internal static TResult Aggregate <T, TResult>(AggregateNames aggregateName, Expression <Func <T, TResult> > projection, Expression <Func <T, bool> > predicate = null, string connectionName = null, DbConnection connection = null, IConfiguration config = null)
where T : class
where TResult : struct
{
string providerName = null;
if (connection == null)
{
providerName = DbFactory.GetProviderInvariantName(connectionName, typeof(T), config);
connection = DbFactory.CreateConnection(connectionName, typeof(T), config);
}
var sql = SqlBuilder.GetSelectAggregationStatement(aggregateName.ToString(), projection, predicate, DialectFactory.GetProvider(connection, providerName));
return(RetrieveScalar <TResult>(sql, connection: connection, config: config));
}
public static AggregateName GetAggregateName(this Type aggregateType)
{
return(AggregateNames.GetOrAdd(
aggregateType,
t =>
{
if (!typeof(IAggregateRoot).GetTypeInfo().IsAssignableFrom(aggregateType) &&
!typeof(IIdentity).GetTypeInfo().IsAssignableFrom(aggregateType))
{
throw new ArgumentException($"Type '{aggregateType.PrettyPrint()}' is not an aggregate root or identity");
}
return new AggregateName(
t.GetTypeInfo().GetCustomAttributes <AggregateNameAttribute>().SingleOrDefault()?.Name ??
t.Name);
}));
}
