public static bool CanOptimizeFilter(Expression expression, SparqlQueryBuilder queryBuilder)
{
var optimisationChecker = new SparqlGeneratorWhereExpressionOptimisationVisitor(queryBuilder);
var visitResult = optimisationChecker.VisitExpression(expression);
return(visitResult is BooleanFlagExpression && ((BooleanFlagExpression)visitResult).Value);
}
private SparqlGeneratorWhereExpressionTreeVisitor(SparqlQueryBuilder queryBuilder, bool optimizeFilter, bool isBoolean)
: base(queryBuilder)
{
QueryBuilder = queryBuilder;
_filterWriter = new FilterWriter(this, queryBuilder, new StringBuilder());
_optimizeFilter = optimizeFilter;
_inBooleanExpression = isBoolean;
}
public static void GetSparqlExpression(Expression expression, SparqlQueryBuilder queryBuilder)
{
var visitor = new SparqlGeneratorSelectExpressionTreeVisitor(queryBuilder);
var resultExpression = visitor.VisitExpression(expression);
if (resultExpression is SelectVariableNameExpression)
{
queryBuilder.AddSelectVariable((resultExpression as SelectVariableNameExpression).Name);
}
}
public static Expression GetSparqlExpression(Expression expression, SparqlQueryBuilder queryBuilder)
{
var visitor = new SparqlGeneratorWhereExpressionTreeVisitor(queryBuilder);
var returnedExpression = visitor.VisitExpression(expression);
if (returnedExpression is SelectVariableNameExpression && expression.Type.Equals(typeof(bool)))
{
var svn = (SelectVariableNameExpression)returnedExpression;
// Single boolean member expression requires a special case addition to the filter
queryBuilder.AddFilterExpression("(?" + svn.Name + " = true)");
}
queryBuilder.AddFilterExpression(visitor.FilterExpression);
return(returnedExpression);
}
public static Expression GetSparqlExpression(Expression expression, SparqlQueryBuilder queryBuilder, bool filterOptimizationEnabled)
{
var canOptimizeFilter = filterOptimizationEnabled && CanOptimizeFilter(expression, queryBuilder);
var visitor = new SparqlGeneratorWhereExpressionTreeVisitor(queryBuilder, canOptimizeFilter, expression.Type == typeof(bool));
var returnedExpression = visitor.VisitExpression(expression);
var svn = returnedExpression as SelectVariableNameExpression;
if (svn != null && expression.Type == typeof(bool))
{
// Single boolean member expression requires a special case addition to the filter
queryBuilder.AddFilterExpression("(?" + svn.Name + " = true)");
}
queryBuilder.AddFilterExpression(visitor.FilterExpression);
return(returnedExpression);
}
public static void GetSparqlExpression(Expression expression, SparqlQueryBuilder queryBuilder)
{
var visitor = new SparqlGeneratorSelectExpressionTreeVisitor(queryBuilder);
var resultExpression = visitor.VisitExpression(expression);
if (resultExpression is SelectIdentifierVariableNameExpression)
{
var selectId = resultExpression as SelectIdentifierVariableNameExpression;
var selectVar = queryBuilder.NextVariable();
queryBuilder.AddBindExpression("STRAFTER(STR(?" + selectId.Name + "), " + SparqlQueryBuilder.QuoteLiteralString(selectId.IdentifierPrefix) + ")", selectVar);
queryBuilder.AddSelectVariable(selectVar);
}
else if (resultExpression is SelectVariableNameExpression)
{
queryBuilder.AddSelectVariable((resultExpression as SelectVariableNameExpression).Name);
}
}
private SparqlGeneratorWhereExpressionTreeVisitor(SparqlQueryBuilder queryBuilder) : base(queryBuilder)
{
QueryBuilder = queryBuilder;
_filterWriter = new FilterWriter(this, queryBuilder, new StringBuilder());
}
public FilterWriter(ExpressionTreeVisitorBase parentVisitor, SparqlQueryBuilder queryBuilder, StringBuilder filterExpressionBuilder) : base(queryBuilder)
{
_parent = parentVisitor;
_filterExpressionBuilder = filterExpressionBuilder;
}
SparqlGeneratorQueryModelVisitor(EntityContext context)
{
_context = context;
_queryBuilder = new SparqlQueryBuilder(context);
}
protected ExpressionTreeVisitorBase(SparqlQueryBuilder queryBuilder)
{
QueryBuilder = queryBuilder;
}
private SparqlGeneratorSelectExpressionTreeVisitor(SparqlQueryBuilder queryBuilder) : base(queryBuilder)
{
_queryBuilder = queryBuilder;
}
public SparqlGeneratorWhereExpressionOptimisationVisitor(SparqlQueryBuilder queryBuilder)
{
_queryBuilder = queryBuilder;
}
protected override Expression VisitSubQueryExpression(SubQueryExpression expression)
{
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is ContainsResultOperator)
