机房重构---下机（策略模式和职责连模式）

前言：

下机需要查看消费时间以及选择用户类型，因此这里用到了职责连模式以及策略模式两种模式。消费时间用的是职责连模式，选择用户类型（固定用户，临时用户）。涉及多个表的查询，用视图是个不错的选择。

内容：

一、各个层调用关系：

二、UI层代码：

Private Sub btnOffLine_Click(sender As Object, e As EventArgs) Handles btnOffLine.Click
'1、卡号是否存在 2、卡号是否上机，上机记录表
'3、计算消费金额:1、小于（ 最少上机时间和准备时间）2、大于（ 最少上机时间和准备时间）小于递增时间 （临时和固定）
'4、更新上机记录表，卡表

If txtCardNo.Text = "" Then
MsgBox("请输入卡号")
Return
End If
Dim table1 As New DataTable
Dim Card As New Entity.EntityCard
Dim line As New Entity.LineLogEntity
Dim facade As New Facade.OffLineFacade
Dim table2 As New DataTable
Dim basic As New Entity.EntityBasicDataSet

Card.CardNo = txtCardNo.Text()

'查询卡表获取卡类型等
table1 = facade.selectOffF(Card)

'查询基础数据表
table2 = facade.selectBasicF(basic)

Card.type = table1.Rows(0).Item(3)
Card.Balance = table1.Rows(0).Item(2)
line.OnDate = table1.Rows(0).Item(1)
line.OffDate = Format(Now, "yyyy-MM-dd HH:mm:ss")
basic.LeastTime = table2.Rows(0).Item(5)
basic.UnitTime = table2.Rows(0).Item(4)
basic.ReadyTime = table2.Rows(0).Item(6)
basic.tmpRate = table2.Rows(0).Item(3)
basic.Rate = table2.Rows(0).Item(2)

Dim facade2 As New Facade.CashContext
'计算消费时间
line.mins = facade.ConsumeTimeF(basic, Card, line)
'选择卡类型
line.Cash = facade2.SelectType(basic, Card, line)

Card.Balance = CDec(Card.Balance) - CDec(line.Cash)

line.CardNo = Card.CardNo

Dim flag As Boolean
flag = facade.offLine(line, Card)
If flag = True Then
MsgBox("下机成功")
txtCardNo.Text = line.CardNo
txtBalance.Text = Card.Balance
txtType.Text = Card.type
txtStudentNo.Text = table1.Rows(0).Item(5)
txtStudentName.Text = table1.Rows(0).Item(6)
txtDepartment.Text = table1.Rows(0).Item(8)
txtSex.Text = table1.Rows(0).Item(7)
txtOnDate.Text = line.OnDate
txtOffDate.Text = line.OffDate
txtmins.Text = line.mins
txtCash.Text = line.Cash

Else
MsgBox("下机失败")
End If

End Sub

三、外观层

1、职责连查看消费时间

Public Function ConsumeTimeF(ByVal basic As Entity.EntityBasicDataSet, ByVal card As Entity.EntityCard, ByVal line As Entity.LineLogEntity) As Integer
Dim preparetime As New BLL.PrepareTimeBLL(basic)
Dim leasttime As New BLL.LeastTimeBLL(basic)
Dim unittime As New BLL.UintTimeBLL

preparetime.setsuccessor(leasttime)
leasttime.setsuccessor(unittime)

Dim time As Integer
time = DateDiff("n", line.OnDate, line.OffDate)
Return preparetime.TimeRequest(time)

End Function

2、策略模式选择卡类型

Public Class CashContext
Dim cashsuper As CashSuper
'根据策略 不同，采用不同的计费方式
Public Function SelectType(ByVal basic As Entity.EntityBasicDataSet, ByVal card As Entity.EntityCard, ByVal line As Entity.LineLogEntity) As Single
Select Case card.type.Trim()
Case "固定用户"
cashsuper = New FixedUserBLL() '实例化固定用户策略

Case "临时用户"
cashsuper = New TmpUserBLL()
End Select
Return cashsuper.GetConsumMoney(basic, card, line)

End Function

四、BLL层

1、职责连查看消费时间

（1）时间基类

Public MustInherit Class TimeBLL
Property successor As TimeBLL
Public Sub setsuccessor(ByVal successor As TimeBLL) '设置继承类
Me.successor = successor
End Sub
'请求处理的抽象方法
Public MustOverride Function TimeRequest(ByVal time As Integer) As Integer

