Service Locator

Service Locator Pattern 

Gamma Categorization: Behavioral Design Pattern
Summary: Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates.

Sample Code

Problem: We want to get the service based on the interface.

Code

public interface IServiceLocator

{

T GetService<T>();

}

public class ServiceLocator : IServiceLocator

{

private IDictionary<object, object> services;

public ServiceLocator()

{

services = new Dictionary<object, object>();

this.services.Add(typeof(IStorageService), new CloudService());

this.services.Add(typeof(INetworkService), new WiFiService());

}

public T GetService<T>()

{

try

{

return (T)services[typeof(T)];

}

catch (KeyNotFoundException)

{

throw new ApplicationException("The requested service is not registered");

}

}

}

public interface IStorageService

{

void Store();

}

public class CloudService : IStorageService

{

public void Store()

{

System.Console.WriteLine("Saving file.");

}

}

public interface INetworkService

{

void Connect();

}

public class WiFiService : INetworkService

{

public void Connect()

{

System.Console.WriteLine("Connected to network.");

}

}

Usage

var serviceLocator = new ServiceLocator();

var storage = serviceLocator.GetService<IStorageService>();

var network = serviceLocator.GetService<INetworkService>();

storage.Store();

network.Connect();

Output

Saving file.

Connected to network.