Question

Velocity是否支持服务器端原子更新？我正在尝试查看是否可以移植一些基于memcache的INCR操作实现环形缓冲区的代码（基于memcached）。

Answer 1

我不能说我对memcached足够熟悉完全你的意思，但我假设它涉及锁定一个缓存的项目，以便一个客户端可以更新它， Velocity通过GetAndLock和PutAndUnlock方法支持。

编辑：好的，现在我理解你的意思，不，我没有在Velocity中看到过类似的东西。但你可以把它写成一个扩展方法，例如

Imports System.Runtime.CompilerServices

Public Module VelocityExtensions

<Extension()> _
Public Sub Increment(ByVal cache As Microsoft.Data.Caching.DataCache, ByVal itemKey As String)

    Dim cachedInteger As Integer
    Dim cacheLockHandle As DataCacheLockHandle

    cachedInteger = DirectCast(cache.GetAndLock(itemKey, New TimeSpan(0, 0, 5), cacheLockHandle), Integer)

    cachedInteger += 1

    cache.PutAndUnlock(itemKey, cachedInteger, cacheLockHandle)

End Sub

<Extension()> _
Public Sub Decrement(ByVal cache As Microsoft.Data.Caching.DataCache, ByVal itemKey As String)

    Dim cachedInteger As Integer
    Dim cacheLockHandle As DataCacheLockHandle

    cachedInteger = DirectCast(cache.GetAndLock(itemKey, New TimeSpan(0, 0, 5), cacheLockHandle), Integer)

    cachedInteger -= 1

    cache.PutAndUnlock(itemKey, cachedInteger, cacheLockHandle)

End Sub

End Module

您的使用将成为：

Imports VelocityExtensions
Imports Microsoft.Data.Caching

Partial Public Class _Default
Inherits System.Web.UI.Page

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    Dim myCache As DataCache
    Dim factory As DataCacheFactory

    myCache = factory.GetCache("MyCacheName")

    myCache.Increment("MyInteger")

End Sub

End Class

MS Velocity中的原子更新

1 个答案: