HowTheExamplesWork.txt

Application entry point is the web.xml


1. When a user (a browser) requests a page from our domain it is handled by the web.xml.

2. In there the DispatcherServlet (the front controller in Spring MVC) takes the request and inspects the URL.

2.1 The FrontController (DispatcherServlet) first reads the test-context.xml
2.2 test-context.xml is the "configuration" file of the front controller
2.3 the dispatchedServlet reads the .xml file and finds <context:component-scan base-package="glasgow.teamproject.teamB" />. This tells him that YOU have used Annotation based controllers in the specific package
2.4 Therefore he now loads all of those controllers in his memory
2.5 He now has to decide which controller he has to invoke 
2.6 He looks at the @RequestMapping() annotation of each method in each controller
2.7 He compares the patterns in the @RequestMapping annotation with the incoming request
2.8 When he finds a match he makes a call to the method under it

3. Now OUR controller is in charge
3.1 The controller gets a call of the specific method under the matched by the frontController method
3.2 Inside the method we create a ModelAndView obj by specifying the name of the view which will be used to render the response 
3.3 We then add information to the object. We add it like we would add info in a dictionary by specifying a key-value pair and later get it as if we are getting data from a dictionary - with appropriate keys.
3.4 The method sends this ModelAndView object back to the frontController

4. The frontController will render the view
4.1 He uses the viewResolver finds the exact path of the view specified in the ModelAndView object
4.2 the VIEW does what it does how it does it :D (check out the view for more info)
4.3 He then sends the rendered view(= HTML ) as a response to the user




Q: What if the URL does not match any mapping?
A: Spring will return a response saying that no resource is available that URL