"Model" method is boundless-policy mode + simple factory to achieve off-site Charging

Fees are charged for downloading. Temporary users and students are charged for downloading. This gives me the idea of using the Policy mode and choosing a specific algorithm based on whether it is a temporary user or a student, this is a simple factory. Well, it's a simple factory + A policy model to realize the off-site charging.

Policy-encapsulate specific policies

'Encapsulate a specific algorithm. You need to reference an algorithm. Public class consumecontext Dim strategyconsume as consume   Sub new (byref strategy as consume) Me. strategyconsume = strategy End sub   Public Function contextinterface () as double   Return strategyconsume. getconsume () End Function   End Class

Algorithm parent class-Provides override methods and public members

Public class consume   Protected line as lineinfo Protected consumemoney as double Protected chargestandard as chargestandardinfo Protected count as int16   Public overridable function getconsume () as double   End Function End Class

 

Algorithm

Public class tempconsume   Inherits consume   Sub new (byref line as lineinfo, byref chargestandard as chargestandardinfo) Me. Line = line   Me. chargestandard = chargestandard End sub   Public overrides function getconsume () as double   If line. consumetime Mod (convert. toint16 (chargestandard. unittime) <> 0 then Consumemoney = (line. consumetime \ chargestandard. unittime + 1) * chargestandard. tempcharge Else Consumemoney = (line. consumetime \ chargestandard. unittime) * chargestandard. tempcharge End if   Return consumemoney   End Function   End Class

 

Algorithm B

Public class fixcomsume   Inherits consume   Sub new (byref line as lineinfo, byref chargestandard as chargestandardinfo) Me. Line = line   Me. chargestandard = chargestandard End sub   Public overrides function getconsume () as double   If line. consumetime Mod (convert. toint16 (chargestandard. unittime) <> 0 then Consumemoney = (line. consumetime \ chargestandard. unittime + 1) * chargestandard. fixcharge Else Consumemoney = (line. consumetime \ chargestandard. unittime) * chargestandard. fixcharge End if   Return consumemoney End Function   End Class

 

Client code

'Get the charge amount. Although it is placed on layer B, it is equivalent to the client code Public Function getconsume (byref member as studentinfo, byref line as lineinfo, byref chargestandard as chargestandardinfo) as double   Select case Member. isonline   Case "true"   Dim stragey as new fixcomsume (line, chargestandard)   Dim cashcontext as new consumecontext (stragey)   Return cashcontext. contextinterface ()   Case "false"   Dim stragey as new tempconsume (line, chargestandard)   Dim cashcontext as new consumecontext (stragey)   Return cashcontext. contextinterface ()   End select   End Function   End Class

 

In my opinion, the design pattern is a very big thing, "You can only watch and never play". This time, when other students use it, I also tried to use the design mode (although the most simple one). I think the design mode can also be very grounded. You can use it boldly!