// Update the local cache with current regulations from the database for a specific customer
public void UpdateMemAndXmlCacheForCustomerFromDB(int customerID, bool forceUpdateIfCacheNotExpiredYet)
{
// Get the current cache expiration for this customer
DateTime _cacheExpireTime = GetCacheExpirationForCustomer(customerID);
// Only update the cache if it is expired, or we have been explicitly told to do so
if ((DateTime.UtcNow >= _cacheExpireTime) || (forceUpdateIfCacheNotExpiredYet))
{
// Protect this section with our ReadWriterLockAlt that handles concurrency issues for us
using (_cacheReadWriteLocker.WriteLock())
{
// If multiple threads were calling this same routine, we might've had to wait around awhile, so we
// will check the cache expiration again (unless we are in the "force update" mode)
_cacheExpireTime = GetCacheExpirationForCustomer(customerID);
if ((!forceUpdateIfCacheNotExpiredYet) && (DateTime.UtcNow >= _cacheExpireTime))
{
// Gather the regulations for current customer from the database
List <RegulatedHours_ExperimentalDBSchemaV1DTO> customerRegsFromDB = GetRegulatedHoursForCustomerFromDB(customerID);
// Create cache object if doesn't exist yet
if (_cachedRegulations == null)
{
_cachedRegulations = new List <RegulatedHours_ExperimentalDBSchemaV1DTO>();
}
// Remove existing items from memory cache for the current customer
RegulatedHours_ExperimentalDBSchemaV1DTOPredicate predicate = new RegulatedHours_ExperimentalDBSchemaV1DTOPredicate(customerID, null, null);
List <RegulatedHours_ExperimentalDBSchemaV1DTO> cachedCustomerRegulations = _cachedRegulations.FindAll(predicate.CompareCustomerID);
foreach (RegulatedHours_ExperimentalDBSchemaV1DTO nextReg in cachedCustomerRegulations)
{
_cachedRegulations.Remove(nextReg);
}
// Add the customer regulations that were obtained from the physical database
_cachedRegulations.AddRange(customerRegsFromDB);
// Now rewrite the XML cache
RewriteXmlCache_WriteLockAlreadyAcquired();
// Finally, we will update the cache expiration for this customer so the cache won't try to be
// updated again for this customer until another hour from now. Note that we need to be thread-safe
// in upating the expiration time, because another thread might be trying to read it
lock (_cacheExpirationsByCustomerId)
{
_cacheExpirationsByCustomerId[customerID] = DateTime.UtcNow.AddHours(1);
}
}
else
{
System.Diagnostics.Debug.WriteLine("Cache not expired yet, no need to update");
}
}
}
else
{
/*System.Diagnostics.Debug.WriteLine("Cache not expired yet, no need to update");*/
}
}
// Return a list of all regulations for a given customer, meter, bay, or combination of such parameters (from cache)
public List <RegulatedHours_ExperimentalDBSchemaV1DTO> GetRegulationsWithSameScope(int?cid, int?bayNumber, int?mid)
{
// Update the cache in background thread. The update routine will return immediately if the cache isn't expired yet
if (cid.HasValue)
{
// Run this async so that the main thread can continue
var task = new Task(() => { UpdateMemAndXmlCacheForCustomerFromDB(cid.Value, false); });
task.Start();
}
RegulatedHours_ExperimentalDBSchemaV1DTOPredicate predicate = new RegulatedHours_ExperimentalDBSchemaV1DTOPredicate(cid, bayNumber, mid);
List <RegulatedHours_ExperimentalDBSchemaV1DTO> result = null;
// Protect this section with our ReadWriterLockAlt that handles concurrency issues for us
using (_cacheReadWriteLocker.ReadLock())
{
result = _cachedRegulations.FindAll(predicate.CompareVariableScope);
}
return(result);
}