/// <summary>
/// Parses Group by parse tree, the information is stored in the expression info class.
/// The reason this method is separated from constructor is because it cannot guess whether the
/// clause is a normal group by or a single group group by, thus the group by must always be parsed
/// as the first clause after the Match clause.
/// </summary>
public static void ParseGroupBy(Graph graph, VariableMap variableMap, IGroupByExecutionHelper executionHelper, GroupByNode groupByNode, QueryExpressionInfo exprInfo)
{
if (executionHelper == null || groupByNode == null || variableMap == null || graph == null || exprInfo == null)
{
throw new ArgumentNullException($"Group by results processor, passing null arguments to the constructor.");
}
var groupbyVisitor = new GroupByVisitor(graph.labels, variableMap, exprInfo);
groupbyVisitor.Visit(groupByNode);
executionHelper.IsSetGroupBy = true;
}
/// <summary>
/// Creates a group by object for multigroup group by (defined group by clause).
/// </summary>
/// <param name="graph"> A property graph. </param>
/// <param name="variableMap"> A variable map. </param>
/// <param name="executionHelper"> A group by execution helper. </param>
/// <param name="groupByNode"> A parsed tree of group by expression. </param>
/// <param name="exprInfo"> A query expression information. </param>
public GroupByObject(Graph graph, VariableMap variableMap, IGroupByExecutionHelper executionHelper, GroupByNode groupByNode, QueryExpressionInfo exprInfo)
{
if (executionHelper == null || groupByNode == null || variableMap == null || graph == null || exprInfo == null)
{
throw new ArgumentNullException($"{this.GetType()}, passing null arguments to the constructor.");
}
this.helper = executionHelper;
var groupbyVisitor = new GroupByVisitor(graph.labels, variableMap, exprInfo);
groupbyVisitor.Visit(groupByNode);
this.hashes = groupbyVisitor.GetResult().ToArray();
this.aggregates = exprInfo.Aggregates;
this.helper.IsSetGroupBy = true;
}