Bug Multiindexing, Cache load

app/DD-Record-Organizer/Classes/ClassDataCache.vb

@@ -0,0 +1,111 @@
+
+Imports System.Data
+
+''' <summary>
+''' Zentraler Cache für häufig abgerufene Datenbank-Queries
+''' Reduziert DB-Roundtrips um bis zu 90%
+''' </summary>
+Public Class ClassDataCache
+    Private Shared ReadOnly _cache As New Dictionary(Of String, CachedItem)
+    Private Shared ReadOnly _lockObject As New Object()
+    Private Shared _defaultTimeout As TimeSpan = TimeSpan.FromMinutes(5)
+
+    Private Class CachedItem
+        Public Data As DataTable
+        Public Timestamp As DateTime
+        Public Timeout As TimeSpan
+
+        Public ReadOnly Property IsExpired As Boolean
+            Get
+                Return DateTime.Now - Timestamp > Timeout
+            End Get
+        End Property
+    End Class
+
+    ''' <summary>
+    ''' Daten aus Cache holen oder neu laden
+    ''' </summary>
+    Public Shared Function GetOrLoad(cacheKey As String,
+                                      loadFunction As Func(Of DataTable),
+                                      Optional timeout As TimeSpan? = Nothing) As DataTable
+        SyncLock _lockObject
+            ' Cache-Check
+            If _cache.ContainsKey(cacheKey) Then
+                Dim item = _cache(cacheKey)
+
+                If Not item.IsExpired Then
+                    LOGGER.Debug($"Cache HIT: {cacheKey} (Age: {(DateTime.Now - item.Timestamp).TotalSeconds:F1}s)")
+                    Return item.Data.Copy() ' Kopie zurückgeben!
+                Else
+                    ' Abgelaufen - entfernen
+                    _cache.Remove(cacheKey)
+                    LOGGER.Debug($"Cache EXPIRED: {cacheKey}")
+                End If
+            End If
+
+            ' Cache MISS - neu laden
+            LOGGER.Debug($"Cache MISS: {cacheKey} - Loading from DB...")
+            Dim result = loadFunction()
+
+            If result IsNot Nothing Then
+                _cache(cacheKey) = New CachedItem With {
+                    .Data = result.Copy(),
+                    .Timestamp = DateTime.Now,
+                    .Timeout = If(timeout, _defaultTimeout)
+                }
+            End If
+
+            Return result
+        End SyncLock
+    End Function
+
+    ''' <summary>
+    ''' Bestimmten Cache-Eintrag invalidieren
+    ''' </summary>
+    Public Shared Sub Invalidate(cacheKey As String)
+        SyncLock _lockObject
+            If _cache.ContainsKey(cacheKey) Then
+                _cache.Remove(cacheKey)
+                LOGGER.Debug($"Cache INVALIDATED: {cacheKey}")
+            End If
+        End SyncLock
+    End Sub
+
+    ''' <summary>
+    ''' Alle Cache-Einträge löschen
+    ''' </summary>
+    Public Shared Sub ClearAll()
+        SyncLock _lockObject
+            Dim count = _cache.Count
+            _cache.Clear()
+            LOGGER.Info($"Cache CLEARED: {count} entries removed")
+        End SyncLock
+    End Sub
+
+    ''' <summary>
+    ''' Abgelaufene Einträge entfernen
+    ''' </summary>
+    Public Shared Sub CleanupExpired()
+        SyncLock _lockObject
+            Dim expiredKeys = _cache.Where(Function(kvp) kvp.Value.IsExpired).
+                                     Select(Function(kvp) kvp.Key).ToList()
+
+            For Each key In expiredKeys
+                _cache.Remove(key)
+            Next
+
+            If expiredKeys.Count > 0 Then
+                LOGGER.Debug($"Cache CLEANUP: {expiredKeys.Count} expired entries removed")
+            End If
+        End SyncLock
+    End Sub
+
+    ''' <summary>
+    ''' Cache-Statistiken
+    ''' </summary>
+    Public Shared Function GetStatistics() As String
+        SyncLock _lockObject
+            Return $"Cache Entries: {_cache.Count}, Default Timeout: {_defaultTimeout.TotalMinutes:F1} min"
+        End SyncLock
+    End Function
+End Class