CachedMethods.cs

bool TryGetTasksFromCache(int userId = -1, string stage, out List<UserTask> cachedTasks)
{
    cachedTasks = DataCache[GetCacheKey(userId, stage)] as List<UserTask>;
    return (cachedTasks != null);
}

List<UserTask> GetTasks(int userId = -1, string stage, List<Severity> severities = null)
{
    List<UserTask> listOfUserTasks;
    if (TryGetTasksFromCache(userId, stage, out listOfUserTasks))
        return listOfUserTasks;
    
    listOfUserTasks = GetTasksNotFromCache(userId, stage, severities);
    SetDataCache(userId, stage, listOfUserTasks);
    return listOfUserTasks;
}

void ClearDataCache(int userId, string stage)
{
    DataCache.Remove(GetCacheKey(userId, stage));
}

void SetDataCache(int userId, string stage, List<UserTask> tasks)
{
    // cache policy
    var policy = new CacheItemPolicy
    {
        AbsoluteExpiration = DateTimeOffset.UtcNow.AddSeconds(DATA_CACHE_NUMBER_OF_SECONDS)
    };

    // storing data in cache.
    DataCache.Set(GetCacheKey(userId, stage), tasks, policy);
}

string GetCacheKey(int userId, string stage)
{
    return "listOfBaseTasks" + userId + stage;
}