/// <summary>
/// Traverse a SelectExpandClause using given functions.
/// </summary>
/// <typeparam name="T">Type of the sub processing result for expand items.</typeparam>
/// <param name="selectExpandClause">The select expand clause for evaluation.</param>
/// <param name="processSubResult">The method to deal with sub expand result.</param>
/// <param name="combineSelectAndExpand">The method to combine select and expand result lists.</param>
/// <param name="processApply">The method to deal with apply result.</param>
/// <param name="result">The result of the traversing.</param>
internal static void Traverse <T>(this SelectExpandClause selectExpandClause, Func <string, T, T> processSubResult, Func <IList <string>, IList <T>, T> combineSelectAndExpand, Func <ApplyClause, T> processApply, out T result)
{
List <string> selectList = selectExpandClause.GetCurrentLevelSelectList();
List <T> expandList = new List <T>();
foreach (SelectItem selectItem in selectExpandClause.SelectedItems)
{
// $expand=..../$ref
ExpandedNavigationSelectItem expandSelectItem = selectItem as ExpandedNavigationSelectItem;
if (expandSelectItem != null)
{
string currentExpandClause = String.Join("/", expandSelectItem.PathToNavigationProperty.WalkWith(PathSegmentToStringTranslator.Instance).ToArray());
T subResult = default(T);
if (expandSelectItem.SelectAndExpand.SelectedItems.Any())
{
Traverse(expandSelectItem.SelectAndExpand, processSubResult, combineSelectAndExpand, processApply, out subResult);
}
if (expandSelectItem.ApplyOption != null && processApply != null)
{
subResult = processApply(expandSelectItem.ApplyOption);
}
var expandItem = processSubResult(currentExpandClause, subResult);
if (expandItem != null)
{
expandList.Add(expandItem);
}
}
else
{
ExpandedReferenceSelectItem expandRefItem = selectItem as ExpandedReferenceSelectItem;
if (expandRefItem != null)
{
string currentExpandClause = String.Join("/", expandRefItem.PathToNavigationProperty.WalkWith(PathSegmentToStringTranslator.Instance).ToArray());
currentExpandClause += "/$ref";
var expandItem = processSubResult(currentExpandClause, default(T));
if (expandItem != null)
{
expandList.Add(expandItem);
}
}
}
}
result = combineSelectAndExpand(selectList, expandList);
}
/// <summary>
/// Handle an ExpandedReferenceSelectItem
/// </summary>
/// <param name="item">the item to Handle</param>
public virtual void Handle(ExpandedReferenceSelectItem item)
{
throw new NotImplementedException();
}
/// <summary>
/// Translate an ExpandedReferenceSelectItem
/// </summary>
/// <param name="item">the item to Translate</param>
/// <returns>Defined by the implementer</returns>
public virtual T Translate(ExpandedReferenceSelectItem item)
{
throw new NotImplementedException();
}