예제 #1
0
        /// <summary>
        /// Gets the value of the expression as evaluated in a given Context for a given Binding.
        /// </summary>
        /// <param name="context">Evaluation Context.</param>
        /// <param name="bindingID">Binding ID.</param>
        /// <returns></returns>
        public override IValuedNode Evaluate(SparqlEvaluationContext context, int bindingID)
        {
            _funcContext = context[SparqlSpecsHelper.SparqlKeywordBNode] as BNodeFunctionContext;

            if (_funcContext == null)
            {
                _funcContext = new BNodeFunctionContext(context.InputMultiset.GetHashCode());
                context[SparqlSpecsHelper.SparqlKeywordBNode] = _funcContext;
            }
            else if (_funcContext.CurrentInput != context.InputMultiset.GetHashCode())
            {
                // Clear the Context
                _funcContext.BlankNodes.Clear();
                context[SparqlSpecsHelper.SparqlKeywordBNode] = _funcContext;
            }

            if (_expr == null)
            {
                // If no argument then always a fresh BNode
                return(_funcContext.Graph.CreateBlankNode().AsValuedNode());
            }
            else
            {
                INode temp = _expr.Evaluate(context, bindingID);
                if (temp != null)
                {
                    if (temp.NodeType == NodeType.Literal)
                    {
                        ILiteralNode lit = (ILiteralNode)temp;

                        if (lit.DataType == null)
                        {
                            if (lit.Language.Equals(string.Empty))
                            {
                                if (!_funcContext.BlankNodes.ContainsKey(bindingID))
                                {
                                    _funcContext.BlankNodes.Add(bindingID, new Dictionary <string, INode>());
                                }

                                if (!_funcContext.BlankNodes[bindingID].ContainsKey(lit.Value))
                                {
                                    _funcContext.BlankNodes[bindingID].Add(lit.Value, _funcContext.Graph.CreateBlankNode());
                                }
                                return(_funcContext.BlankNodes[bindingID][lit.Value].AsValuedNode());
                            }
                            else
                            {
                                throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to a lanuage specified literal");
                            }
                        }
                        else
                        {
                            throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to a typed literal node");
                        }
                    }
                    else
                    {
                        throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to a non-literal node");
                    }
                }
                else
                {
                    throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to null");
                }
            }
        }
예제 #2
0
        /// <summary>
        /// Gets the value of the expression as evaluated in a given Context for a given Binding
        /// </summary>
        /// <param name="context">Evaluation Context</param>
        /// <param name="bindingID">Binding ID</param>
        /// <returns></returns>
        public override IValuedNode Evaluate(SparqlEvaluationContext context, int bindingID)
        {
            this._funcContext = context[SparqlSpecsHelper.SparqlKeywordBNode] as BNodeFunctionContext;

            if (this._funcContext == null)
            {
                this._funcContext = new BNodeFunctionContext(context.InputMultiset.GetHashCode());
                context[SparqlSpecsHelper.SparqlKeywordBNode] = this._funcContext;
            }
            else if (this._funcContext.CurrentInput != context.InputMultiset.GetHashCode())
            {
                this._funcContext = new BNodeFunctionContext(context.InputMultiset.GetHashCode());
                context[SparqlSpecsHelper.SparqlKeywordBNode] = this._funcContext;
            }

            if (this._expr == null)
            {
                //If no argument then always a fresh BNode
                return new BlankNode(this._funcContext.Graph, this._funcContext.Mapper.GetNextID());
            }
            else
            {
                INode temp = this._expr.Evaluate(context, bindingID);
                if (temp != null)
                {
                    if (temp.NodeType == NodeType.Literal)
                    {
                        ILiteralNode lit = (ILiteralNode)temp;

                        if (lit.DataType == null)
                        {
                            if (lit.Language.Equals(string.Empty))
                            {
                                if (!this._funcContext.BlankNodes.ContainsKey(bindingID))
                                {
                                    this._funcContext.BlankNodes.Add(bindingID, new Dictionary<string, INode>());
                                }

                                if (!this._funcContext.BlankNodes[bindingID].ContainsKey(lit.Value))
                                {
                                    this._funcContext.BlankNodes[bindingID].Add(lit.Value, new BlankNode(this._funcContext.Graph, this._funcContext.Mapper.GetNextID()));
                                }
                                return this._funcContext.BlankNodes[bindingID][lit.Value].AsValuedNode();
                            }
                            else
                            {
                                throw new RdfQueryException("Cannot create a Blank Node whne the argument Expression evaluates to a lanuage specified literal");
                            }
                        }
                        else
                        {
                            throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to a typed literal node");
                        }
                    }
                    else
                    {
                        throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to a non-literal node");
                    }
                }
                else
                {
                    throw new RdfQueryException("Cannot create a Blank Node when the argument Expression evaluates to null");
                }
            }
        }