/// <summary>
/// Event Handler that gets called before the Common Language Runtime (CLR) begins searching for Event
/// Handlers. This special Event gets hooked up for all AppDomains of the server (incl. the Default
/// Application Domain of the server exe).
/// <para>
/// In case an Exception was caused by an unavailable DB Connection the <see cref="DBConnectionBrokenCallback"/>
/// Event gets raised, which gets subscribed to in the TServerManager.StartServer Method and in the
/// Constructor of the 'TRemoteLoader' Class in order to kick off the attempts of restoring the broken
/// DB Connection.
/// </para>
/// </summary>
/// <param name="ASource">Provided automatically by .NET.</param>
/// <param name="AEventArgs">Provided automatically by .NET. (The Exception Property of this Argument
/// holds the Exception that just occurred.)</param>
public static void FirstChanceHandler(object ASource, FirstChanceExceptionEventArgs AEventArgs)
{
if (TExceptionHelper.IsExceptionCausedByUnavailableDBConnectionServerSide(AEventArgs.Exception))
{
if (DBConnectionBrokenCallback != null)
{
DBConnectionBrokenCallback(ASource, AEventArgs.Exception);
}
}
else if (AEventArgs.Exception is OutOfMemoryException)
{
TLogging.Log(String.Format("FirstChanceException event raised because of an *out of memory condition* in {0}: {1}",
AppDomain.CurrentDomain.FriendlyName, AEventArgs.Exception.Message));
TLogging.LogStackTrace(TLoggingType.ToLogfile);
}
else
{
if (TLogging.DebugLevel >= 5)
{
TLogging.Log(String.Format("FirstChanceException event raised in {0}: {1}",
AppDomain.CurrentDomain.FriendlyName, AEventArgs.Exception.Message));
TLogging.LogStackTrace(TLoggingType.ToLogfile);
}
}
}
/// <summary>
/// Establishes a new Database connection to the Database
/// for TTimedProcessing.
/// </summary>
/// <remarks>
/// We don't want to use the global Ict.Common.DB.DBAccess.GDBAccessObj object in the Default
/// AppDomain because this is reserved for OpenPetraServer's internal use (eg. verifying Client
/// connection reqests)!
/// </remarks>
/// <returns>the database connection object</returns>
private static TDataBase EstablishDBConnection()
{
TDataBase FDBAccessObj;
bool ExceptionCausedByUnavailableDBConn;
try
{
FDBAccessObj = DBAccess.SimpleEstablishDBConnection("Servers's DB Connection for TimedProcessing");
}
catch (Exception Exc)
{
ExceptionCausedByUnavailableDBConn = TExceptionHelper.IsExceptionCausedByUnavailableDBConnectionServerSide(Exc);
if (!ExceptionCausedByUnavailableDBConn)
{
TLogging.Log("Timed Processing: Exception occured while establishing connection to Database Server: " + Exc.ToString());
throw;
}
else
{
FDBAccessObj = null; // This gets handled in the calling Method!
}
}
return(FDBAccessObj);
}