2-Tier Cloud Architecture with maximized RIA and SimpleDB via minimized REST

To address the serious problems in Cloud application development such as complex architecture and WS API, highly running cost, poor UI and interaction and so on, we found that the problems stem from no using RIA's power fully and inappropriate functionality segmentation between client-side and server-side. That is, Web services, application logic and transaction logic are overly concentrated on the server side. We proposed 2-Tier Cloud-ARchitecture (2TCAR), which contains rich client tier based on RIA and server-side Cloud tier based on SimpleDB. Rich client tier is maximized to implement almost all functionalities of Cloud application and transaction logic; functionality in server-side Cloud tier is simplified only to implement data storage and query; communication between two tiers is also simplified via REST. In the article we researched corresponding technologies such as Cloud computing, Web services, REST, Flex in RIA and SimpleDB Cloud. Further, we presented how use Flex to implement UI presentation & interaction, transaction logic, REST requests & responses in rich client tier; we also described how to design SimpleDB Cloud in server-side Cloud tier, and communication between two tiers via REST. All research findings were applied into a Cloud application demo. The practice has shown that the 2TCAR is effective and valuable for Cloud application.