Logging using Interceptors in Windsor Container

vinay — Thu, 19 Jun 2008 00:00:00 GMT

The Windsor container gives you a provision of adding behavior to components without having to change the components implementation. For example if you want to log whenever a method is called through your services class say CustomerService, you can assign an Interceptor for this particular component and add behavior when this component is called. Lets see how logging can be achieved for the CustomerService component.

First thing is to create a LogInterceptor.


    1 public class LogInterceptor : IInterceptor
    2 {
    3     public ILogger Logger;
    4 
    5     public LogInterceptor() { }
    6 
    7     public void Intercept(IInvocation invocation)
    8     {
    9         //Get the method name
   10         string methodName = invocation.GetConcreteMethod().Name;
   11 
   12         Log("Entering method: " + methodName);
   13         invocation.Proceed();
   14         Log("Leaving mehod: " + methodName);
   15     }
   16 
   17     private void Log(string log)
   18     {
   19         Logger.Info(log);
   20     }
   21 }

Here we are implementing the Intercept method of the IInterceptor interface. We are just getting the method name and logging it before the method is invoked and after its completion.

Here is the CustomerService class.


    1 public class CustomerService :  ICustomerService 
    2 {
    3     CustomerDAO custDAO=new CustomerDAO();
    4 
    5     public CustomerService() { }
    6 
    7     public virtual List<Customer> GetCustomers()
    8     {
    9         return custDAO.RetrieveCustomers();
   10     }
   11 }

The GetCustomers method just calls the DAO object to get a list of customers. Next we define the components in the services.config file so that the Interceptor is injected at runtime.


<configuration>
    <components>
        <component id="LogInterceptor"
              type="Rails.Services.LogInterceptor, Services"
              lifestyle="transient" />
        <component id="service.customer"
               type="Rails.Services.CustomerService, Services"
               service="Rails.Interfaces.ICustomerService, Interfaces">
            <interceptors>
                <interceptor>${LogInterceptor}interceptor>
            interceptors>
        component>
    components>
configuration>

Here we are adding a interceptor to the CustomerService class after defining the Interceptor.

Thats that. Now whenever the method is called for this particular component, it is automatically logged.

Vinay Rao | Castle Project

Logging using Interceptors in Windsor Container