public static JoinedEnumerable <TElement> Wrap <TElement>(IEnumerable <TElement> source, bool isOuter)
{
JoinedEnumerable <TElement> joinedSource
= source as JoinedEnumerable <TElement> ??
new JoinedEnumerable <TElement>(source);
joinedSource.IsOuter = isOuter;
return(joinedSource);
}
public static IEnumerable <TResult> Join <TOuter, TInner, TKey, TResult>(this JoinedEnumerable <TOuter> outer, IEnumerable <TInner> inner, Func <TOuter, TKey> outerKeySelector, Func <TInner, TKey> innerKeySelector, Func <TOuter, TInner, TResult> resultSelector, IEqualityComparer <TKey> comparer = null)
{
if (outer == null)
{
throw new ArgumentNullException("outer");
}
if (inner == null)
{
throw new ArgumentNullException("inner");
}
if (outerKeySelector == null)
{
throw new ArgumentNullException("outerKeySelector");
}
if (innerKeySelector == null)
{
throw new ArgumentNullException("innerKeySelector");
}
if (resultSelector == null)
{
throw new ArgumentNullException("resultSelector");
}
bool leftOuter = outer.IsOuter;
bool rightOuter = (inner is JoinedEnumerable <TInner>) && ((JoinedEnumerable <TInner>)inner).IsOuter;
if (leftOuter && rightOuter)
{
return(FullOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer));
}
if (leftOuter)
{
return(LeftOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer));
}
if (rightOuter)
{
return(RightOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer));
}
return(Enumerable.Join(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer));
}