/// <summary>
/// Method that will actually resolve the instances.
/// </summary>
/// <typeparam name="TInstance">The type of the instances we want.</typeparam>
/// <returns>
/// Returns a list with <see cref="TInstance"/> instances.
/// The list could be empty when no implementations were found.
/// </returns>
public List <TInstance> ResolveInstances <TInstance>(bool onlyLookInPlugins = true)
{
// get the type once, instead of once every type.
IsOfType typeCheckMethod = IsSubclassOf;
var typeOfTInstance = typeof(TInstance);
if (typeOfTInstance.IsInterface)
{
typeCheckMethod = ImplementsInterface;
}
var returnList = new List <TInstance>();
var assemblies = getAssemblyCollection(onlyLookInPlugins);
if (assemblies.Count == 0)
{
LogUtility.Out("[SK] InstanceResolver: No assemblies found.");
return(returnList);
}
foreach (var assembly in assemblies)
{
LogUtility.Out("[SK] InstanceResolver: Scanning assembly " + assembly.Location);
// loop all assemblies, see if it contains types we are looking for.
Type[] typesInAssembly = new Type[0];
try
{
typesInAssembly = assembly.GetTypes();
}
catch (Exception exception)
{
// Not yet able to cover this piece of code with a unit test.
var survivalKitException = new SurvivalKit.Exceptions.SurvivalKitPluginException("SK.ResolveInstances", "SurvivalKit.Utility.InstanceResolver", "Unable to extract types from assembly: " + assembly.FullName, exception);
LogUtility.Exception(survivalKitException);
}
foreach (var typeInAssembly in typesInAssembly)
{
if (typeInAssembly.IsInterface || typeInAssembly.IsAbstract)
{
continue;
}
// loop all types in the assembly. only act when it matches our needs.
if (typeCheckMethod(typeInAssembly, typeOfTInstance))
{
var constructors = typeInAssembly.GetConstructors();
var foundValidConstructor = false;
foreach (var item in constructors)
{
if (item.GetParameters().Length == 0)
{
foundValidConstructor = true;
}
}
if (!foundValidConstructor)
{
// there is no constructor without arguments, we can't instantiate those (yet?)
continue;
}
try
{
var instance = (TInstance)Activator.CreateInstance(typeInAssembly);
returnList.Add(instance);
}
catch (Exception exception)
{
var wrappedException = new SurvivalKitPluginException("ResolvePlugin", "SurvivalKit.InstanceResolver.ResolveInstances", "Error while invoking constructor", exception);
LogUtility.Exception(wrappedException);
}
}
}
}
return(returnList);
}
