/// <summary>
/// Get the result table of the given pattern group
/// </summary>
internal static void CombinePatterns(RDFConstructQuery query, RDFPatternGroup patternGroup)
{
if (patternGroup.Patterns.Any())
{
//Populate pattern group result table
DataTable patternGroupResultTable = RDFQueryEngine.CombineTables(query.PatternResultTables[patternGroup], false);
//Add it to the list of pattern group result tables
query.PatternGroupResultTables.Add(patternGroup, patternGroupResultTable);
//Populate its metadata
query.PatternGroupResultTables[patternGroup].TableName = patternGroup.ToString();
if (!query.PatternGroupResultTables[patternGroup].ExtendedProperties.ContainsKey("IsOptional"))
{
query.PatternGroupResultTables[patternGroup].ExtendedProperties.Add("IsOptional", patternGroup.IsOptional);
}
else
{
query.PatternGroupResultTables[patternGroup].ExtendedProperties["IsOptional"] = patternGroup.IsOptional;
}
if (!query.PatternGroupResultTables[patternGroup].ExtendedProperties.ContainsKey("JoinAsUnion"))
{
query.PatternGroupResultTables[patternGroup].ExtendedProperties.Add("JoinAsUnion", patternGroup.JoinAsUnion);
}
else
{
query.PatternGroupResultTables[patternGroup].ExtendedProperties["JoinAsUnion"] = patternGroup.JoinAsUnion;
}
}
}
/// <summary>
/// Apply the filters of the given pattern group to its result table
/// </summary>
internal static void ApplyFilters(RDFConstructQuery query, RDFPatternGroup patternGroup)
{
if (patternGroup.Patterns.Any() && patternGroup.Filters.Any())
{
DataTable filteredTable = query.PatternGroupResultTables[patternGroup].Clone();
IEnumerator rowsEnum = query.PatternGroupResultTables[patternGroup].Rows.GetEnumerator();
//Iterate the rows of the pattern group's result table
Boolean keepRow = false;
while (rowsEnum.MoveNext())
{
//Apply the pattern group's filters on the row
keepRow = true;
IEnumerator <RDFFilter> filtersEnum = patternGroup.Filters.GetEnumerator();
while (keepRow && filtersEnum.MoveNext())
{
keepRow = filtersEnum.Current.ApplyFilter((DataRow)rowsEnum.Current, false);
}
//If the row has passed all the filters, keep it in the filtered result table
if (keepRow)
{
DataRow newRow = filteredTable.NewRow();
newRow.ItemArray = ((DataRow)rowsEnum.Current).ItemArray;
filteredTable.Rows.Add(newRow);
}
}
//Save the result datatable
query.PatternGroupResultTables[patternGroup] = filteredTable;
}
}
/// <summary>
/// Apply the filters of the given pattern group to its result table
/// </summary>
internal static void ApplyFilters(RDFConstructQuery query, RDFPatternGroup patternGroup) {
if (patternGroup.Patterns.Any() && patternGroup.Filters.Any()) {
DataTable filteredTable = query.PatternGroupResultTables[patternGroup].Clone();
IEnumerator rowsEnum = query.PatternGroupResultTables[patternGroup].Rows.GetEnumerator();
//Iterate the rows of the pattern group's result table
Boolean keepRow = false;
while (rowsEnum.MoveNext()) {
//Apply the pattern group's filters on the row
keepRow = true;
IEnumerator<RDFFilter> filtersEnum = patternGroup.Filters.GetEnumerator();
while (keepRow && filtersEnum.MoveNext()) {
keepRow = filtersEnum.Current.ApplyFilter((DataRow)rowsEnum.Current, false);
}
//If the row has passed all the filters, keep it in the filtered result table
if (keepRow) {
DataRow newRow = filteredTable.NewRow();
newRow.ItemArray = ((DataRow)rowsEnum.Current).ItemArray;
filteredTable.Rows.Add(newRow);
}
}
//Save the result datatable
query.PatternGroupResultTables[patternGroup] = filteredTable;
}
}
/// <summary>
/// Apply the query modifiers to the query result table
/// </summary>
internal static DataTable ApplyModifiers(RDFConstructQuery query, DataTable table)
{
String tablenameBak = table.TableName;
//Apply the DISTINCT modifier
table = new RDFDistinctModifier().ApplyModifier(table);
//Apply the OFFSET modifier
table = query.Modifiers.Where(m => m is RDFOffsetModifier)
.Aggregate(table, (current, modifier) => modifier.ApplyModifier(current));
//Apply the LIMIT modifier
table = query.Modifiers.Where(m => m is RDFLimitModifier)
