public string Generate()
    {
        string result = "<html><head>...";
        result += "content";
        result += "content";
        result += "content";
        result += "content";
        result += "content";
        QuarterlyReportTableHeaderProducer producer = new QuarterlyReportTableHeaderProducer();
        result += producer.MakeHeader();

        return result;
    }
}

為了讓概念一致, 讓命名都改成Generate, 也能同時抽出共通的類別或介面

public abstract class HTMLGenerator
{
    public abstract string Generate();
}

public class QuarterlyReportGenerator : HTMLGenerator
{
    public override string Generate()
    {
        string result = "<html><head>...";
        result += "content";
        result += "content";
        result += "content";
        result += "content";
        result += "content";
        HTMLGenerator producer = new QuarterlyReportTableHeaderProducer();
        result += producer.Generate();

        return result;
    }
}

public class QuarterlyReportTableHeaderProducer : HTMLGenerator
{
    public override string Generate()
    {
        return "header....";
    }
}