Updated Use Case Specification: Web Crawler (markdown)

Use-Case-Specification:-Web-Crawler.md

@@ -1,20 +1,31 @@
 # Use-Case Specification: Web Crawler
 ## 1. Use-Case: Web Crawler
 ### 1.1 Brief Description
-
+The web crawler is an important component of our project. In this Use-Case-Specification we specify the main task of this component: Crawling predefined webpages for current prices and saving them into a database.
 
 ## 2. Flow of Events
 ### Activity Diagram
 ![activity diagram](https://github.com/Mueller-Patrick/Betterzon/blob/master/doku/AC_Crawler.png)
 
+At the very beginning the crawler process reads it's configuration file. If it's invalid, the process will terminate.
+If not, the crawler will check if the specified Shop is already present in the database. If not, it will create the entry and continue with fetching all products from a certain category.
+For every product in that list the following will be done:
+- Check if the product is available on amazon.
+-- If not, the product is discarded
+- Check if the product is in the database
+-- If not, it is added
+- Add the fetched price to the price database
+If all fetched products are processed, the process is terminated.
 
 ## 3. Special Requirements
+TBD
 
 ## 4. Preconditions
-### 4.1 The user has to be logged in
-
+### 4.1 The Database has to accept connections
+### 4.2 A configuration file has to be in place
 
 ## 5. Postconditions
+TBD
 
 ## 6. Function Points
 [tbd]