private bool HandleEqualsNotEquals(BinaryExpression equalityExpression)
{
ConstantExpression constantExpression = ExtractConstantExpression(equalityExpression);
if (constantExpression == null)
{
return(false);
}
Expression variableExpression = equalityExpression.Left.Equals(constantExpression)
? equalityExpression.Right
: equalityExpression.Left;
var variablePropertyHint = GetPropertyHint(variableExpression);
var variableIsAddress = variablePropertyHint != null &&
(variablePropertyHint.MappingType == PropertyMappingType.Address ||
variablePropertyHint.MappingType == PropertyMappingType.Id);
var value = constantExpression.Value;
var defValue = variableExpression.Type.GetDefaultValue();
if ((value == null && defValue == null) || (value != null && value.Equals(defValue)))
{
if (variableIsAddress)
{
var querySourceReferenceExpression =
((MemberExpression)variableExpression).Expression as QuerySourceReferenceExpression;
var varname = querySourceReferenceExpression.ReferencedQuerySource.ItemName;
var filter = equalityExpression.NodeType == ExpressionType.NotEqual
? "( bound(?{0}))"
: "(!bound(?{0}))";
_filterWriter.AppendFormat(filter, varname);
return(true);
}
else
{
string varname = null;
QueryBuilder.StartOptional();
var convertedExpression = VisitExpression(variableExpression);
QueryBuilder.EndOptional();
if (convertedExpression is SelectVariableNameExpression)
{
varname = (convertedExpression as SelectVariableNameExpression).Name;
}
if (varname != null)
{
string filter;
if (variableExpression.Type.IsValueType && defValue != null)
{
filter = equalityExpression.NodeType == ExpressionType.NotEqual
? "(bound(?{0}) && (?{0} != {1}))"
: "(!bound(?{0}) || (?{0} = {1}))";
}
else
{
filter = equalityExpression.NodeType == ExpressionType.NotEqual
? "( bound(?{0}))"
: "(!bound(?{0}))";
}
if (defValue != null)
{
_filterWriter.AppendFormat(filter, varname,
_filterWriter.MakeSparqlConstant(defValue));
}
else
{
_filterWriter.AppendFormat(filter, varname);
}
return(true);
}
}
}
if (variableIsAddress && value != null)
{
var querySourceReferenceExpression = ((MemberExpression)variableExpression).Expression as QuerySourceReferenceExpression;
var varname = querySourceReferenceExpression.ReferencedQuerySource.ItemName;
var filter = equalityExpression.NodeType == ExpressionType.Equal
? "( sameTerm(?{0}, <{1}>))"
: "(!sameTerm(?{0}, <{1}>))";
_filterWriter.AppendFormat(filter, varname, MakeResourceAddress(GetPropertyInfo(constantExpression), value.ToString()));
return(true);
}
return(false);
}
