/// <summary>
/// Add keyword value matching to the query.
/// </summary>
/// <param name="fitsKeyword"></param>
/// <param name="value"></param>
/// <returns></returns>
public IFitsQueryExpression KeywordMatching <T>(string fitsKeyword, T value)
{
var valueType = typeof(T);
var headerType = typeof(FitsHeaderIndexedRow);
var headerKeywordProps = headerType.GetProperties().Where(p => p.HasAttribute <FitsFieldAttribute>());
var matchingProp = headerKeywordProps.FirstOrDefault(p =>
p.GetCustomAttribute <FitsFieldAttribute>().Name == fitsKeyword);
if (matchingProp == null)
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"this keyword doesn't exist in the indexed keywords");
}
if (matchingProp.PropertyType != valueType && matchingProp.PropertyType.ToNullableUnderlying() != valueType)
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"the given value is not of type '{matchingProp.PropertyType.Name}'");
}
// The expression works on FitsSearchResult, which combines all the related SQL tables.
// Construct the expression dynamically from the property name linked to the FITS header name.
var exprParamType = typeof(FitsSearchResult);
// ... == targetValue
var targetValue = Expression.Constant(value);
// ((FitsSearchResult)x) => ...
var parameter = Expression.Parameter(exprParamType, "x");
// ((FitsSearchResult)x) => x.HeaderData.property
Expression property = Expression.PropertyOrField(parameter, nameof(FitsSearchResult.HeaderData));
property = Expression.PropertyOrField(property, matchingProp.Name);
// Convert property from nullable to non-nullable type because expressions can't
// really handle nullables (value gets always converted to non-nullable, and comparison
// between nullables and non-nullables will throw).
var nonNullableType = valueType.ToNullableUnderlying();
property = Expression.Convert(property, nonNullableType);
// ((FitsSearchResult)x) => x.HeaderData.property == targetValue
var body = Expression.Equal(property, targetValue);
var lambda = Expression.Lambda <Func <FitsSearchResult, bool> >(body, parameter);
var expr = new FitsQueryExpression()
{
Expression = lambda
};
return(expr);
}
/// <summary>
/// Search for string inside a FITS keyword value.
/// Both the fitsKeyword and the searchString must be strings.
/// </summary>
/// <param name="fitsKeyword"></param>
/// <param name="searchString"></param>
/// <returns></returns>
public IFitsQueryExpression KeywordSearch(string fitsKeyword, string searchString)
{
var exprParamType = typeof(FitsSearchResult);
var headerType = typeof(FitsHeaderIndexedRow);
var headerKeywordProps = headerType.GetProperties().Where(p => p.HasAttribute <FitsFieldAttribute>());
var matchingProp = headerKeywordProps.FirstOrDefault(p =>
p.GetCustomAttribute <FitsFieldAttribute>().Name == fitsKeyword);
if (matchingProp == null)
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"this keyword doesn't exist in the indexed keywords");
}
if (matchingProp.PropertyType != typeof(string))
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"the given value is not of type '{matchingProp.PropertyType.Name}'");
}
var targetValue = Expression.Constant(searchString);
var parameter = Expression.Parameter(exprParamType, "x");
Expression property = Expression.PropertyOrField(parameter, nameof(FitsSearchResult.HeaderData));
property = Expression.PropertyOrField(property, matchingProp.Name);
MethodInfo method = typeof(string).GetMethod("Contains", new[] { typeof(string) });
var body = Expression.Call(property, method, targetValue);
var lambda = Expression.Lambda <Func <FitsSearchResult, bool> >(body, parameter);
var expr = new FitsQueryExpression()
{
Expression = lambda
};
return(expr);
}
/// <summary>
/// Does a comparison with the given operator to a numeric FITS keyword value.
/// </summary>
/// <param name="fitsKeyword"></param>
/// <param name="value"></param>
/// <param name="comparison"></param>
/// <returns></returns>
public IFitsQueryExpression NumericValueComparison(string fitsKeyword, double value,
NumericComparison comparison)
{
var exprParamType = typeof(FitsSearchResult);
var headerType = typeof(FitsHeaderIndexedRow);
var headerKeywordProps = headerType.GetProperties().Where(p => p.HasAttribute <FitsFieldAttribute>());
var matchingProp = headerKeywordProps.FirstOrDefault(p =>
p.GetCustomAttribute <FitsFieldAttribute>().Name == fitsKeyword);
if (matchingProp == null)
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"this keyword doesn't exist in the indexed keywords");
}
if (matchingProp.PropertyType != typeof(double))
{
throw new FitsDatabaseException($"Cannot add keyword matching for keyword '{fitsKeyword}' to the query, " +
$"the given value is not of type '{matchingProp.PropertyType.Name}'");
}
var targetValue = Expression.Constant(value);
var parameter = Expression.Parameter(exprParamType, "x");
Expression property = Expression.PropertyOrField(parameter, nameof(FitsSearchResult.HeaderData));
property = Expression.PropertyOrField(property, matchingProp.Name);
Expression body = null;
switch (comparison)
{
case NumericComparison.Eq:
body = Expression.Equal(property, targetValue);
break;
case NumericComparison.Gt:
body = Expression.GreaterThan(property, targetValue);
break;
case NumericComparison.Gte:
body = Expression.GreaterThanOrEqual(property, targetValue);
break;
case NumericComparison.Lt:
body = Expression.LessThan(property, targetValue);
break;
case NumericComparison.Lte:
body = Expression.LessThanOrEqual(property, targetValue);
break;
}
var lambda = Expression.Lambda <Func <FitsSearchResult, bool> >(body, parameter);
var expr = new FitsQueryExpression()
{
Expression = lambda
};
return(expr);
}
