/// <summary>
/// Parses the supplied expression into a hierarchical list-based representation for easier consumption.
/// </summary>
/// <param name="fieldsExpression">The fields expression to be parsed.</param>
/// <returns>A hierarchical list-based representation of the fields expression.</returns>
public IReadOnlyList <SelectedResourceMember> ParseFields(string fieldsExpression)
{
if (string.IsNullOrEmpty(fieldsExpression))
{
throw new ArgumentException("Field selection expression was not supplied.");
}
fieldsExpression = fieldsExpression.Trim();
int anchor = 0;
int pos = 0;
var state = ParseState.SeekingMember;
var allMembers = new List <SelectedResourceMember>();
var stack = new Stack <List <SelectedResourceMember> >();
var members = allMembers;
while (pos < fieldsExpression.Length || state == ParseState.ChildrenParsed)
{
switch (state)
{
case ParseState.AllMembersIncluded:
if (fieldsExpression[pos] != ')')
{
throw new ArgumentException("Fields expression uses '*' without enclosing parenthesis.");
}
state = ParseState.ChildrenParsed;
break;
case ParseState.SeekingMember:
// Skip over leading spaces
if (fieldsExpression[pos] == ' ')
{
anchor = ++pos;
}
// Check for the "all" symbol
else if (fieldsExpression[pos] == '*')
{
state = ParseState.AllMembersIncluded;
pos++;
}
// Check for premature child fields closing symbol with no children listed
else if (fieldsExpression[pos] == ')' && !members.Any())
{
throw new ArgumentException(
"Fields sub-expression does not contain any field names.");
}
else
{
state = ParseState.ParsingMember;
}
break;
case ParseState.ParsingMember:
if (fieldsExpression[pos] == ',')
{
state = ParseState.MemberParsed;
}
else if (fieldsExpression[pos] == '(')
{
state = ParseState.ParsingChildren;
}
else if (fieldsExpression[pos] == ')')
{
state = ParseState.ChildrenParsed;
}
else if (fieldsExpression[pos] == ' ')
{
state = ParseState.MemberParsed;
}
else if (!(char.IsLetterOrDigit(fieldsExpression[pos]) || fieldsExpression[pos] == '_'))
{
throw new ArgumentException(
string.Format("Unexpected character '{0}' in member name in field selection expression.", fieldsExpression[pos]));
}
else
{
pos++;
}
break;
case ParseState.MemberParsed:
string parsedMemberName = fieldsExpression.Substring(anchor, pos - anchor);
if (!string.IsNullOrEmpty(parsedMemberName))
{
members.Add(new SelectedResourceMember(parsedMemberName));
}
state = ParseState.SeekingMember;
anchor = ++pos;
break;
case ParseState.ParsingChildren:
var currentMember = new SelectedResourceMember(fieldsExpression.Substring(anchor, pos - anchor));
members.Add(currentMember);
state = ParseState.SeekingMember;
anchor = ++pos;
stack.Push(members);
members = currentMember.Children;
break;
case ParseState.ChildrenParsed:
string memberName = fieldsExpression.Substring(anchor, pos - anchor);
if (!string.IsNullOrEmpty(memberName) && memberName != ")")
{
members.Add(new SelectedResourceMember(memberName));
}
anchor = ++pos;
if (!stack.Any())
{
throw new ArgumentException("Fields expression contains too many closing parenthesis.");
}
members = stack.Pop();
state = ParseState.SeekingMember;
break;
}
}
string finalMemberName = fieldsExpression.Substring(anchor, pos - anchor);
if (!string.IsNullOrEmpty(finalMemberName))
{
members.Add(new SelectedResourceMember(finalMemberName));
}
if (stack.Count != 0)
{
throw new ArgumentException("Fields expression contains unclosed parenthesis.");
}
return(allMembers);
}
public IList <IDictionary> ProcessResults(
CompositeQuery query,
Hashtable parentRow,
string[] parentKeys,
IReadOnlyList <SelectedResourceMember> fieldSelections,
NullValueHandling nullValueHandling,
IDictionary <string, string> recursiveChildKeyMap = null)
{
var results = new List <IDictionary>();
var currentEnumerator = query.GetEnumerator(parentRow, parentKeys, recursiveChildKeyMap);
do
{
// Nothing to enumerate?
if (currentEnumerator == null || currentEnumerator.IsComplete)
{
return(results);
}
// Get current row
var currentRow = (Hashtable)currentEnumerator.Current;
if (currentRow == null)
{
break;
}
// If the child is outside the context of the parent, quit processing
if (parentRow != null && !IsChildRow(parentKeys, parentRow, recursiveChildKeyMap, currentRow))
{
break;
}
// Convert the row to serializable form
var resultItem = GetItem(currentRow, query.DataFields, query.OrderedFieldNames, fieldSelections, nullValueHandling);
// Process the children
foreach (var childQuery in query.ChildQueries)
{
SelectedResourceMember selectedMember = null;
string childCollectionName = childQuery.DisplayName;
// Check to see if this collection should be included
if (fieldSelections != null && fieldSelections.Count > 0)
{
selectedMember = fieldSelections.FirstOrDefault(x => x.Equals(childCollectionName) || x.Equals("*"));
if (selectedMember == null)
{
continue;
}
}
resultItem[childCollectionName] =
ProcessResults(
childQuery,
currentRow,
query.KeyFields,
selectedMember == null
? null
: selectedMember.Children,
nullValueHandling)
.ApplyCardinality(childQuery.IsSingleItemResult);
}
// Is the current query recursive?
if (query.IsRecursive)
{
// Need to add a child "self" collection with recursion
resultItem[query.DisplayName] = ProcessResults(
query,
currentRow,
query.KeyFields,
fieldSelections,
nullValueHandling,
query.RecursiveChildKeyMap);
// Strip out hierarchical support fields from the response
resultItem.Keys.OfType <string>()
.Where(k => k.StartsWith(CompositeDefinitionHelper.HierarchyMarker))
.ToList()
.ForEach(k => resultItem.Remove(k));
// Add the row - we're done.
results.Add(resultItem);
}
else
{
// Just add the row - we're done.
results.Add(resultItem);
}
}while (currentEnumerator.MoveNext());
return(results);
}
