/// <summary>
/// create like expression
/// </summary>
/// <returns></returns>
private static Expression <Func <T, bool> > GetLkExpression <T>(ParameterExpression parameter,
RSqlQueryParser.ComparisonContext context,
JsonNamingPolicy jsonNamingPolicy = null)
{
var expressionValue = GetSelector <T>(parameter, context, jsonNamingPolicy);
var values = RSqlQueryGetValueHelper.GetValues(expressionValue.Property.PropertyType, context.arguments());
if (values.Count > 1)
{
throw new ComparisonTooManyArgumentException(context);
}
var criteria = Convert.ToString(values[0]) ?? string.Empty;
var maskStar = "{" + Guid.NewGuid() + "}";
criteria = criteria.Replace(@"\*", maskStar);
MethodInfo method;
if (!criteria.Contains('*'))
{
criteria += '*';
}
if (criteria.StartsWith("*", StringComparison.Ordinal) && criteria.EndsWith("*", StringComparison.Ordinal))
{
method = QueryReflectionHelper.MethodStringContains;
}
else if (criteria.StartsWith("*", StringComparison.Ordinal))
{
method = QueryReflectionHelper.MethodStringEndsWith;
}
else
{
method = QueryReflectionHelper.MethodStringStartsWith;
}
criteria = criteria.Replace("*", "").Replace(maskStar, "*");
return(Expression.Lambda <Func <T, bool> >(Expression.Call(expressionValue.Expression,
method,
Expression.Constant(criteria, expressionValue.Property.PropertyType)), parameter));
}
/// <summary>
/// create is null expression ( operator "=is-null=" or "=nil=" )
/// </summary>
/// <param name="parameter"></param>
/// <param name="context"></param>
/// <param name="jsonNamingPolicy"></param>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static Expression <Func <T, bool> > GetIsNullExpression <T>(ParameterExpression parameter,
RSqlQueryParser.ComparisonContext context,
JsonNamingPolicy jsonNamingPolicy = null)
{
var expressionValue = GetSelector <T>(parameter, context, jsonNamingPolicy);
if (!RSqlQueryGetValueHelper.IsNullableComparisonType(expressionValue.Property.PropertyType))
{
throw new ComparisonInvalidComparatorSelectionException(context);
}
var values = RSqlQueryGetValueHelper.GetValues(typeof(bool), context.arguments());
if (!values.Any())
{
throw new ComparisonNotEnoughArgumentException(context);
}
if (values.Count > 1)
{
throw new ComparisonTooManyArgumentException(context);
}
var result = Expression.Lambda <Func <T, bool> >(Expression.Equal(
expressionValue.Expression,
Expression.Constant(null, typeof(object))), parameter);
if ((bool)values[0])
{
return(result);
}
var body = Expression.Not(result.Body);
result = Expression.Lambda <Func <T, bool> >(body, parameter);
return(result);
}
/// <summary>
/// extract the multi value
/// </summary>
/// <param name="expressionValue"></param>
/// <param name="context"></param>
/// <returns></returns>
/// <exception cref="ComparisonNotEnoughArgumentException"></exception>
private static List <object> GetMultipleValue(ExpressionValue expressionValue,
RSqlQueryParser.ComparisonContext context)
{
return(RSqlQueryGetValueHelper.GetValues(expressionValue.Property.PropertyType, context.arguments()));
}