Design Pattern - Creational - Factory

 

Scenario:

Create a Redis Cache factory.

Solution:

Creational Pattern for the creation of objects. So the Factory creates the objects required so its delegating the "new" to factory from the caller.

Example: Redis Cache factory which creates the objects of RedisCacheClient based on configurations

1. RedisCacheFactory and the RedisCache



 
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namespace TestProject
{
    public interface IRedisCache
    {
        void Push(Dictionary<string, string> data);
    }

    public class RedisCache : IRedisCache
    {
        public void Push(Dictionary<string, string> data)
        {
            // Push to Redis
        }
    }

    public class RedisCacheFactory
    {
        private static readonly Dictionary<Tuple<Type, string>, IRedisCache?> _clientCache;
        public RedisCacheFactory()
        {

        }
        public static IRedisCache? GetCacheClient(Type dataType, string serviceName)
        {
            return InternalGetCacheClient(dataType, serviceName);
        }

        private static IRedisCache? InternalGetCacheClient(Type dataType, string serviceName)
        {
            var cacheKey = new Tuple<Type, string>(dataType, serviceName);

            if (_clientCache.TryGetValue(cacheKey, out var client))
            {
                return client;
            }

            var type = (typeof(RedisCache)).MakeGenericType(dataType);
            client =
                (IRedisCache)
                Activator.CreateInstance(type, serviceName)!;

            _clientCache[cacheKey] = client;

            return client;
        }
    }
}



2. Push the Log to Redis through the client created & returned by the factory



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namespace TestProject { public class Caller { public void PushData(Dictionary<string, string> data) { var type = Type.GetType("TestProject.ApiLog"); var redisClient = RedisCacheFactory.GetCacheClient(type, "api"); var dictionary = new Dictionary<string, string>(); dictionary.Add("logapi", "{Request}"); redisClient.Push(dictionary); } } }