{
var contains = (ContainsResultOperator)expression.QueryModel.ResultOperators[0];
if (expression.QueryModel.MainFromClause.FromExpression.NodeType == ExpressionType.Constant &&
contains.Item is MemberExpression)
{
var memberExpression = (MemberExpression)contains.Item;
var itemExpression = VisitExpression(contains.Item);
var varNameExpression = itemExpression as SelectVariableNameExpression;
if (varNameExpression != null)
{
if (IsIdInArraySubQuery(memberExpression, expression.QueryModel.MainFromClause.FromExpression))
{
var varName = varNameExpression.Name;
// The subquery is a filter on a resource IRI
// It is more efficient to use a UNION of BIND triple patterns than a FILTER
var values =
((ConstantExpression)expression.QueryModel.MainFromClause.FromExpression).Value as
IEnumerable;
if (values != null)
{
var identifierProperty = memberExpression.Member as PropertyInfo;
QueryBuilder.StartUnion();
foreach (var value in values)
{
QueryBuilder.StartUnionElement();
QueryBuilder.AddBindExpression(
"<" + QueryBuilder.Context.MapIdToUri(identifierProperty, value.ToString()) +
">", varName);
QueryBuilder.EndUnionElement();
}
QueryBuilder.EndUnion();
return(expression);
}
return(base.VisitSubQueryExpression(expression));
}
else
{
// The subquery is a filter on a resource property expression
// We can translate the subquery to an IN expression
_filterWriter.WriteInFilter(itemExpression,
expression.QueryModel.MainFromClause.FromExpression);
return(expression);
}
}
}
else if (expression.QueryModel.MainFromClause.FromExpression.NodeType == ExpressionType.MemberAccess)
{
var itemExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
if (itemExpression is SelectVariableNameExpression)
{
_filterWriter.WriteInFilter(expression.QueryModel.MainFromClause.FromExpression,
contains.Item);
return(expression);
}
}
}
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is AllResultOperator)
{
var all = (AllResultOperator)expression.QueryModel.ResultOperators[0];
var existingWriter = _filterWriter;
_filterWriter = new FilterWriter(this, QueryBuilder, new StringBuilder()); // TODO: Could check FromExpression to see if it is optimisable
QueryBuilder.StartNotExists();
var mappedExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedExpression);
_filterWriter.WriteInvertedFilterPredicate(all.Predicate);
QueryBuilder.AddFilterExpression(_filterWriter.FilterExpression);
QueryBuilder.EndNotExists();
_filterWriter = existingWriter;
return(expression);
}
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is AnyResultOperator)
{
QueryBuilder.StartExists();
var outerFilterWriter = _filterWriter;
_filterWriter = new FilterWriter(this, QueryBuilder, new StringBuilder());
var itemVarName = SparqlQueryBuilder.SafeSparqlVarName(expression.QueryModel.MainFromClause.ItemName);
var mappedFromExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedFromExpression);
if (mappedFromExpression is SelectVariableNameExpression)
{
QueryBuilder.RenameVariable((mappedFromExpression as SelectVariableNameExpression).Name,
itemVarName);
}
foreach (var bodyClause in expression.QueryModel.BodyClauses)
{
if (bodyClause is WhereClause)
{
var whereClause = bodyClause as WhereClause;
VisitExpression(whereClause.Predicate);
}
else
{
CreateUnhandledItemException(bodyClause, "VisitSubQueryExpression");
}
}
var innerFilter = _filterWriter.ToString();
if (!string.IsNullOrEmpty(innerFilter))
{
QueryBuilder.AddFilterExpression(innerFilter);
}
_filterWriter = outerFilterWriter;
QueryBuilder.EndExists();
return(expression);
}
else if (expression.QueryModel.ResultOperators.Count == 0)
{
var itemVarName = SparqlQueryBuilder.SafeSparqlVarName(expression.QueryModel.MainFromClause.ItemName);
var mappedFromExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedFromExpression);
if (mappedFromExpression is SelectVariableNameExpression)
{
// Rename the variable in the SPARQL so that it matches the LINQ variable
QueryBuilder.RenameVariable((mappedFromExpression as SelectVariableNameExpression).Name, itemVarName);
(mappedFromExpression as SelectVariableNameExpression).Name = itemVarName;
}
foreach (var bodyClause in expression.QueryModel.BodyClauses)
{
if (bodyClause is WhereClause)
{
var whereClause = bodyClause as WhereClause;
VisitExpression(whereClause.Predicate);
}
else
{
CreateUnhandledItemException(bodyClause, "VisitSubQueryExpression");
