/// <summary>
/// Parser method which parses a Binding Object which occurs in the array of Bindings
/// </summary>
private void ParseBinding(SparqlJsonParserContext context, bool headSeen)
{
//Can we read some properties
if (context.Input.Read())
{
SparqlResult result = new SparqlResult();
while (context.Input.TokenType != JsonToken.EndObject)
{
if (context.Input.TokenType == JsonToken.PropertyName)
{
//Each Property Name should be for a variable
this.ParseBoundVariable(context, context.Input.Value.ToString(), result, headSeen);
}
else
{
throw Error(context, "Unexpected Token '" + context.Input.TokenType + "' with value '" + context.Input.Value + "' encountered, expected a Property Name giving the Binding for a Variable for this Result");
}
//Get Next Token
if (!context.Input.Read())
{
throw new RdfParseException("Unexpected End of Input while trying to parse a Binding Object");
}
}
//Check that all Variables are bound for a given result binding nulls where appropriate
foreach (String v in context.Variables)
{
if (!result.HasValue(v))
{
result.SetValue(v, null);
}
}
//Add to Results
result.SetVariableOrdering(context.Variables);
if (!context.Handler.HandleResult(result))
{
ParserHelper.Stop();
}
}
else
{
throw new RdfParseException("Unexpected End of Input while trying to parse a Binding Object");
}
}
private void TryParseResultRow(TokenisingResultParserContext context)
{
IToken next = context.Tokens.Peek();
if (next.TokenType == Token.EOF)
{
context.Tokens.Dequeue();
return;
}
bool allowEOL = true, expectTab = false;
int v = 0;
SparqlResult result = new SparqlResult();
while (true)
{
next = context.Tokens.Dequeue();
switch (next.TokenType)
{
case Token.URI:
if (expectTab)
{
throw ParserHelper.Error("Unexpected URI, expected a Tab between RDF Terms", next);
}
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
INode uri = ParserHelper.TryResolveUri(context, next);
result.SetValue(context.Variables[v], uri);
v++;
allowEOL = true;
expectTab = true;
break;
case Token.BLANKNODEWITHID:
if (expectTab)
{
throw ParserHelper.Error("Unexpected Blank Node, expected a Tab between RDF Terms", next);
}
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
INode blank = context.Handler.CreateBlankNode(next.Value.Substring(2));
result.SetValue(context.Variables[v], blank);
v++;
allowEOL = true;
expectTab = true;
break;
case Token.LITERAL:
case Token.LONGLITERAL:
case Token.PLAINLITERAL:
if (expectTab)
{
throw ParserHelper.Error("Unexpected Blank Node, expected a Tab between RDF Terms", next);
}
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
INode lit = TryParseLiteral(context, next);
result.SetValue(context.Variables[v], lit);
v++;
allowEOL = true;
expectTab = true;
break;
case Token.EOL:
if (allowEOL)
{
break;
}
else
{
if (v == context.Variables.Count - 1)
{
// If this is the last expected term then this must be an empty term
v++;
break;
}
throw ParserHelper.Error("Unexpected End of Line, expected a RDF Term Token", next);
}
case Token.TAB:
if (!expectTab)
{
// This is an empty field
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
v++;
}
expectTab = false;
allowEOL = false;
break;
case Token.EOF:
if (!allowEOL)
{
throw ParserHelper.Error("Unexpected EOF, expected another RDF Term for the Result Row", next);
}
break;
default:
throw ParserHelper.Error("Unexpected Token '" + next.GetType().ToString() + "' encountered", next);
}
// Stop when we've hit the End of the Line/File
if (next.TokenType == Token.EOL || next.TokenType == Token.EOF)
{
break;
}
}
if (v < context.Variables.Count)
{
throw ParserHelper.Error("Too few RDF Terms, got " + v + " but expected " + context.Variables.Count, next);
}
result.SetVariableOrdering(context.Variables);
if (!context.Handler.HandleResult(result))
{
ParserHelper.Stop();
}
}
private void TryParseResultRow(TokenisingResultParserContext context)
{
IToken next = context.Tokens.Peek();
if (next.TokenType == Token.EOF)
{
context.Tokens.Dequeue();
return;
}
bool allowEOL = true, expectComma = false;
int v = 0;
SparqlResult result = new SparqlResult();
while (true)
{
next = context.Tokens.Dequeue();
switch (next.TokenType)
{
case Token.BLANKNODEWITHID:
if (expectComma)
{
throw ParserHelper.Error("Unexpected Blank Node, expected a comma between RDF Terms", next);
}
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
INode blank = context.Handler.CreateBlankNode(next.Value.Substring(2));
result.SetValue(context.Variables[v], blank);
