public Query(Type elementType, string query, ModelMetadataProvider provider)
{
if (elementType == null) throw new ArgumentNullException("elementType");
if (provider == null) throw new ArgumentNullException("provider");
_elementType = elementType;
_provider = provider;
if (string.IsNullOrWhiteSpace(query)) query = string.Empty;
_originalQuery = query;
var grammar = new QueryLanguageGrammar();
var language = new LanguageData(grammar);
var parser = new Parser(language);
var tree = parser.Parse(query);
if (tree.Status == ParseTreeStatus.Parsed)
{
AssertEmpty(tree.Root.ChildNodes[2]); //groupBy
AssertEmpty(tree.Root.ChildNodes[3]); //pivot
AssertEmpty(tree.Root.ChildNodes[9]); //options
_limit = ProcessIntNode(tree.Root.ChildNodes[5]);
_offset = ProcessIntNode(tree.Root.ChildNodes[6]);
//TODO: when handling pivot, need to rework this
var metadata = provider.GetMetadataForType((Func<object>)null, elementType);
var properties = metadata.Properties.ToList();
if (tree.Root.ChildNodes[0].ChildNodes.Count == 0
|| (tree.Root.ChildNodes[0].ChildNodes.Count == 2 && tree.Root.ChildNodes[0].ChildNodes[1].Token != null && tree.Root.ChildNodes[0].ChildNodes[1].Token.Value == "*")) //select *
{
//select of all columns of elementType, just a pass through of all the columns
_outputType = elementType;
_selectStar = true;
_columns = MetadataToColumns(properties.OrderBy(p => p.Order));
}
else
{
_selectStar = false;
//create custom output type unless select contains all columns just reordered...
var selectList = tree.Root.ChildNodes[0].ClauseList();
if (!selectList.Any(e => !string.Equals(e.Term.Name, "identifier", StringComparison.Ordinal)))
{
//all identifiers, so just pass through current type for simplicity, no projection, exclude columns on client side
_outputType = elementType;
var selectListJoin = selectList.Join(properties, i => i.ToPropertyName(), p => p.PropertyName, (i,p) => p).ToList();
if (selectListJoin.Count != selectList.Count) throw new QueryParseException("Some of the identifiers passed in the select clause do not exist.");
_columns = MetadataToColumns(selectListJoin);
}
else
{
throw new NotImplementedException();
}
//populate columns list
}
var labelList = tree.Root.ChildNodes[7].ClauseList();
var labelListJoin = from l in labelList
join c in _columns on l.ChildNodes[0].ToPropertyName() equals c.Name
select new { l, c };
foreach (var j in labelListJoin)
{
j.c.Label = (string)j.l.ChildNodes[1].Token.Value;
}
var formatList = tree.Root.ChildNodes[8].ClauseList();
var formatListJoin = from f in formatList
join c in _columns on f.ChildNodes[0].ToPropertyName() equals c.Name
select new { f, c };
foreach (var j in formatListJoin)
{
j.c.Label = (string)j.f.ChildNodes[1].Token.Value;
}
//TODO: handle where
AssertEmpty(tree.Root.ChildNodes[1]); //where
var orderByList = tree.Root.ChildNodes[4].ClauseList();
var orderByListJoin = from o in orderByList
join p in properties on o.ChildNodes[0].ToPropertyName() equals p.PropertyName into propertyGroup
from p in propertyGroup.DefaultIfEmpty()
select new { o, p };
foreach (var o in orderByListJoin)
{
if (o.p == null) throw new NotImplementedException("Can only order by identifiers.");
var ascending = true;
if (o.o.ChildNodes.Count == 2)
{
ascending = !string.Equals((string)o.o.ChildNodes[1].Token.Value, "desc", StringComparison.OrdinalIgnoreCase);
}
if (_orderBy == null)
{
if (ascending)
{
_orderBy = data => data.OrderBy(o.p.PropertyName);
}
else
{
_orderBy = data => data.OrderByDescending(o.p.PropertyName);
}
}
else
{
if (ascending)
{
_orderBy = data => _orderBy(data.OrderBy(o.p.PropertyName));
}
else
{
_orderBy = data => _orderBy(data.OrderByDescending(o.p.PropertyName));
}
}
}
}
else
{
throw new QueryParseException("Query parsing resulted in an error.");
}
}
