/// <summary>
/// TestMethodory method for returning a request processor
/// </summary>
/// <typeparam name="T">type of request</typeparam>
/// <returns>request processor matching type parameter</returns>
internal IRequestProcessor <T> CreateRequestProcessor <T>(Expression expression)
where T : class
{
_ = expression ?? throw new ArgumentNullException(nameof(expression), "Expression passed to CreateRequestProcessor must not be null.");
Type?genericType = new MethodCallExpressionTypeFinder().GetGenericType(expression);
_ = genericType ?? throw new ArgumentNullException(nameof(expression), "Generic type of Expression passed to CreateRequestProcessor must not be null.");
return(CreateRequestProcessor <T>(genericType.Name));
}
internal IRequestProcessor <T> CreateRequestProcessor <T>(Expression expression)
where T : class
{
if (expression == null)
{
throw new ArgumentNullException(
nameof(expression),
"Expression passed to CreateRequestProcessor must not be null.");
}
string requestType = new MethodCallExpressionTypeFinder().GetGenericType(expression).Name;
return(CreateRequestProcessor <T>(requestType));
}
/// <summary>
/// TestMethodory method for returning a request processor
/// </summary>
/// <typeparam name="T">type of request</typeparam>
/// <returns>request processor matching type parameter</returns>
internal IRequestProcessor <T> CreateRequestProcessor <T>(Expression expression)
where T : class
{
if (expression == null)
{
const string NullExpressionMessage = "Expression passed to CreateRequestProcessor must not be null.";
throw new ArgumentNullException("Expression", NullExpressionMessage);
}
string requestType = new MethodCallExpressionTypeFinder().GetGenericType(expression).Name;
IRequestProcessor <T> req = CreateRequestProcessor <T>(requestType);
return(req);
}
/// <summary>
/// generic execute, delegates execution to TwitterContext
/// </summary>
/// <typeparam name="TResult">type of query</typeparam>
/// <param name="expression">Expression tree</param>
/// <returns>list of results from query</returns>
public TResult Execute <TResult>(Expression expression)
{
bool isEnumerable =
typeof(TResult).Name == "IEnumerable`1" ||
typeof(TResult).Name == "IEnumerable";
// generic parameter type for method call
Type resultType = new MethodCallExpressionTypeFinder().GetGenericType(expression);
Type[] genericArguments = new Type[] { resultType };
// generic method instance via reflection
var methodInfo = Context.GetType().GetMethod("Execute", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
MethodInfo genericMethodInfo = methodInfo.MakeGenericMethod(genericArguments);
// use reflection to execute the generic method with the proper arguments
// Note: look at ProcessResults method in PostProcessor and you'll see what is being executed
return((TResult)genericMethodInfo.Invoke(Context, new object[] { expression, isEnumerable }));
}