End Class（2）LeastTimeBLL类
Public Class LeastTimeBLL : Inherits TimeBLL
Protected leastTime As Integer

Public Sub New(ByVal basic As Entity.EntityBasicDataSet)
Me.leastTime = CInt(basic.LeastTime) '将至少上机时间赋值为leastTime
End Sub

Public Overrides Function TimeRequest(time As Integer) As Integer
If time <= leastTime Then '如果上机时间小于至少上机时间，返回至少上机时间
Return leastTime
Else
Return successor.TimeRequest(time)
End If
End Function
End Class（3）PreparetimeBLL类 

Public Class PrepareTimeBLL : Inherits TimeBLL
Dim preparetime As Integer
' Public Sub New是VB.net默认的构造函数  form_load是Form类在调用New构造函数后加载窗体绘图后才调用的方法
Public Sub New(ByVal basic As Entity.EntityBasicDataSet)
Me.preparetime = CInt(basic.ReadyTime)  '传入准备时间
End Sub

Public Overrides Function TimeRequest(time As Integer) As Integer
If time <= preparetime Then '如果上机时间小于准备时间，返回0
Return 0
Else
Return successor.TimeRequest(time)
End If

End Function
End Class

（4）Unittime类
Public Class UintTimeBLL : Inherits TimeBLL

'正常消费
Public Overrides Function TimeRequest(time As Integer) As Integer
Return time
End Function
End Class

2、策略模式选择卡类型：

（1）固定用户

Public Class FixedUserBLL : Inherits CashSuper
'固定用户
Dim fixedRate As Single
Public Overrides Function GetConsumMoney(ByVal basic As Entity.EntityBasicDataSet, ByVal card As Entity.EntityCard, ByVal line As Entity.LineLogEntity) As Single
fixedRate = Trim(Int(basic.Rate))
Dim consumMoney As Single
consumMoney = Trim(CSng(fixedRate) * CSng(line.mins * 1.0 / 60.0))
If consumMoney < Trim(Int(basic.Rate)) Then
consumMoney = Int(basic.Rate)
End If
Return consumMoney

End Function
End Class（2）临时用户
Public Class TmpUserBLL : Inherits CashSuper '临时用户

Dim TmpRate As Single
Public Overrides Function GetConsumMoney(basic As Entity.EntityBasicDataSet, card As Entity.EntityCard, line As Entity.LineLogEntity) As Single
TmpRate = basic.tmpRate
Dim consumMoney As Single
consumMoney = Trim(CSng(TmpRate) * CSng(line.mins * 1.0 / 60.0))
If consumMoney < Int(basic.tmpRate) Then
consumMoney = Int(basic.tmpRate)
End If
Return consumMoney
End Function
End Class

五、DAL层

Public Class AdcountDAL : Implements IDAL.IAdcount

Public Function update(adcount As EntityAdCount) As Integer Implements IAdcount.update
Dim sql As String
Dim sqlhelper As New SQLHelper.sqlhelper
Dim flag As Integer

Dim paras As SqlParameter() = {New SqlParameter("@UserID", adcount.UserID),
New SqlParameter("@CancelCash", adcount.CancelCash),
New SqlParameter("@CheckCash", adcount.CheckCash),
New SqlParameter("@RechCash", adcount.RechCash),
New SqlParameter("@Checkdate", adcount.Checkdate)}

sql = "proc_Account"

flag = sqlhelper.ExecAddDelUpdate(sql, CommandType.StoredProcedure, paras)

Return flag

End Function
End Class存储过程：
ALTER PROCEDURE [dbo].[pro_Offline]
@CardNO varchar(20),
@OffDate datetime,
@mins int,
@Cash numeric(10, 2),
@state varchar(20),
@Balance numeric(10, 2)
AS
BEGIN

update Y_LineLog_Info set OffDate=@OffDate ,mins =@mins ,Cash=@Cash ,state=@state where CardNo =@CardNO
update Y_Card_Info set Balance=Balance where CardNo =@CardNO

END

总结：

下机用到了两个设计模式，其实设计到哪部分特别复杂就该考虑用设计模式去解耦合，设计模式还需要我们继续去研究。