1. Design of an Online Voting System COMP 204, Spring 2001Adrian Ilie & Miguel A. Otaduy

2. Design Goals n handle elections of any kind at any administrative level n provide an easy-to-use on-line (web- based) interface n allow both a distributed and a stand- alone system organization

3. Example of a Distributed Election Consider an election day when elections are held at the national, state and local level. Voter data is retrieved from a census database, distributed in three locations.

4. Structure of a Node n election objects n user objects n managers DB n voters DB n candidates / answers DB n results DB

5. Connecting the Nodes (1) Having distributed databases means we have to search for data at different nodes...

6. Connecting the Nodes (2) … but it’s distributed!

7. Abstract User Class n implements authentication methods n serves as a superclass for concrete user types

8. User Type: Voter Created at engine with the database that contains the data about it.

9. User Type: Candidate All interactions are local.

10. User Type: Manager All interactions are local.

11. Menus and Actions

12. Election Class

13. Handling Election Types

14. Communication Issues

15. OFF-LINE Application n Creation of proxy objects for remote engines. The local chain is set at each node. Customers have to agree on what nodes are included in the global system. n Creation of election objects and the manager database. n Maintenance of voter and candidate databases.