.Aggregate(table, (current, modifier) => modifier.ApplyModifier(current));
table.TableName = tablenameBak;
return(table);
}
/// <summary>
/// Get the intermediate result tables of the given pattern group
/// </summary>
internal static void EvaluatePatterns(RDFConstructQuery query, RDFPatternGroup patternGroup, Object graphOrStore)
{
query.PatternResultTables[patternGroup] = new List <DataTable>();
//Iterate over the patterns of the pattern group
foreach (RDFPattern pattern in patternGroup.Patterns)
{
//Apply the pattern to the graph/store
DataTable patternResultsTable = graphOrStore is RDFGraph?RDFQueryEngine.ApplyPattern(pattern, (RDFGraph)graphOrStore)
: RDFQueryEngine.ApplyPattern(pattern, (RDFStore)graphOrStore);
//Set the name and the optionality metadata of the result datatable
patternResultsTable.TableName = pattern.ToString();
patternResultsTable.ExtendedProperties.Add("IsOptional", pattern.IsOptional);
patternResultsTable.ExtendedProperties.Add("JoinAsUnion", pattern.JoinAsUnion);
//Save the result datatable
query.PatternResultTables[patternGroup].Add(patternResultsTable);
}
}
/// <summary>
/// Get the intermediate result tables of the given pattern group
/// </summary>
internal static void EvaluatePatterns(RDFConstructQuery query, RDFPatternGroup patternGroup, Object graphOrStore) {
query.PatternResultTables[patternGroup] = new List<DataTable>();
//Iterate over the patterns of the pattern group
foreach (RDFPattern pattern in patternGroup.Patterns) {
//Apply the pattern to the graph/store
DataTable patternResultsTable = graphOrStore is RDFGraph ? RDFQueryEngine.ApplyPattern(pattern, (RDFGraph)graphOrStore)
: RDFQueryEngine.ApplyPattern(pattern, (RDFStore)graphOrStore);
//Set the name and the optionality metadata of the result datatable
patternResultsTable.TableName = pattern.ToString();
patternResultsTable.ExtendedProperties.Add("IsOptional", pattern.IsOptional);
patternResultsTable.ExtendedProperties.Add("JoinAsUnion", pattern.JoinAsUnion);
//Save the result datatable
query.PatternResultTables[patternGroup].Add(patternResultsTable);
}
}
/// <summary>
/// Prints the string representation of a SPARQL CONSTRUCT query
/// </summary>
internal static String PrintConstructQuery(RDFConstructQuery constructQuery)
{
StringBuilder sb = new StringBuilder();
if (constructQuery != null)
{
#region PREFIXES
if (constructQuery.Prefixes.Any())
{
constructQuery.Prefixes.ForEach(pf =>
{
sb.Append("PREFIX " + pf.NamespacePrefix + ": <" + pf.NamespaceUri + ">\n");
});
sb.Append("\n");
}
#endregion
#region HEADER
#region BEGINCONSTRUCT
sb.Append("CONSTRUCT");
#endregion
#region TEMPLATES
sb.Append("\n{\n");
constructQuery.Templates.ForEach(tp =>
{
String tpString = PrintPattern(tp, constructQuery.Prefixes);
//Remove the Context from the template print (since it is not supported by CONSTRUCT query)
if (tp.Context != null)
{
tpString = tpString.Replace("GRAPH " + tp.Context + " { ", String.Empty).TrimEnd(new Char[] { ' ', '}' });
}
//Remove the Optional indicator from the template print (since it is not supported by CONSTRUCT query)
if (tp.IsOptional)
{
tpString = tpString.Replace("OPTIONAL { ", String.Empty).TrimEnd(new Char[] { ' ', '}' });
}
sb.Append(" " + tpString + " .\n");
});
sb.Append("}\n");
#endregion
#endregion
#region BODY
sb.Append("WHERE {\n");
#region MEMBERS
Boolean printingUnion = false;
List <RDFQueryMember> evaluableQueryMembers = constructQuery.GetEvaluableQueryMembers().ToList();
RDFQueryMember lastQueryMbr = evaluableQueryMembers.LastOrDefault();
foreach (var queryMember in evaluableQueryMembers)
{
#region PATTERNGROUPS
if (queryMember is RDFPatternGroup)
{
//Current pattern group is set as UNION with the next one
if (((RDFPatternGroup)queryMember).JoinAsUnion)
{
//Current pattern group IS NOT the last of the query
//(so UNION keyword must be appended at last)
if (!queryMember.Equals(lastQueryMbr))
{
//Begin a new Union block
if (!printingUnion)
{
printingUnion = true;
sb.Append(" {\n");
}
sb.Append(PrintPatternGroup((RDFPatternGroup)queryMember, 2, true, constructQuery.Prefixes));
sb.Append(" UNION\n");
