/// <summary>
/// Main evaluation method which is divided in two phases: Argument processing and
/// Function evaluation.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The result of the evaluation in an EvaluationValue instance.</returns>
public virtual EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
// Validate the function exists
context.Trace("Calling function: {0}", _applyBase.FunctionId);
IFunction function = EvaluationEngine.GetFunction(_applyBase.FunctionId);
if (function == null)
{
context.Trace("ERR: function not found {0}", _applyBase.FunctionId);
context.ProcessingError = true;
return(EvaluationValue.Indeterminate);
}
// Process the arguments.
FunctionParameterCollection arguments = ProcessArguments(context, new ExpressionCollection((ExpressionReadWriteCollection)_applyBase.Arguments));
// Call the function with the arguments processed.
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction(context, function, arguments.ToArray());
return(returnValue);
}
/// <summary>
/// Evaluates the target items and return wether the target applies to the context or not.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetItem">The target item in the context document.</param>
/// <returns></returns>
public virtual TargetEvaluationValue Evaluate(EvaluationContext context, ctx.TargetItemBase targetItem)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
if (_targetItems.IsAny)
{
context.Trace("IsAny");
return(TargetEvaluationValue.Match);
}
_evaluationValue = TargetEvaluationValue.NoMatch;
//Match TargetItem
foreach (TargetItemBase polItem in _targetItems.ItemsList)
{
foreach (TargetMatchBase match in polItem.Match)
{
_evaluationValue = TargetEvaluationValue.NoMatch;
context.Trace("Using function: {0}", match.MatchId);
IFunction matchFunction = EvaluationEngine.GetFunction(match.MatchId);
if (matchFunction == null)
{
context.Trace("ERR: function not found {0}", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
else if (matchFunction.Returns == null)
{
// Validates the function return value
context.Trace("ERR: The function '{0}' does not defines it's return value", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
else if (matchFunction.Returns != DataTypeDescriptor.Boolean)
{
context.Trace("ERR: Function does not return Boolean a value");
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
else
{
Context.AttributeElement attribute = EvaluationEngine.Resolve(context, match, targetItem);
if (attribute != null)
{
context.Trace("Attribute found, evaluating match function");
try
{
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction(context, matchFunction, match.AttributeValue, attribute);
_evaluationValue = returnValue.BoolValue ? TargetEvaluationValue.Match : TargetEvaluationValue.NoMatch;
}
catch (EvaluationException e)
{
context.Trace("ERR: {0}", e.Message);
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Validate MustBePresent
if (match.AttributeReference.MustBePresent)
{
if (context.IsMissingAttribute)
{
context.Trace("Attribute not found and must be present");
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
if (context.ProcessingError)
{
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
// Do not iterate if the value was found
if (_evaluationValue != TargetEvaluationValue.Match)
{
break;
}
}
}
// Do not iterate if the value was found
if (_evaluationValue == TargetEvaluationValue.Match)
{
return(_evaluationValue);
}
}
return(_evaluationValue);
}