.net模式开发学习－管道过滤器模式

简单举例如下:

会员搜索过滤模块,要先按姓名搜索,再按编号过滤部分会员.

例子比较简单,按姓名搜索,过滤会员在.两功能上是独立的.

没有依赖性,不过实际中常用来功能有依赖性解决并行开发的.

例子中简单只有一个数据源.实际中常常是用来处理两个数据源.

第一个是作为输入的,第二个则是作为输出的.

谁有更好的理解和应用?

using System;

using System.Collections.Generic;

using System.Text;

using System.Data;

namespace ModeStudy.Pipes_and_Filters

{

//可用的流动处理数据接口

public interface IEnableStreamingProcessData<DataSource>

{

//例子简单只有一个数据源.

//实际中常常会是两个数据源.第一个作为,第二个作为输出.

//记得Java中的过滤器吗?

//public void doFilter(ServletRequest req, ServletResponse res, FilterChain fc)

//void Process(DataSourceInput dataInput,out DataSourceOutput dataOutput)

void Process(ref DataSource dataSource);

}

//链条式处理类

public class ProcessChain<DataSource> where DataSource : new()

{

private LinkedList<IEnableStreamingProcessData<DataSource>> _links = new LinkedList<IEnableStreamingProcessData<DataSource>>();

public void AddLink(LinkedListNode<IEnableStreamingProcessData<DataSource>> link)

{

_links.AddLast(link);

}

public void Process(ref DataSource dataSource)

{

foreach (IEnableStreamingProcessData<DataSource> element in _links)

{

element.Process(ref dataSource);

}

}

}

//搜索会员类

public class MembersSearch : IEnableStreamingProcessData<DataTable>

{

private string _searchName;

public string SearchName

{

get { return _searchName; }

set { _searchName = value; }

}

public MembersSearch()

{

this.Reset();

}

public void Reset()

{

_searchName = string.Empty;

}

#region IEnableStreamingProcessData<DataTable> 成员

public void Process(ref DataTable dataSource)

{

dataSource.DefaultView.RowFilter = "name like '%" + this.SearchName+"%'";

dataSource = dataSource.DefaultView.ToTable();

}

#endregion

}

//会员过滤类

public class MembersFilter : IEnableStreamingProcessData<DataTable>

{

private int _id;

public int FilterID

{

get { return _id; }

set { _id = value; }

}

public MembersFilter()

{

this.Reset();

}

public void Reset()

{

_id = -1;

}

#region IEnableStreamingProcessData<DataTable> 成员

public void Process(ref DataTable dataSource)

{

dataSource.DefaultView.RowFilter = "id <>" + this.FilterID.ToString();

dataSource = dataSource.DefaultView.ToTable();

}

#endregion

}

//会员搜索单例工厂

public static class MemberSearchFactory

{

private static MembersSearch memSearch;

private static MembersFilter memFilter;

public static IEnableStreamingProcessData<DataTable> MemberSearchInstance(string searchName)

{

if (null == memSearch)

memSearch = new MembersSearch();

memSearch.Reset();

memSearch.SearchName = searchName;

return memSearch;

}

public static IEnableStreamingProcessData<DataTable> MemberFilterInstance(int filterID)

{

if (null == memFilter)

memFilter = new MembersFilter();

memFilter.Reset();

memFilter.FilterID = filterID;

return memFilter;

}

}

public class Test

{

public void Process()

{

//构造一个具有 id, name列的DataTable.,并添加三条数据.

DataTable table = new DataTable();

DataColumnCollection columns = table.Columns;

columns.Add(new DataColumn("id",typeof(int)));

columns.Add(new DataColumn("name",typeof(string)));

DataRow row = table.NewRow();

row["id"]=1;

row["name"]="tyweber";

table.Rows.Add(row);

row = table.NewRow();

row["id"] = 2;

row["name"] = "admin";

table.Rows.Add(row);

row = table.NewRow();

row["id"] = 3;

row["name"] = "tyweber_zouyong";

table.Rows.Add(row);

//实例化链条处理类,进行筛选DataTable中的数据.

ProcessChain<DataTable> chain = new ProcessChain<DataTable>();

IEnableStreamingProcessData<DataTable> memSearch = MemberSearchFactory.MemberSearchInstance("tyweber");

IEnableStreamingProcessData<DataTable> memFilter = MemberSearchFactory.MemberFilterInstance(1);

LinkedListNode<IEnableStreamingProcessData<DataTable>> nodeSearch = new LinkedListNode<IEnableStreamingProcessData<DataTable>>(

memSearch

);

LinkedListNode<IEnableStreamingProcessData<DataTable>> nodeFilter = new LinkedListNode<IEnableStreamingProcessData<DataTable>>(

memFilter

);

chain.AddLink(nodeSearch);

chain.AddLink(nodeFilter);

chain.Process(ref table);

foreach (DataRow r in table.Rows)

{

Console.WriteLine(r["name"]);

}

}

}

}