工厂模式-带有可选参数

Question

I have a factory:

  public static class AdapterFactory
  {

    public static IAdapter GetAdapter(AdapterType claimType, int mid, int tid, int siteId, string version)
    {
    }
}

My problem is that sometimes the mid, tid, siteId and version parameters are not needed to construct an "Adapter", they are specific to only some kinds of adapters.

What is the best approach when parameters are not always required like in this situation?

Thanks for your help.

Answer 1

Specalise and make more factories, for example:

public static class MidAdapterFactory
{
    public static IAdapter GetAdapter(AdapterType claimType, int mid)
    {
    }
}

public static class TidAdapterFactory
{
    public static IAdapter GetAdapter(AdapterType claimType, int tid)
    {
    }
}

Also consider the builder pattern.

Answer 2

Look at optional arguments . You can give parameters default values, then omit them if you don't need them

public static class AdapterFactory
{
    public static IAdapter GetAdapter(AdapterType claimType, 
                                      int mid = 0, 
                                      int tid = 0, 
                                      int siteID = 0, 
                                      string version = null)
    {
        // Create adapter here
    }
}

Can now be used as so:

var adapter1 = AdapterFactory.GetAdapter(AdapterType.Regular, 1000, 50, 10, "1.0.0.0");
var adapter2 = AdapterFactory.GetAdapter(AdapterType.Minimal);