- Payment System

- They all must be queued if a user orders something
- The ordered item must be validated if it is being sold
- This should be done by a composite filter pattern (composite combined with filter)
An other pattern shall e.g. only book the item/money if the API gives positive reply
State-depending pattern?
- Different payment APIs exists
- Wernis API
- Request: GET,POST
- Response: Own format
- Primera API
Need special agreement here!- Request: POST
Response: Own format (?)
- (Paypal)
Has expensive fees for sender
Moneybookers 
- Request: GET
POST also?
- Response: XML
- Rambler?