/// <summary>
/// Converts a Path into its Algebra Form.
/// </summary>
/// <param name="context">Path Transformation Context.</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
bool top = context.Top;
// The Object becomes a temporary variable then we transform the LHS of the path
context.Object = context.GetNextTemporaryVariable();
context.Top = false;
context.AddTriplePattern(context.GetTriplePattern(context.Subject, _lhs, context.Object));
// The Subject is then the Object that results from the LHS transform since the
// Transform may adjust the Object
context.Subject = context.Object;
// We then reset the Object to be the target Object so that if the RHS is the last part
// of the Path then it will complete the path transformation
// If it isn't the last part of the path it will be set to a new temporary variable
context.Top = top;
if (context.Top)
{
context.ResetObject();
}
else
{
context.Object = context.GetNextTemporaryVariable();
}
context.Top = top;
context.AddTriplePattern(context.GetTriplePattern(context.Subject, _rhs, context.Object));
return(context.ToAlgebra());
}
/// <summary>
/// Converts a Path into its Algebra Form
/// </summary>
/// <param name="context">Path Transformation Context</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
if (this._n > 0)
{
// Generate a Triple Pattern for each step in the cardinality
for (int i = 0; i < this._n; i++)
{
context.Object = context.GetNextTemporaryVariable();
if (i < this._n - 1 || !context.Top)
{
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._path, context.Object));
context.Subject = context.Object;
}
else
{
context.ResetObject();
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._path, context.Object));
}
}
return(context.ToAlgebra());
}
else
{
return(new ZeroLengthPath(context.Subject, context.Object, this._path));
}
}
/// <summary>
/// Converts a Path into its Algebra Form
/// </summary>
/// <param name="context">Path Transformation Context</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
bool top = context.Top;
//The Object becomes a temporary variable then we transform the LHS of the path
context.Object = context.GetNextTemporaryVariable();
context.Top = false;
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._lhs, context.Object));
//The Subject is then the Object that results from the LHS transform since the
//Transform may adjust the Object
context.Subject = context.Object;
//We then reset the Object to be the target Object so that if the RHS is the last part
//of the Path then it will complete the path transformation
//If it isn't the last part of the path it will be set to a new temporary variable
context.Top = top;
if (context.Top)
{
context.ResetObject();
}
else
{
context.Object = context.GetNextTemporaryVariable();
}
context.Top = top;
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._rhs, context.Object));
return context.ToAlgebra();
}
/// <summary>
/// Converts a Path into its Algebra Form
/// </summary>
/// <param name="context">Path Transformation Context</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
PatternItem tempVar = context.GetNextTemporaryVariable();
context.AddTriplePattern(new PropertyPathPattern(context.Subject, new FixedCardinality(this._path, this._n), tempVar));
context.AddTriplePattern(new PropertyPathPattern(tempVar, new ZeroOrMore(this._path), context.Object));
return(context.ToAlgebra());
}
/// <summary>
/// Converts a Path into its Algebra Form
/// </summary>
/// <param name="context">Path Transformation Context</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
PatternItem tempVar = context.GetNextTemporaryVariable();
context.AddTriplePattern(new PropertyPathPattern(context.Subject, new FixedCardinality(this._path, this._n), tempVar));
context.AddTriplePattern(new PropertyPathPattern(tempVar, new ZeroOrMore(this._path), context.Object));
return context.ToAlgebra();
}
/// <summary>
/// Converts a Path into its Algebra Form
/// </summary>
/// <param name="context">Path Transformation Context</param>
/// <returns></returns>
public override ISparqlAlgebra ToAlgebra(PathTransformContext context)
{
if (this._n > 0)
{
//Generate a Triple Pattern for each step in the cardinality
for (int i = 0; i < this._n; i++)
{
context.Object = context.GetNextTemporaryVariable();
if (i < this._n - 1 || !context.Top)
{
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._path, context.Object));
context.Subject = context.Object;
}
else
{
context.ResetObject();
context.AddTriplePattern(context.GetTriplePattern(context.Subject, this._path, context.Object));
}
}
return context.ToAlgebra();
}
else
{
return new ZeroLengthPath(context.Subject, context.Object, this._path);
}
}