AFDataCache Class

Public NotInheritable Class AFDataCache
	Implements IDisposable, IAFDataProvider

Dim instance As AFDataCache

public ref class AFDataCache sealed : IDisposable, 
	IAFDataProvider

[<SealedAttribute>]
type AFDataCache =  
    class
        interface IDisposable
        interface IAFDataProvider
    end

' This example demonstrates how to create the DataReference configuration
' for all attributes with a PIPoint DataReference.

' Get the Database
Dim myPISystems As New PISystems
Dim myPISystem As PISystem = myPISystems.DefaultPISystem
Dim myDB As AFDatabase = myPISystem.Databases.DefaultDatabase
Dim inputValue1 As AFValue
Dim inputValue2 As AFValue
Dim numEventsCached0 As Long = 0
Dim numEventsProcessed0 As Long = 0
Dim numEventsCached1 As Long = 0
Dim numEventsProcessed1 As Long = 0
Dim numEventsCached2 As Long = 0
Dim numEventsProcessed2 As Long = 0
Dim numHitCount As Long = 0
Dim numMissedHitCount As Long = 0

' Create an Element with an Attribute
Dim myElement As AFElement = myDB.Elements.Add("MyElement*")
Dim myAttribute1 As AFAttribute = myElement.Attributes.Add("MyAttribute1")
Dim myAttribute2 As AFAttribute = myElement.Attributes.Add("MyAttribute2")

' Create PIPoints to Update
Dim piServer As PIServer = PIServers.GetPIServers().DefaultPIServer
Dim point As PIPoint = Nothing
If (Not PIPoint.TryFindPIPoint(piServer, "testfloat1", point)) Then
    point = piServer.CreatePIPoint("testfloat1", Nothing)
End If

If (Not PIPoint.TryFindPIPoint(piServer, "testfloat2", point)) Then
    point = piServer.CreatePIPoint("testfloat2", Nothing)
End If

myAttribute1.DefaultUOM = myPISystem.UOMDatabase.UOMs("kelvin")
myAttribute1.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem)
myAttribute1.ConfigString = "\\%Server%\testfloat1;ReadOnly=false"

myAttribute2.DefaultUOM = myPISystem.UOMDatabase.UOMs("kelvin")
myAttribute2.DataReferencePlugIn = AFDataReference.GetPIPointDataReference(myPISystem)
myAttribute2.ConfigString = "\\%Server%\testfloat2;ReadOnly=false"

' Send some values to tags to initialize them
For i As Integer = 1 To 2 Step 1
    Dim tmptime As AFTime = New AFTime("*")
    inputValue1 = New AFValue(5 * i, tmptime)
    inputValue2 = New AFValue(10 * i, tmptime)
    myAttribute1.SetValue(inputValue1)
    myAttribute2.SetValue(inputValue2)
    Thread.Sleep(1000)
Next

' Sleep for a minute
Thread.Sleep(60000)

' Create data cache object and sign up the attributes for the cache
Dim myAFDataCache As AFDataCache = New AFDataCache(1000)
Dim addResult As AFKeyedResults(Of AFAttribute, AFData) = myAFDataCache.Add(myElement.Attributes)

numEventsCached0 = myAFDataCache.EventsCached
numEventsProcessed0 = myAFDataCache.EventsProcessed

'Cache only last minute worth of data
myAFDataCache.CacheTimeSpan = New TimeSpan(0, 1, 0)

' Send values to tags
For i As Integer = 1 To 10 Step 1
    Dim tmptime As AFTime = New AFTime("*")
    inputValue1 = New AFValue(5 * i, tmptime)
    inputValue2 = New AFValue(10 * i, tmptime)
    myAttribute1.SetValue(inputValue1)
    myAttribute2.SetValue(inputValue2)
    Thread.Sleep(1000)
Next

' Get data for cache
' Sleep a little to make sure all events get through update manager
Thread.Sleep(100)
myAFDataCache.UpdateData()

numEventsCached1 = myAFDataCache.EventsCached
numEventsProcessed1 = myAFDataCache.EventsProcessed

' Sleep for a minute
Thread.Sleep(60000)

' Send values to tags after a minute so that these events replace the old ones
For i As Integer = 1 To 10 Step 1
    Dim tmptime As AFTime = New AFTime("*")
    inputValue1 = New AFValue(5 * i, tmptime)
    inputValue2 = New AFValue(10 * i, tmptime)
    myAttribute1.SetValue(inputValue1)
    myAttribute2.SetValue(inputValue2)
    Thread.Sleep(1000)
Next

' Get data for cache
Thread.Sleep(100)
myAFDataCache.UpdateData()

numEventsCached2 = myAFDataCache.EventsCached
numEventsProcessed2 = myAFDataCache.EventsProcessed

Dim numInterpolatedCalls As Integer = 100

If (Not addResult.HasErrors) Then
    Dim tmpData1 As AFData = myAttribute1.Data
    Dim tmpTime As AFTime = New AFTime("*-30s")

    ' Call made to regular Data object so therefore cache not used
    For i As Integer = 1 To numInterpolatedCalls Step 1
        tmpData1.InterpolatedValue(tmpTime, Nothing)
    Next i

    Dim tmpData2 As AFData = addResult(myAttribute1)

    ' Call made to cache Data object so cache is used
    For i As Integer = 1 To numInterpolatedCalls Step 1
        tmpData2.InterpolatedValue(tmpTime, Nothing)
    Next i

    numHitCount = myAFDataCache.CacheHitCount

    ' Call made to a time period not covered by the cache and therefore missed hit count should increment by numInterpolatedCalls
    Dim tmpTimediff As AFTime = New AFTime(addResult(myAttribute1).CacheStartTime.UtcSeconds - 2)
    For i As Integer = 1 To numInterpolatedCalls Step 1
        tmpData2.InterpolatedValue(tmpTimediff, Nothing)
    Next i
    numMissedHitCount = myAFDataCache.MissedHitCount
End If

No code example is currently available or this language may not be supported.

No code example is currently available or this language may not be supported.