/// <exception cref="NotSupportedException" />
/// <exception cref="InvalidOperationException" />
private IEnumerable <T> FilterComparsion(
Expression memberExpression, Expression keyExpression, ExpressionType type)
{
IComparsionIndex <T> index = FindComparsionIndex(memberExpression);
object key = keyExpression.GetValue();
switch (type)
{
case ExpressionType.GreaterThan:
return(index.GreaterThan(key, exclusive: true));
case ExpressionType.GreaterThanOrEqual:
return(index.GreaterThan(key, exclusive: false));
case ExpressionType.LessThan:
return(index.LessThan(key, exclusive: true));
case ExpressionType.LessThanOrEqual:
return(index.LessThan(key, exclusive: false));
default:
throw new NotSupportedException($"Expression {type} should be Comparsion");
}
}
/// <exception cref="NotSupportedException" />
/// <exception cref="InvalidOperationException" />
private IEnumerable <T> FilterStringStartsWith(MethodCallExpression methodCall)
{
if (methodCall.Method.DeclaringType == typeof(String) &&
methodCall.Method.Name == nameof(String.StartsWith))
{
IComparsionIndex <T> index = FindComparsionIndex(methodCall.Object);
string keyFrom = (string)methodCall.Arguments.First().GetValue();
if (String.IsNullOrEmpty(keyFrom))
{
return(index.GreaterThan(keyFrom, false));
}
char lastChar = keyFrom[keyFrom.Length - 1];
string keyTo = keyFrom.Substring(0, keyFrom.Length - 1) + (char)(lastChar + 1);
return(index.Between(keyFrom, false, keyTo, true));
}
throw new NotSupportedException(
$"Predicate body {methodCall} should be String.StartsWith()");
}