/// <summary>
/// A root node of the parse tree.
/// Jumps to the node under the root.
/// All patterns must have at least one match node.
/// There is always at least one pattern.
/// </summary>
public void Visit(MatchNode node)
{
result.Add(currentPattern);
node.next.Accept(this);
for (int i = 0; i < result.Count; i++)
{
if (result[i].GetCount() <= 0)
{
throw new ArgumentException($"{this.GetType()}, failed to parse match expr.");
}
}
}
/// <summary>
/// Parsing a match expression, chains of vertex -> edge -> vertex expressions.
/// Match -> MATCH MatchTerm (, MatchTerm)*
/// MatchTerm -> Vertex (Edge Vertex)*
/// Vertex -> (MatchVariable)
/// Edge -> (EmptyAnyEdge|EmptyOutEdge|EmptyInEdge|AnyEdge|InEdge|OutEdge)
/// EmptyAnyEdge -> -
/// EmptyOutEdge -> o-
/// EmptyInEdge -> ->
/// AnyEdge -> -[MatchVariable]-
/// InEdge -> o-[MatchVariable]-
/// OutEdge -> -[MatchVariable]->
/// MatchVariable -> (VariableNameReference)?(:TableType)?
/// TableType -> IDENTIFIER
/// VariableNameReference -> IDENTIFIER
/// </summary>
/// <returns> A tree representation of Match expression. </returns>
static public MatchNode ParseMatch(ref int position, List <Token> tokens)
{
MatchNode matchNode = new MatchNode();
// We expect after reading Select expr that the position is set on the Match token.
if (!CheckToken(position, Token.TokenType.Match, tokens))
{
ThrowError("Match parser", "Failed to find MATCH token.", position, tokens);
}
else
{
position++;
Node node = ParseVertex(ref position, tokens);
if (node == null)
{
ThrowError("Match parser", "Failed to parse Match expression.", position, tokens);
}
matchNode.AddNext(node);
}
return(matchNode);
}
public void Visit(MatchNode node)
{
throw new NotImplementedException();
}
/// <summary>
/// Creates Streamed Match object.
/// </summary>
/// <param name="graph"> Graph to conduct a query on. </param>
/// <param name="variableMap"> Empty map of variables. </param>
/// <param name="executionHelper"> Match execution helper. </param>
/// <param name="matchNode"> Parse tree of match expression. </param>
/// <param name="exprInfo"> A query expression information. </param>
public MatchObjectStreamed(Graph graph, VariableMap variableMap, IMatchExecutionHelper executionHelper, MatchNode matchNode, QueryExpressionInfo exprInfo)
{
if (executionHelper == null || matchNode == null || variableMap == null || graph == null)
{
throw new ArgumentNullException($"{this.GetType()}, passing null arguments to the constructor.");
}
this.helper = executionHelper;
MatchVisitor matchVisitor = new MatchVisitor(graph.nodeTables, graph.edgeTables);
matchNode.Accept(matchVisitor);
//Create real pattern and variableMap
var result = matchVisitor.GetResult();
this.CheckParsedPatternCorrectness(result);
// Create matcher and pattern based on the name of matcher and pattern
// Change if necessary
this.pattern = MatchFactory.CreatePattern(helper.ParallelPatternMatcherName, helper.PatternName, variableMap, result);
this.matcher = (IPatternMatcherStreamed)MatchFactory.CreateMatcher(helper.ParallelPatternMatcherName, pattern, graph, executionHelper);
}
/// <summary>
/// Creates a Match object.
/// </summary>
/// <param name="graph"> A graph to conduct a query on. </param>
/// <param name="variableMap"> An empty map of variables. </param>
/// <param name="executionHelper"> A match execution helper. </param>
/// <param name="matchNode"> A parse tree of match expression. </param>
/// <param name="exprInfo"> A query expression information. </param>
public MatchObject(Graph graph, VariableMap variableMap, IMatchExecutionHelper executionHelper, MatchNode matchNode, QueryExpressionInfo exprInfo)
{
if (executionHelper == null || matchNode == null || variableMap == null || graph == null)
{
throw new ArgumentNullException($"{this.GetType()}, passing null arguments to the constructor.");
}
this.helper = executionHelper;
MatchVisitor matchVisitor = new MatchVisitor(graph.nodeTables, graph.edgeTables);
matchNode.Accept(matchVisitor);
// Create real pattern and variableMap.
var result = matchVisitor.GetResult();
this.CheckParsedPatternCorrectness(result);
// Create matcher and pattern based on the name of matcher and pattern.
// Change if necessary .
this.pattern = MatchFactory.CreatePattern(helper.ParallelPatternMatcherName, helper.PatternName, variableMap, result);
// Now we have got enough information about results.
// After creating pattern the variable map is filled and we know extend of the results.
this.queryResults = new MatchFixedResults(this.helper.FixedArraySize, variableMap.GetCount(), executionHelper.ThreadCount);
this.matcher = MatchFactory.CreateMatcher(helper.ParallelPatternMatcherName, pattern, graph, this.queryResults, executionHelper);
}