Question

first:

public static String ConvertServerToClientAdapter(String adapterServer)
    {
        string temp = adapterServer.Substring(0, adapterServer.IndexOf("/"));
        switch (temp)
        {
            case "f":
                {
                    return "FA";
                }
            case "g":
                {
                    return "Gi";
                }
            case "s":
                {
                    return "SE";
                }
            case "a":
                {
                    return "ATM";
                }
            default:
                return null;
        }
    }

second:

public static String ConvertClientToServerAdapter(String adapterClient)
{
    switch (adapterClient)
    {
        case "FA":
            {
                return "f";
            }
        case "Gi":
            {
                return "g";
            }
        case "SE":
            {
                return "s";
            }
        case "ATM":
            {
                return "a";
            }
        default:
            return null;
    }
}

Answer 1

You can store the string pairs in a dictionary. That will reduce the duplication of having two places in the code saying that ‘a’ is paired with ‘ATM’.

For the forward conversion, just index the dictionary. return _dict[adapterServer];.

Edit: maybe it should be TryGetValue if you want to return null for invalid input, rather than throwing exceptions.

For backward, use linq:

 return _dict.Elements.FirstOrDefault(e => e.Value == adapterClient).Key);

You can swap what is forward/backward depending on what is used more often, forward dictionary indexing is faster than linq.