}
//Current pattern group IS the last of the query
//(so UNION keyword must not be appended at last)
else
{
//End the Union block
if (printingUnion)
{
printingUnion = false;
sb.Append(PrintPatternGroup((RDFPatternGroup)queryMember, 2, true, constructQuery.Prefixes));
sb.Append(" }\n");
}
else
{
sb.Append(PrintPatternGroup((RDFPatternGroup)queryMember, 0, false, constructQuery.Prefixes));
}
}
}
//Current pattern group is set as INTERSECT with the next one
else
{
//End the Union block
if (printingUnion)
{
printingUnion = false;
sb.Append(PrintPatternGroup((RDFPatternGroup)queryMember, 2, true, constructQuery.Prefixes));
sb.Append(" }\n");
}
else
{
sb.Append(PrintPatternGroup((RDFPatternGroup)queryMember, 0, false, constructQuery.Prefixes));
}
}
}
#endregion
#region SUBQUERY
else if (queryMember is RDFQuery)
{
//Merge main query prefixes
constructQuery.Prefixes.ForEach(pf1 => {
if (!((RDFSelectQuery)queryMember).Prefixes.Any(pf2 => pf2.Equals(pf1)))
{
((RDFSelectQuery)queryMember).AddPrefix(pf1);
}
});
//Current subquery is set as UNION with the next one
if (((RDFSelectQuery)queryMember).JoinAsUnion)
{
//Current subquery IS NOT the last of the query
//(so UNION keyword must be appended at last)
if (!queryMember.Equals(lastQueryMbr))
{
//Begin a new Union block
if (!printingUnion)
{
printingUnion = true;
sb.Append(" {\n");
}
sb.Append(PrintSelectQuery((RDFSelectQuery)queryMember, 1, true));
sb.Append(" UNION\n");
}
//Current query IS the last of the query
//(so UNION keyword must not be appended at last)
else
{
//End the Union block
if (printingUnion)
{
printingUnion = false;
sb.Append(PrintSelectQuery((RDFSelectQuery)queryMember, 1, true));
sb.Append(" }\n");
}
else
{
sb.Append(PrintSelectQuery((RDFSelectQuery)queryMember, 1, false));
}
}
}
//Current query is set as INTERSECT with the next one
else
{
//End the Union block
if (printingUnion)
{
printingUnion = false;
sb.Append(PrintSelectQuery((RDFSelectQuery)queryMember, 1, true));
sb.Append(" }\n");
}
else
{
sb.Append(PrintSelectQuery((RDFSelectQuery)queryMember, 1, false));
}
}
}
#endregion
}
#endregion
sb.Append("}");
#endregion
#region FOOTER
#region MODIFIERS
List <RDFModifier> modifiers = constructQuery.GetModifiers().ToList();
// LIMIT/OFFSET
if (modifiers.Any(mod => mod is RDFLimitModifier || mod is RDFOffsetModifier))
{
modifiers.Where(mod => mod is RDFLimitModifier)
.ToList()
.ForEach(lim => { sb.Append("\n"); sb.Append(lim); });
modifiers.Where(mod => mod is RDFOffsetModifier)
.ToList()
.ForEach(off => { sb.Append("\n"); sb.Append(off); });
}
#endregion
#endregion
}
return(sb.ToString());
}
/// <summary>
/// Fills the templates of the given query with data from the given result table
/// </summary>
internal static DataTable FillTemplates(RDFConstructQuery constructQuery, DataTable resultTable)
{
//Create the structure of the result datatable
DataTable result = new DataTable("CONSTRUCT_RESULTS");
result.Columns.Add("SUBJECT", Type.GetType("System.String"));
result.Columns.Add("PREDICATE", Type.GetType("System.String"));
result.Columns.Add("OBJECT", Type.GetType("System.String"));
result.AcceptChanges();
//Initialize working variables
Dictionary <String, String> constructRow = new Dictionary <String, String>();
constructRow.Add("SUBJECT", null);
constructRow.Add("PREDICATE", null);
constructRow.Add("OBJECT", null);
//Iterate on the templates
foreach (RDFPattern tp in constructQuery.Templates.Where(tp => tp.Variables.Count == 0 ||
tp.Variables.TrueForAll(v => resultTable.Columns.Contains(v.ToString()))))
{
#region GROUND TEMPLATE
//Check if the template is ground, so represents an explicit triple to be added as-is
if (tp.Variables.Count == 0)
{
constructRow["SUBJECT"] = tp.Subject.ToString();
constructRow["PREDICATE"] = tp.Predicate.ToString();
constructRow["OBJECT"] = tp.Object.ToString();
RDFQueryUtilities.AddRow(result, constructRow);
continue;
}
#endregion
#region NON-GROUND TEMPLATE
//Iterate the result datatable's rows to construct the triples of the current template
IEnumerator rowsEnum = resultTable.Rows.GetEnumerator();
