/// <summary>
/// Creates a new local system cache from one that was received remotely.
/// </summary>
/// <param name="dataSource"><see cref="DataSet"/> based data source used to interpret local measurement keys.</param>
/// <param name="remoteCache">Deserialized remote signal index cache.</param>
public SignalIndexCache(DataSet dataSource, SignalIndexCache remoteCache)
{
m_subscriberID = remoteCache.SubscriberID;
// If active measurements are defined, interpret signal cache in context of current measurement key definitions
if (dataSource != null && dataSource.Tables.Contains("ActiveMeasurements"))
{
DataTable activeMeasurements = dataSource.Tables["ActiveMeasurements"];
m_reference = new ConcurrentDictionary <int, MeasurementKey>();
foreach (KeyValuePair <int, MeasurementKey> signalIndex in remoteCache.Reference)
{
Guid signalID = signalIndex.Value.SignalID;
DataRow[] filteredRows = activeMeasurements.Select("SignalID = '" + signalID.ToString() + "'");
if (filteredRows.Length > 0)
{
DataRow row = filteredRows[0];
MeasurementKey key = MeasurementKey.LookUpOrCreate(signalID, row["ID"].ToNonNullString(MeasurementKey.Undefined.ToString()));
m_reference.TryAdd(signalIndex.Key, key);
}
}
m_unauthorizedSignalIDs = remoteCache.UnauthorizedSignalIDs;
}
else
{
// Just use remote signal index cache as-is if no local configuration exists
m_reference = remoteCache.Reference;
m_unauthorizedSignalIDs = remoteCache.UnauthorizedSignalIDs;
}
}
// Input keys can use DataSource for filtering desired set of input or output measurements
// based on any table and fields in the data set by using a filter expression instead of
// a list of measurement ID's. The format is as follows:
// FILTER <TableName> WHERE <Expression> [ORDER BY <SortField>]
// Source tables are expected to have at least the following fields:
//
// ID NVARCHAR Measurement key formatted as: ArchiveSource:PointID
// SignalID GUID Unique identification for measurement
// PointTag NVARCHAR Point tag of measurement
// Adder FLOAT Adder to apply to value, if any (default to 0.0)
// Multiplier FLOAT Multiplier to apply to value, if any (default to 1.0)
//
// Could have used standard SQL syntax here but didn't want to give user the impression
// that this a standard SQL expression when it isn't - so chose the word FILTER to make
// consumer was aware that this was not SQL, but SQL "like". The WHERE clause expression
// uses standard SQL syntax (it is simply the DataTable.Select filter expression).
/// <summary>
/// Parses input measurement keys from connection string setting.
/// </summary>
/// <param name="dataSource">The <see cref="DataSet"/> used to define input measurement keys.</param>
/// <param name="value">Value of setting used to define input measurement keys, typically "inputMeasurementKeys".</param>
/// <param name="measurementTable">Measurement table name used to load additional meta-data; this is not used when specifying a FILTER expression.</param>
/// <returns>User selected input measurement keys.</returns>
public static MeasurementKey[] ParseInputMeasurementKeys(DataSet dataSource, string value, string measurementTable = "ActiveMeasurements")
{
List <MeasurementKey> keys = new List <MeasurementKey>();
MeasurementKey key;
bool dataSourceAvailable = (object)dataSource != null;
if (string.IsNullOrWhiteSpace(value))
{
return(keys.ToArray());
}
value = value.Trim();
if (dataSourceAvailable && ParseFilterExpression(value, out string tableName, out string expression, out string sortField, out int takeCount))
{
foreach (DataRow row in dataSource.Tables[tableName].Select(expression, sortField).Take(takeCount))
{
key = MeasurementKey.LookUpOrCreate(row["SignalID"].ToNonNullString(Guid.Empty.ToString()).ConvertToType <Guid>(), row["ID"].ToString());
if (key != MeasurementKey.Undefined)
{
keys.Add(key);
}
}
}