private IAggregatorFactory BuildAggregatorFactory(ReteBuilderContext context, AggregateElement element)
{
IAggregatorFactory factory;
switch (element.Name)
{
case AggregateElement.CollectName:
factory = new CollectionAggregatorFactory();
break;
case AggregateElement.GroupByName:
factory = new GroupByAggregatorFactory();
break;
case AggregateElement.ProjectName:
factory = new ProjectionAggregatorFactory();
break;
case AggregateElement.FlattenName:
factory = new FlatteningAggregatorFactory();
break;
default:
throw new ArgumentException(
$"Unrecognized aggregate element. Name={element.Name}");
}
var compiledExpressions = CompileExpressions(context, element);
factory.Compile(element, compiledExpressions);
return(factory);
}
private IAggregatorFactory BuildAggregatorFactory(ReteBuilderContext context, AggregateElement element)
{
IAggregatorFactory factory;
switch (element.Name)
{
case AggregateElement.CollectName:
factory = new CollectionAggregatorFactory();
break;
case AggregateElement.GroupByName:
factory = new GroupByAggregatorFactory();
break;
case AggregateElement.ProjectName:
factory = new ProjectionAggregatorFactory();
break;
case AggregateElement.FlattenName:
factory = new FlatteningAggregatorFactory();
break;
default:
factory = GetCustomFactory(element);
break;
}
var compiledExpressions = CompileExpressions(context, element);
factory.Compile(element, compiledExpressions);
return(factory);
}
/// <summary>
/// Configure group by aggregator.
/// </summary>
/// <param name="keySelector">Key selection expressions.</param>
/// <param name="elementSelector">Element selection expression.</param>
/// <typeparam name="TSource">Type of source elements to aggregate.</typeparam>
/// <typeparam name="TKey">Type of grouping key.</typeparam>
/// <typeparam name="TElement">Type of grouping element.</typeparam>
public void GroupBy <TSource, TKey, TElement>(Expression <Func <TSource, TKey> > keySelector, Expression <Func <TSource, TElement> > elementSelector)
{
var aggregateFactory = new GroupByAggregatorFactory <TSource, TKey, TElement>(keySelector.Compile(), elementSelector.Compile());
_expressions["KeySelector"] = keySelector;
_expressions["ElementSelector"] = keySelector;
AggregatorFactory(GroupByName, aggregateFactory);
}