Intermezzo–options for loading multiple providers of data – part 10
We have 2 national banks – and we gather exchange rates from there. What if we want to add more banks -or let other programmers to add their dll’s to our software to just display the exchange rates from other banks ?
Option 1: HardCode all the list
1 2 3 4 5 6 | var l = new List<IExchangeRates[]>{new GetFirstBank()),new GetSecondBank()),}; |
Option 2: Reading from some config file the list of classes – letting DevOps to modify the config file
1 2 3 4 5 6 7 8 9 | var l = new List<IExchangeRates[]>;foreach(var line in File.ReadAllLines(“myListOfExchangeRates.txt”){IExchangeRates r= Activator.CreateInstance(Type.GetType(line)) as IExchangeRates ;l.Add ( r );} |
Option 3: Reflection – in the current assembly or in all assemblies to load the classes that implements the interface to load the data
01 02 03 04 05 06 07 08 09 10 | var typeToFound = typeof(IExchangeRates);Assembly a = Assembly.GetExecutingAssembly();var types = a.GetTypes().Where(it=>it.IsPublic).Where(it => it.GetInterface(typeToFound.FullName)!=null).ToArray();foreach(var t in types){recognizes.Add(Activator.CreateInstance(t)as IExchangeRates);} |
Option4 Load as plugins
use the library from https://github.com/natemcmaster/DotNetCorePlugins/blob/master/samples/hello-world/HostApp/Program.cs and there are 2 lines , basically:
1 2 | var loader = new LoadExchangeProviders("plugins");var exchange = loader.LoadExchangeProviders().ToArray(); |
Infovalutar
And one hour passes...(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
( You can see the sources at https://github.com/ignatandrei/InfoValutar/ )
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