while (rowsEnum.MoveNext())
{
#region SUBJECT
//Subject of the template is a variable
if (tp.Subject is RDFVariable)
{
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template subject
if (((DataRow)rowsEnum.Current).IsNull(tp.Subject.ToString()))
{
continue;
}
RDFPatternMember subj = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Subject.ToString()].ToString());
//Row contains a literal in position of the variable corresponding to the template subject
if (subj is RDFLiteral)
{
continue;
}
//Row contains a resource in position of the variable corresponding to the template subject
constructRow["SUBJECT"] = subj.ToString();
}
//Subject of the template is a resource
else
{
constructRow["SUBJECT"] = tp.Subject.ToString();
}
#endregion
#region PREDICATE
//Predicate of the template is a variable
if (tp.Predicate is RDFVariable)
{
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template predicate
if (((DataRow)rowsEnum.Current).IsNull(tp.Predicate.ToString()))
{
continue;
}
RDFPatternMember pred = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Predicate.ToString()].ToString());
//Row contains a blank resource or a literal in position of the variable corresponding to the template predicate
if ((pred is RDFResource && ((RDFResource)pred).IsBlank) || pred is RDFLiteral)
{
continue;
}
//Row contains a non-blank resource in position of the variable corresponding to the template predicate
constructRow["PREDICATE"] = pred.ToString();
}
//Predicate of the template is a resource
else
{
constructRow["PREDICATE"] = tp.Predicate.ToString();
}
#endregion
#region OBJECT
//Object of the template is a variable
if (tp.Object is RDFVariable)
{
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template object
if (((DataRow)rowsEnum.Current).IsNull(tp.Object.ToString()))
{
continue;
}
RDFPatternMember obj = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Object.ToString()].ToString());
//Row contains a resource or a literal in position of the variable corresponding to the template object
constructRow["OBJECT"] = obj.ToString();
}
//Object of the template is a resource or a literal
else
{
constructRow["OBJECT"] = tp.Object.ToString();
}
#endregion
//Insert the triple into the final table
RDFQueryUtilities.AddRow(result, constructRow);
}
#endregion
}
return(result);
}
/// <summary>
/// Apply the query modifiers to the query result table
/// </summary>
internal static DataTable ApplyModifiers(RDFConstructQuery query, DataTable table) {
String tablenameBak = table.TableName;
//Apply the DISTINCT modifier
table = new RDFDistinctModifier().ApplyModifier(table);
//Apply the OFFSET modifier
table = query.Modifiers.Where(m => m is RDFOffsetModifier)
.Aggregate(table, (current, modifier) => modifier.ApplyModifier(current));
//Apply the LIMIT modifier
table = query.Modifiers.Where(m => m is RDFLimitModifier)
.Aggregate(table, (current, modifier) => modifier.ApplyModifier(current));
table.TableName = tablenameBak;
return table;
}
/// <summary>
/// Fills the templates of the given query with data from the given result table
/// </summary>
internal static DataTable FillTemplates(RDFConstructQuery constructQuery, DataTable resultTable) {
//Create the structure of the result datatable
DataTable result = new DataTable("CONSTRUCT_RESULTS");
result.Columns.Add("SUBJECT", Type.GetType("System.String"));
result.Columns.Add("PREDICATE", Type.GetType("System.String"));
result.Columns.Add("OBJECT", Type.GetType("System.String"));
result.AcceptChanges();
//Initialize working variables
Dictionary<String, String> constructRow = new Dictionary<String, String>();
constructRow.Add("SUBJECT", null);
constructRow.Add("PREDICATE", null);
constructRow.Add("OBJECT", null);
//Iterate on the templates
foreach (RDFPattern tp in constructQuery.Templates.Where(tp => tp.Variables.Count == 0 ||
tp.Variables.TrueForAll(v => resultTable.Columns.Contains(v.ToString())))) {
#region GROUND TEMPLATE
//Check if the template is ground, so represents an explicit triple to be added as-is
if (tp.Variables.Count == 0) {