v++;
allowEOL = true;
expectComma = true;
break;
case Token.LITERAL:
case Token.PLAINLITERAL:
if (expectComma)
{
throw ParserHelper.Error("Unexpected Blank Node, expected a comma between RDF Terms", next);
}
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
// Try and guess what kind of term this is
String lexicalForm = next.Value;
INode value;
if (lexicalForm.StartsWith("http://") || lexicalForm.StartsWith("https://") || lexicalForm.StartsWith("mailto:") || lexicalForm.StartsWith("ftp://"))
{
try
{
// Guessing a URI if starts with common URI prefix
value = ParserHelper.TryResolveUri(context, next);
}
catch
{
// If invalid URI fall back to treating as literal
value = context.Handler.CreateLiteralNode(lexicalForm);
}
}
else
{
value = context.Handler.CreateLiteralNode(lexicalForm);
}
result.SetValue(context.Variables[v], value);
v++;
allowEOL = true;
expectComma = true;
break;
case Token.EOL:
if (allowEOL)
{
break;
}
else
{
if (v == context.Variables.Count - 1)
{
// If this is the last expected term then this must be an empty term
v++;
break;
}
throw ParserHelper.Error("Unexpected End of Line, expected a RDF Term Token", next);
}
case Token.COMMA:
if (!expectComma)
{
// This is an empty field
if (v >= context.Variables.Count)
{
throw ParserHelper.Error("Too many RDF Terms, only expecting " + context.Variables.Count + " terms", next);
}
v++;
}
expectComma = false;
allowEOL = false;
break;
case Token.EOF:
if (!allowEOL)
{
throw ParserHelper.Error("Unexpected EOF, expected another RDF Term for the Result Row", next);
}
break;
default:
throw ParserHelper.Error("Unexpected Token '" + next.GetType().ToString() + "' encountered", next);
}
// Stop when we've hit the End of the Line/File
if (next.TokenType == Token.EOL || next.TokenType == Token.EOF)
{
break;
}
}
result.SetVariableOrdering(context.Variables);
if (!context.Handler.HandleResult(result))
{
ParserHelper.Stop();
}
}
/// <summary>
/// Parses the XML Result Set format into a set of SPARQLResult objects
/// </summary>
/// <param name="context">Parser Context</param>
private void Parse(SparqlXmlParserContext context)
{
try
{
context.Handler.StartResults();
// Get the Document Element and check it's a Sparql element
if (!context.Input.Read())
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as it was not possible to read a document element from the input");
}
while (context.Input.NodeType != XmlNodeType.Element)
{
if (!context.Input.Read())
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as it was not possible to read a document element from the input");
}
}
if (!context.Input.Name.Equals("sparql"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set from the provided XML since the Document Element is not a <sparql> element!");
}
// Go through it's attributes and check the Namespace is specified
bool nsfound = false;
if (context.Input.HasAttributes)
{
for (int i = 0; i < context.Input.AttributeCount; i++)
{
context.Input.MoveToNextAttribute();
if (context.Input.Name.Equals("xmlns"))
{
if (!context.Input.Value.Equals(SparqlSpecsHelper.SparqlNamespace))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <sparql> element has an incorrect Namespace!");
}
else
{
nsfound = true;
}
}
}
}
if (!nsfound)
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <sparql> element fails to specify the SPARQL Namespace!");
}
// Get the Variables from the Header
if (!context.Input.Read())
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as could not read a <head> element from the input");
}
if (!context.Input.Name.Equals("head"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the first Child Node of the <sparql> element is not the required <head> element!");
}
// Only parser <variable> and <link> elements if not an empty <head /> element
if (!context.Input.IsEmptyElement)
{
while (context.Input.Read())
{
// Stop reading when we hit the </head>
if (context.Input.NodeType == XmlNodeType.EndElement && context.Input.Name.Equals("head"))
{
break;
}
// Looking for <variable> elements
if (context.Input.Name.Equals("variable"))
{
// Should only have 1 attribute
if (context.Input.AttributeCount != 1)
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since a <variable> element has too few/many attributes, only a 'name' attribute should be present!");
}
else
{
// Add the Variable to the list
context.Input.MoveToNextAttribute();
if (!context.Handler.HandleVariable(context.Input.Value))
{
ParserHelper.Stop();
