/// <summary>
/// Calculator operator and get the result TwoFactorExpression.
/// </summary>
private void CalculateOprator()
{
var op = this.operatorStack.Pop();
if (op.Text != "(")
{
try
{
var right = this.dataStack.Pop();
var left = this.dataStack.Pop();
TwoFactorExpression exp = new TwoFactorExpression()
{
RightExpression = right,
LeftExpression = left,
OperatorToken = op
};
this.dataStack.Push(exp);
}
catch
{
throw new ArgumentException($"Wrong Expression Passed Near {op.Text}");
}
}
}
private FilterModelCollection BuildFilterFromExpression(TwoFactorExpression expression)
{
if (expression == null)
{
return(null);
}
Debug.WriteLine(expression.ToString());
FilterModelCollection collection = new FilterModelCollection();
if (expression.OperatorToken.Text == "and")
{
collection.Operator = LogicOperator.And;
if (expression.LeftExpression != null)
{
var child = this.BuildFilterFromExpression(expression.LeftExpression);
collection.Filters.Add(child);
}
if (expression.RightExpression != null)
{
var child = this.BuildFilterFromExpression(expression.RightExpression);
collection.Filters.Add(child);
}
}
else if (expression.OperatorToken.Text == "or")
{
collection.Operator = LogicOperator.Or;
if (expression.LeftExpression != null)
{
var child = this.BuildFilterFromExpression(expression.LeftExpression);
collection.Filters.Add(child);
}
if (expression.RightExpression != null)
{
var child = this.BuildFilterFromExpression(expression.RightExpression);
collection.Filters.Add(child);
}
}
else
{
if (expression.LeftExpression.LeftExpression != null ||
expression.LeftExpression.RightExpression != null ||
expression.RightExpression.LeftExpression != null ||
expression.RightExpression.RightExpression != null)
{
throw new ArgumentException(
"Non logic expression should not have sub expression",
nameof(expression));
}
FilterModel model = new FilterModel();
model.Name = expression.LeftExpression.ValueToken.Text;
model.Value = expression.RightExpression.ValueToken.Text;
model.Operator = expression.OperatorToken.Text;
collection.Filters.Add(model);
}
return(collection);
}
/// <summary>
/// Parse the filter string in to filter model collection.
/// </summary>
/// <param name="filterStr">The filter string to be parsed.</param>
/// <returns>The filter Model collection.</returns>
public FilterModelCollection ParseFilter(string filterStr)
{
this.reader = new TokenReader(filterStr);
Token token;
do
{
token = this.reader.ReadNextToken();
if (token != null)
{
if (token.Type == TokenType.Operator)
{
if (token.Text == ")")
{
this.expectedBracket--;
}
if (this.operatorStack.Count > 0)
{
Token lastToken = this.operatorStack.Peek();
if (this.HighPriorityToken(lastToken, token))
{
this.PushOperator(token);
}
else
{
while (!this.HighPriorityToken(lastToken, token) && this.operatorStack.Count != 0)
{
this.CalculateOprator();
if (this.operatorStack.Count > 0)
{
lastToken = this.operatorStack.Peek();
}
}
if (token.Text != ")")
{
this.PushOperator(token);
}
else
{
var matchToken = this.operatorStack.Peek();
if (matchToken.Text != "(")
{
throw new ArgumentException("Unmatched bracket");
}
else
{
this.operatorStack.Pop();
}
}
}
}
else
{
if (token.Text != ")")
{
this.PushOperator(token);
}
else
{
throw new ArgumentException("Unmatched bracket");
}
}
}
else
{
TwoFactorExpression exp = new TwoFactorExpression {
ValueToken = token
};
this.dataStack.Push(exp);
}
}
}while (token != null);
while (this.operatorStack.Count > 0)
{
this.CalculateOprator();
}
if (this.expectedBracket != 0)
{
throw new ArgumentException("unmatched bracket");
}
if (this.dataStack.Count > 1)
{
throw new ArgumentException("The parse parse a wrong result based on given filter");
}
else
{
return(this.BuildFilterFromExpression(this.dataStack.Pop()));
}
}