constructRow["SUBJECT"] = tp.Subject.ToString();
constructRow["PREDICATE"] = tp.Predicate.ToString();
constructRow["OBJECT"] = tp.Object.ToString();
RDFQueryUtilities.AddRow(result, constructRow);
continue;
}
#endregion
#region NON-GROUND TEMPLATE
//Iterate the result datatable's rows to construct the triples of the current template
IEnumerator rowsEnum = resultTable.Rows.GetEnumerator();
while (rowsEnum.MoveNext()) {
#region SUBJECT
//Subject of the template is a variable
if (tp.Subject is RDFVariable) {
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template subject
if (((DataRow)rowsEnum.Current).IsNull(tp.Subject.ToString())) {
continue;
}
RDFPatternMember subj = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Subject.ToString()].ToString());
//Row contains a literal in position of the variable corresponding to the template subject
if (subj is RDFLiteral) {
continue;
}
//Row contains a resource in position of the variable corresponding to the template subject
constructRow["SUBJECT"] = subj.ToString();
}
//Subject of the template is a resource
else {
constructRow["SUBJECT"] = tp.Subject.ToString();
}
#endregion
#region PREDICATE
//Predicate of the template is a variable
if (tp.Predicate is RDFVariable) {
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template predicate
if (((DataRow)rowsEnum.Current).IsNull(tp.Predicate.ToString())) {
continue;
}
RDFPatternMember pred = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Predicate.ToString()].ToString());
//Row contains a blank resource or a literal in position of the variable corresponding to the template predicate
if ((pred is RDFResource && ((RDFResource)pred).IsBlank) || pred is RDFLiteral) {
continue;
}
//Row contains a non-blank resource in position of the variable corresponding to the template predicate
constructRow["PREDICATE"] = pred.ToString();
}
//Predicate of the template is a resource
else {
constructRow["PREDICATE"] = tp.Predicate.ToString();
}
#endregion
#region OBJECT
//Object of the template is a variable
if (tp.Object is RDFVariable) {
//Check if the template must be skipped, in order to not produce illegal triples
//Row contains an unbound value in position of the variable corresponding to the template object
if (((DataRow)rowsEnum.Current).IsNull(tp.Object.ToString())) {
continue;
}
RDFPatternMember obj = RDFQueryUtilities.ParseRDFPatternMember(((DataRow)rowsEnum.Current)[tp.Object.ToString()].ToString());
//Row contains a resource or a literal in position of the variable corresponding to the template object
constructRow["OBJECT"] = obj.ToString();
}
//Object of the template is a resource or a literal
else {
constructRow["OBJECT"] = tp.Object.ToString();
}
#endregion
//Insert the triple into the final table
RDFQueryUtilities.AddRow(result, constructRow);
}
#endregion
}
return result;
}
/// <summary>
/// Get the result table of the given pattern group
/// </summary>
internal static void CombinePatterns(RDFConstructQuery query, RDFPatternGroup patternGroup) {
if (patternGroup.Patterns.Any()) {
//Populate pattern group result table
DataTable patternGroupResultTable = RDFQueryEngine.CombineTables(query.PatternResultTables[patternGroup], false);
//Add it to the list of pattern group result tables
query.PatternGroupResultTables.Add(patternGroup, patternGroupResultTable);
//Populate its metadata
query.PatternGroupResultTables[patternGroup].TableName = patternGroup.ToString();
if (!query.PatternGroupResultTables[patternGroup].ExtendedProperties.ContainsKey("IsOptional")) {
query.PatternGroupResultTables[patternGroup].ExtendedProperties.Add("IsOptional", patternGroup.IsOptional);
}
else {
query.PatternGroupResultTables[patternGroup].ExtendedProperties["IsOptional"] = patternGroup.IsOptional;
}
if (!query.PatternGroupResultTables[patternGroup].ExtendedProperties.ContainsKey("JoinAsUnion")) {
query.PatternGroupResultTables[patternGroup].ExtendedProperties.Add("JoinAsUnion", patternGroup.JoinAsUnion);
}
else {
query.PatternGroupResultTables[patternGroup].ExtendedProperties["JoinAsUnion"] = patternGroup.JoinAsUnion;
}
}
}