}
context.Variables.Add(context.Input.Value);
}
}
else if (context.Input.Name.Equals("link"))
{
// Not bothered about <link> elements
}
else
{
// Some unexpected element
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <head> contains an unexpected element <" + context.Input.Name + ">!");
}
}
}
if (!context.Input.Name.Equals("head"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as reached the end of the input before the closing </head> element was found");
}
// Look at the <results> or <boolean> element
if (!context.Input.Read())
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as could not read a <results> element from the input");
}
if (context.Input.Name.Equals("results"))
{
// Only parser <result> elements if it's not an empty <results /> element
if (!context.Input.IsEmptyElement)
{
while (context.Input.Read())
{
// Stop reading when we hit the </results>
if (context.Input.NodeType == XmlNodeType.EndElement && context.Input.Name.Equals("results"))
{
break;
}
// Must be a <result> element
if (!context.Input.Name.Equals("result"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <results> element contains an unexpected element <" + context.Input.Name + ">!");
}
// Empty Elements generate an Empty Result
if (context.Input.IsEmptyElement)
{
if (!context.Handler.HandleResult(new SparqlResult()))
{
ParserHelper.Stop();
}
continue;
}
// Get the values of each Binding
String var;
INode value;
SparqlResult result = new SparqlResult();
while (context.Input.Read())
{
// Stop reading when we hit the </binding>
if (context.Input.NodeType == XmlNodeType.EndElement && context.Input.Name.Equals("result"))
{
break;
}
// Must be a <binding> element
if (!context.Input.Name.Equals("binding"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since a <result> element contains an unexpected element <" + context.Input.Name + ">!");
}
// Must have only 1 attribute
if (context.Input.AttributeCount != 1)
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since a <binding> element has too few/many attributes, only a 'name' attribute should be present!");
}
// Get the Variable this is a binding for and its Value
context.Input.MoveToNextAttribute();
var = context.Input.Value;
if (!context.Input.Read())
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as reached the end of input when the contents of a <binding> element was expected");
}
value = ParseValue(context);
// Check that the Variable was defined in the Header
if (!context.Variables.Contains(var))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since a <binding> element attempts to bind a value to the variable '" + var + "' which is not defined in the <head> by a <variable> element!");
}
// Set the Variable to the Value
result.SetValue(var, value);
}
// Check that all Variables are bound for a given result binding nulls where appropriate
foreach (String v in context.Variables)
{
if (!result.HasValue(v))
{
result.SetValue(v, null);
}
}
if (!context.Input.Name.Equals("result"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as reached the end of the input before a closing </result> element was found");
}
// Add to results set
result.SetVariableOrdering(context.Variables);
if (!context.Handler.HandleResult(result))
{
ParserHelper.Stop();
}
}
}
if (!context.Input.Name.Equals("results"))
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set as reached the end of the input before the closing </results> element was found");
}
}
else if (context.Input.Name.Equals("boolean"))
{
// Can't be any <variable> elements
if (context.Variables.Count > 0)
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <boolean> element is specified but the <head> contained one/more <variable> elements which is not permitted!");
}
try
{
// Get the value of the <boolean> element as a Boolean
Boolean b = Boolean.Parse(context.Input.ReadInnerXml());
context.Handler.HandleBooleanResult(b);
}
catch (Exception)
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the <boolean> element contained a value that could not be understood as a Boolean value!");
}
}
else
{
throw new RdfParseException("Unable to Parse a SPARQL Result Set since the second Child Node of the <sparql> element is not the required <results> or <boolean> element!");
}
context.Handler.EndResults(true);
}
catch (RdfParsingTerminatedException)
{
context.Handler.EndResults(true);
}
catch
{
// Some other Error
context.Handler.EndResults(false);
throw;
}
}
