SqlStoredProc池

ゝ一世哀愁。 2022-03-29 07:16 32阅读 0赞

unit SqlStoredPool;  
interface  
uses  
Classes, Windows, SysUtils, forms, DB, SqlExpr, FMTBcd;  
type  
TSQLStoredPool = class(TObject)  
private  
FObjList:TThreadList;  
FTimeout: Integer;  
FMaxCount: Integer;  
FSemaphore: Cardinal;  
function CreateNewInstance(List:TList): TSQLStored;  
function GetLock(List:TList;Index: Integer): Boolean;  
public  
property Timeout:Integer read FTimeout write FTimeout;  
property MaxCount:Integer read FMaxCount;  
constructor Create(ACapicity:Integer=30);overload;  
destructor Destroy;override;  
function Lock: TSQLStored;  
procedure UnLock(var Value: TSQLStored);  
end;  
var  
DBXStoredPool: TSQLStoredPool;  
implementation  
constructor TSQLStoredPool.Create(ACapicity:Integer=30);  
begin  
FObjList:=TThreadList.Create;  
FTimeout := 3000;  
FMaxCount := ACapicity;  
FSemaphore := CreateSemaphore(nil, FMaxCount, FMaxCount, nil);  
end;  
function TSQLStoredPool.CreateNewInstance(List:TList): TSQLStored;  
var  
p: TSQLStored;  
begin  
try  
p := TSQLStored.Create(nil);  
p.Tag := 1;  
List.Add(p);  
Result := p;  
except  
Result := nil;  
Exit;  
end;  
end;  
destructor TSQLStoredPool.Destroy;  
var  
i: Integer;  
List:TList;  
begin  
List:=FObjList.LockList;  
try  
for i := List.Count - 1 downto 0 do  
begin  
TSQLStored(List\[i\]).Free;  
end;  
finally  
FObjList.UnlockList;  
end;  
FObjList.Free;  
FObjList := nil;  
CloseHandle(FSemaphore);  
inherited Destroy;  
end;  
function TSQLStoredPool.GetLock(List:TList;Index: Integer): Boolean;  
begin  
try  
Result := TSQLStored(List\[Index\]).Tag = 0;  
if Result then  
TSQLStored(List\[Index\]).Tag := 1;  
except  
Result :=False;  
Exit;  
end;  
end;  
function TSQLStoredPool.Lock: TSQLStored;  
var  
i: Integer;  
List:TList;  
begin  
try  
Result := nil;  
if WaitForSingleObject(FSemaphore, Timeout) = WAIT\_FAILED then Exit;  
List:=FObjList.LockList;  
try  
for i := 0 to List.Count - 1 do  
begin  
if GetLock(List,i) then  
begin  
Result := TSQLStored(List\[i\]);  
// PostMessage(Application.MainForm.Handle, 8888,23,0);  
Exit;  
end;  
end;  
if List.Count < MaxCount then  
begin  
Result := CreateNewInstance(List);  
// PostMessage(Application.MainForm.Handle, 8888,21,0);  
end;  
finally  
FObjList.UnlockList;  
end;  
except  
Result :=nil;  
Exit;  
end;  
end;  
procedure TSQLStoredPool.Unlock(var Value: TSQLStored);  
var  
List:TList;  
begin  
try  
List:=FObjList.LockList;  
try  
TSQLStored(List\[List.IndexOf(Value)\]).Tag :=0;  
ReleaseSemaphore(FSemaphore, 1, nil);  
finally  
FObjList.UnlockList;  
end;  
// PostMessage(Application.MainForm.Handle, 8888, 22, 0);  
except  
Exit;  
end;  
end;  
initialization  
DBXStoredPool := TSQLStoredPool.Create();  
finalization  
FreeAndNil(DBXStoredPool);  
end.