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Attribute VB_Name = "modPoolMngr" Option Explicit 'Note: this is a simple example of a pool manager. For demo purposes, 'if it does not find a list of servers to initialize, it creates an initial list with 'intrface project server as thge only member of the list. 'It should be quite straightforward to extend this implemntation to support 'a custom list of objects for your own environment needs. 'The allocation scheme could also be much more sophisticated to 'reflect the specific managment needs of your environment. Type ProjectInfoStruc Prev As Integer Next As Integer nFirstSvrNode As Integer strProgID As String intCurUseCount As Integer intMinUseCount As Integer intMaxUseCount As Integer intCloseDelay As Integer bLookAheadCreate As Integer End Type Type ServerInstanceStruc Prev As Integer Next As Integer ObjHandle As Object DeallocTime As Date bInUse As Integer End Type Global Const gnINFO_TYPE = 0 Global Const gnINST_TYPE = 1 Global gaPrjInfo() As ProjectInfoStruc Global gaSvrInst() As ServerInstanceStruc Global gnFirstPrjNode As Integer 'Linked List implementation conventions: 'a root node is always available at index mnXXXX_ROOT 'when node.prev = node that node is the 1st member of a list 'when node.next = gnNIL that node is the last member of a list Const mINFO_FREE_ROOT = 0 Const mINST_FREE_ROOT = 0 Global Const gnNIL = -1 Const mnMAX_NODES = 32000 Const mstrINI_POOL_MNGR_FILE_NAME = "poolmngr.ini" Const mstrINI_POOL_MNGR_KEY = "PoolManager" Const mstrINI_POOL_SVR_KEY = "PoolSvr" #If Win32 Then Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpDefault As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long Declare Function WritePrivateProfileString Lib "kernel32" Alias "WritePrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpString As Any, ByVal lplFileName As String) As Long #Else Declare Function GetPrivateProfileString Lib "Kernel" (ByVal Secname1$, ByVal Keynamei$, ByVal Def1$, ByVal Ret1$, ByVal Size1%, ByVal lpFileName$) As Integer Declare Function WritePrivateProfileString% Lib "Kernel" (ByVal lpAppName$, ByVal lpKeyName$, ByVal lpString$, ByVal lpFileName$) #End If Sub Main() frmPoolMngr.Show End Sub Sub InitProjectArray() Dim strPrjSettings As String Dim bDone As Integer Dim i As Integer Dim j As Integer Dim nPrjNode As Integer Dim nPrevPrjNode As Integer Dim nSvrNode As Integer Dim intPtr1 As Integer Dim intPtr2 As Integer 'Initialize Linked List Pools and set root references to themselves ReDim gaPrjInfo(0) As ProjectInfoStruc 'alloc mINFO_FREE_ROOT gaPrjInfo(mINFO_FREE_ROOT).Prev = mINFO_FREE_ROOT gaPrjInfo(mINFO_FREE_ROOT).Next = mINFO_FREE_ROOT ReDim gaSvrInst(0) As ServerInstanceStruc 'alloc mINST_FREE_ROOT gaSvrInst(mINST_FREE_ROOT).Prev = mINST_FREE_ROOT gaSvrInst(mINST_FREE_ROOT).Next = mINST_FREE_ROOT i = 0 While Not bDone strPrjSettings = IniStringGet(mstrINI_POOL_SVR_KEY & Format$(i)) If strPrjSettings = "" Then If i = 0 Then InitPoolSvrList Else bDone = True End If Else nPrjNode = NodeGet(gnINFO_TYPE) If nPrjNode = gnNIL Then bDone = True Else If i = 0 Then gnFirstPrjNode = nPrjNode nPrevPrjNode = nPrjNode Else gaPrjInfo(nPrevPrjNode).Next = nPrjNode End If gaPrjInfo(nPrjNode).Prev = nPrevPrjNode gaPrjInfo(nPrjNode).Next = gnNIL gaPrjInfo(nPrjNode).nFirstSvrNode = gnNIL gaPrjInfo(nPrjNode).intCurUseCount = 0 'Parse Ini string and initialize Project Info struc intPtr1 = 1 intPtr2 = InStr(intPtr1, strPrjSettings, ",") If intPtr2 > 0 Then gaPrjInfo(nPrjNode).strProgID = Mid$(strPrjSettings, intPtr1, intPtr2 - intPtr1) intPtr1 = intPtr2 + 1 intPtr2 = InStr(intPtr1, strPrjSettings, ",") If intPtr2 > 0 Then gaPrjInfo(nPrjNode).intMinUseCount = Val(Mid$(strPrjSettings, intPtr1, intPtr2 - intPtr1)) intPtr1 = intPtr2 + 1 intPtr2 = InStr(intPtr1, strPrjSettings, ",") If intPtr2 > 0 Then gaPrjInfo(nPrjNode).intMaxUseCount = Val(Mid$(strPrjSettings, intPtr1, intPtr2 - intPtr1)) intPtr1 = intPtr2 + 1 intPtr2 = InStr(intPtr1, strPrjSettings, ",") If intPtr2 > 0 Then gaPrjInfo(nPrjNode).intCloseDelay = Val(Mid$(strPrjSettings, intPtr1, intPtr2 - intPtr1)) gaPrjInfo(nPrjNode).bLookAheadCreate = Val(Mid$(strPrjSettings, intPtr2 + 1)) 'Initialize Server pool to minimum size For j = 0 To gaPrjInfo(nPrjNode).intMinUseCount - 1 nSvrNode = GetNewServerNode(nPrjNode) If nSvrNode = gnNIL Then Exit For Set gaSvrInst(nSvrNode).ObjHandle = CreateObject(gaPrjInfo(nPrjNode).strProgID) gaSvrInst(nSvrNode).bInUse = False Next j i = i + 1 nPrevPrjNode = nPrjNode End If End If Wend End Sub Sub InitPoolSvrList() 'Define an initial Pool Server List entry so that the pool manager can be demoed Const strINTERFACE_PROG_ID = "InterfaceProj.ServerInterface" Const strPASSTHRU_PROG_ID = "PassThruProj.PassThruClass" Dim strTmp As String strTmp = strINTERFACE_PROG_ID & "," & "1,6,60,-1" IniStringSet mstrINI_POOL_SVR_KEY & "0", strTmp strTmp = strPASSTHRU_PROG_ID & "," & "1,6,60,-1" 'ProgId, MinPoolSize, MaxPoolSize, CloseDelay, LookAheadCreate IniStringSet mstrINI_POOL_SVR_KEY & "1", strTmp End Sub Sub NodeAppend(rnNodeType As Integer, rnBaseNode As Integer, rnNewNode As Integer) 'Append rnNewNode next of rnBaseNode If rnNodeType = gnINFO_TYPE Then gaPrjInfo(rnNewNode).Next = gaPrjInfo(rnBaseNode).Next gaPrjInfo(rnNewNode).Prev = rnBaseNode If gaPrjInfo(rnBaseNode).Next <> gnNIL Then gaPrjInfo(gaPrjInfo(rnBaseNode).Next).Prev = rnNewNode End If gaPrjInfo(rnBaseNode).Next = rnNewNode ElseIf rnNodeType = gnINST_TYPE Then gaSvrInst(rnNewNode).Next = gaSvrInst(rnBaseNode).Next gaSvrInst(rnNewNode).Prev = rnBaseNode If gaSvrInst(rnBaseNode).Next <> gnNIL Then gaSvrInst(gaSvrInst(rnBaseNode).Next).Prev = rnNewNode End If gaSvrInst(rnBaseNode).Next = rnNewNode End If End Sub Function NodeGet(rnNodeType As Integer) As Integer 'Return a new Node immediately next of ROOT NodeGet = gnNIL If rnNodeType = gnINFO_TYPE Then If gaPrjInfo(mINFO_FREE_ROOT).Next = mINFO_FREE_ROOT Then If Not NodeGrowLinkedList(gnINFO_TYPE, 2) Then Exit Function End If NodeGet = gaPrjInfo(mINFO_FREE_ROOT).Next gaPrjInfo(mINFO_FREE_ROOT).Next = gaPrjInfo(gaPrjInfo(mINFO_FREE_ROOT).Next).Next gaPrjInfo(gaPrjInfo(mINFO_FREE_ROOT).Next).Prev = mINFO_FREE_ROOT ElseIf rnNodeType = gnINST_TYPE Then If gaSvrInst(mINST_FREE_ROOT).Next = mINST_FREE_ROOT Then If Not NodeGrowLinkedList(gnINST_TYPE, 8) Then Exit Function End If NodeGet = gaSvrInst(mINST_FREE_ROOT).Next gaSvrInst(mINST_FREE_ROOT).Next = gaSvrInst(gaSvrInst(mINST_FREE_ROOT).Next).Next gaSvrInst(gaSvrInst(mINST_FREE_ROOT).Next).Prev = mINST_FREE_ROOT End If End Function Sub CloseOpenServers() Dim nPrjNode As Integer Dim nSvrNode As Integer On Error GoTo cosErr nPrjNode = gnFirstPrjNode While nPrjNode <> gnNIL nSvrNode = gaPrjInfo(nPrjNode).nFirstSvrNode While nSvrNode <> gnNIL Set gaSvrInst(nSvrNode).ObjHandle = Nothing nSvrNode = gaSvrInst(nSvrNode).Next Wend nPrjNode = gaPrjInfo(nPrjNode).Next Wend GoTo cosExit cosErr: DisplayError Resume cosExit cosExit: End Sub Sub DisplayError() #If gbDEBUG2 Then MsgBox Error$ #End If End Sub Function GetNewServerNode(rnProjNode As Integer) As Integer 'Get a new Server node and initialize its references Dim nSvrNode As Integer On Error GoTo gnsnErr nSvrNode = NodeGet(gnINST_TYPE) GetNewServerNode = nSvrNode If nSvrNode = gnNIL Then Exit Function 'Should log error gaSvrInst(nSvrNode).Prev = nSvrNode gaSvrInst(nSvrNode).Next = gaPrjInfo(rnProjNode).nFirstSvrNode If gaPrjInfo(rnProjNode).nFirstSvrNode <> gnNIL Then gaSvrInst(gaPrjInfo(rnProjNode).nFirstSvrNode).Prev = nSvrNode End If gaPrjInfo(rnProjNode).nFirstSvrNode = nSvrNode GoTo gnsnExit gnsnErr: DisplayError Resume gnsnExit gnsnExit: End Function Function NodeGrowLinkedList(rnNodeType As Integer, rnIncrease As Integer) As Integer Dim i As Integer Dim nLast As Integer Dim nFirst As Integer On Error GoTo gllErr NodeGrowLinkedList = False If rnIncrease < 1 Then Exit Function If rnNodeType = gnINFO_TYPE Then nLast = UBound(gaPrjInfo) If nLast + rnIncrease < mnMAX_NODES Then ReDim Preserve gaPrjInfo(nLast + rnIncrease) nFirst = nLast + 1 gaPrjInfo(gaPrjInfo(mINFO_FREE_ROOT).Next).Prev = nLast + rnIncrease gaPrjInfo(nLast + rnIncrease).Next = gaPrjInfo(mINFO_FREE_ROOT).Next gaPrjInfo(mINFO_FREE_ROOT).Next = nFirst gaPrjInfo(nFirst).Prev = mINFO_FREE_ROOT gaPrjInfo(nFirst).Next = nFirst + 1 For i = nFirst + 1 To nLast + rnIncrease - 1 gaPrjInfo(i).Prev = i - 1 gaPrjInfo(i).Next = i + 1 Next i gaPrjInfo(i).Prev = i - 1 Else nLast = UBound(gaSvrInst) If nLast + rnIncrease < mnMAX_NODES Then ReDim Preserve gaSvrInst(nLast + rnIncrease) nFirst = nLast + 1 gaSvrInst(gaSvrInst(mINST_FREE_ROOT).Next).Prev = nLast + rnIncrease gaSvrInst(nLast + rnIncrease).Next = gaSvrInst(mINST_FREE_ROOT).Next gaSvrInst(mINST_FREE_ROOT).Next = nFirst gaSvrInst(nFirst).Prev = mINST_FREE_ROOT gaSvrInst(nFirst).Next = nFirst + 1 For i = nFirst + 1 To nLast + rnIncrease - 1 gaSvrInst(i).Prev = i - 1 gaSvrInst(i).Next = i + 1 Next i gaSvrInst(i).Prev = i - 1 End If NodeGrowLinkedList = True GoTo gllExit gllErr: DisplayError Resume gllExit gllExit: End Function Sub NodeRemove(rnNodeType As Integer, nRemoveNode As Integer) 'Extract node from siblings. If rnNodeType = gnINFO_TYPE Then gaPrjInfo(gaPrjInfo(nRemoveNode).Prev).Next = gaPrjInfo(nRemoveNode).Next If gaPrjInfo(nRemoveNode).Next <> gnNIL Then gaPrjInfo(gaPrjInfo(nRemoveNode).Next).Prev = gaPrjInfo(nRemoveNode).Prev End If ElseIf rnNodeType = gnINST_TYPE Then gaSvrInst(gaSvrInst(nRemoveNode).Prev).Next = gaSvrInst(nRemoveNode).Next If gaSvrInst(nRemoveNode).Next <> gnNIL Then gaSvrInst(gaSvrInst(nRemoveNode).Next).Prev = gaSvrInst(nRemoveNode).Prev End If Else Exit Sub End If NodeReturn rnNodeType, nRemoveNode End Sub Sub NodeReturn(rnNodeType As Integer, nReturnNode As Integer) 'Insert nReturnNode immediately next ROOT If rnNodeType = gnINFO_TYPE Then gaPrjInfo(nReturnNode).Next = gaPrjInfo(mINFO_FREE_ROOT).Next gaPrjInfo(gaPrjInfo(mINFO_FREE_ROOT).Next).Prev = nReturnNode gaPrjInfo(mINFO_FREE_ROOT).Next = nReturnNode gaPrjInfo(nReturnNode).Prev = mINFO_FREE_ROOT ElseIf rnNodeType = gnINST_TYPE Then gaSvrInst(nReturnNode).Next = gaSvrInst(mINST_FREE_ROOT).Next gaSvrInst(gaSvrInst(mINST_FREE_ROOT).Next).Prev = nReturnNode gaSvrInst(mINST_FREE_ROOT).Next = nReturnNode gaSvrInst(nReturnNode).Prev = mINST_FREE_ROOT End If End Sub Function IniStringGet(KeyString As String) As String Dim strIniBuffer As String * 255 On Error GoTo gisErr #If Win32 Then Dim lRetLen As Long lRetLen = GetPrivateProfileString(mstrINI_POOL_MNGR_KEY, KeyString, "", strIniBuffer, 255, mstrINI_POOL_MNGR_FILE_NAME) If lRetLen > 0 Then IniStringGet = Left$(strIniBuffer, lRetLen) #Else Dim nRetLen As Integer nRetLen = GetPrivateProfileString(mstrINI_POOL_MNGR_KEY, KeyString, "", strIniBuffer, 255, mstrINI_POOL_MNGR_FILE_NAME) If nRetLen > 0 Then IniStringGet = Left$(strIniBuffer, nRetLen) #End If GoTo gisExit gisErr: DisplayError Resume gisExit gisExit: End Function Sub IniStringSet(KeyString As String, ValString As String) Dim sIniGroupKey As String On Error GoTo sisErr #If Win32 Then Dim lTmp As Long lTmp = WritePrivateProfileString(mstrINI_POOL_MNGR_KEY, KeyString, ValString, mstrINI_POOL_MNGR_FILE_NAME) #Else Dim ntmp As Integer ntmp = WritePrivateProfileString(mstrINI_POOL_MNGR_KEY, KeyString, ValString, mstrINI_POOL_MNGR_FILE_NAME) #End If GoTo sisExit sisErr: DisplayError Resume sisExit sisExit: End Sub 