}
}
return(mappedFromExpression);
}
return(base.VisitSubQueryExpression(expression));
}
public SparqlGeneratorWhereExpressionOptimisationVisitor(SparqlQueryBuilder queryBuilder)
{
_queryBuilder = queryBuilder;
}
protected override Expression VisitSubQueryExpression(SubQueryExpression expression)
{
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is ContainsResultOperator)
{
var contains = expression.QueryModel.ResultOperators[0] as ContainsResultOperator;
if (expression.QueryModel.MainFromClause.FromExpression.NodeType == ExpressionType.Constant &&
contains.Item is MemberExpression)
{
var itemExpression = VisitExpression(contains.Item);
if (itemExpression is SelectVariableNameExpression)
{
// We can translate the subquery to an IN expression
_filterWriter.WriteInFilter(contains.Item, expression.QueryModel.MainFromClause.FromExpression);
return(expression);
}
}
else if (expression.QueryModel.MainFromClause.FromExpression.NodeType == ExpressionType.MemberAccess)
{
var itemExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
if (itemExpression is SelectVariableNameExpression)
{
_filterWriter.WriteInFilter(expression.QueryModel.MainFromClause.FromExpression,
contains.Item);
return(expression);
}
}
}
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is AllResultOperator)
{
var all = expression.QueryModel.ResultOperators[0] as AllResultOperator;
if (all != null)
{
FilterWriter existingWriter = _filterWriter;
_filterWriter = new FilterWriter(this, this.QueryBuilder, new StringBuilder());
QueryBuilder.StartNotExists();
var mappedExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedExpression);
_filterWriter.WriteInvertedFilterPredicate(all.Predicate);
QueryBuilder.AddFilterExpression(_filterWriter.FilterExpression);
QueryBuilder.EndNotExists();
_filterWriter = existingWriter;
return(expression);
}
}
if (expression.QueryModel.ResultOperators.Count == 1 &&
expression.QueryModel.ResultOperators[0] is AnyResultOperator)
{
QueryBuilder.StartExists();
var outerFilterWriter = _filterWriter;
_filterWriter = new FilterWriter(this, QueryBuilder, new StringBuilder());
var itemVarName = SparqlQueryBuilder.SafeSparqlVarName(expression.QueryModel.MainFromClause.ItemName);
var mappedFromExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedFromExpression);
if (mappedFromExpression is SelectVariableNameExpression)
{
QueryBuilder.RenameVariable((mappedFromExpression as SelectVariableNameExpression).Name,
itemVarName);
}
foreach (var bodyClause in expression.QueryModel.BodyClauses)
{
if (bodyClause is WhereClause)
{
var whereClause = bodyClause as WhereClause;
VisitExpression(whereClause.Predicate);
}
else
{
CreateUnhandledItemException(bodyClause, "VisitSubQueryExpression");
}
}
var innerFilter = _filterWriter.ToString();
if (!String.IsNullOrEmpty(innerFilter))
{
QueryBuilder.AddFilterExpression(innerFilter);
}
_filterWriter = outerFilterWriter;
QueryBuilder.EndExists();
return(expression);
}
else if (expression.QueryModel.ResultOperators.Count == 0)
{
var itemVarName = SparqlQueryBuilder.SafeSparqlVarName(expression.QueryModel.MainFromClause.ItemName);
var mappedFromExpression = VisitExpression(expression.QueryModel.MainFromClause.FromExpression);
QueryBuilder.AddQuerySourceMapping(expression.QueryModel.MainFromClause, mappedFromExpression);
if (mappedFromExpression is SelectVariableNameExpression)
{
// Rename the variable in the SPARQL so that it matches the LINQ variable
QueryBuilder.RenameVariable((mappedFromExpression as SelectVariableNameExpression).Name, itemVarName);
(mappedFromExpression as SelectVariableNameExpression).Name = itemVarName;
}
foreach (var bodyClause in expression.QueryModel.BodyClauses)
{
if (bodyClause is WhereClause)
{
var whereClause = bodyClause as WhereClause;
VisitExpression(whereClause.Predicate);
}
else
{
CreateUnhandledItemException(bodyClause, "VisitSubQueryExpression");
}
}
return(mappedFromExpression);
}
return(base.VisitSubQueryExpression(expression));
}
SparqlGeneratorQueryModelVisitor(EntityContext context)
{
_context = context;
_queryBuilder = new SparqlQueryBuilder(context);
}
public FilterWriter(SparqlGeneratorWhereExpressionTreeVisitor parentVisitor, SparqlQueryBuilder queryBuilder,
StringBuilder filterExpressionBuilder) : base(queryBuilder)
{
_parent = parentVisitor;
_filterExpressionBuilder = filterExpressionBuilder;
}
