Best design pattern to create client that can consume different APIs?

I have four different data sources each data source have has its own implementation. One can be Web service with its own methods and another can be a file on the system. I need to Create a consumer that process products from different data sources of different data formats and insert them into database. I tried to use the Adapter design pattern but i feel that it is not good enough and there can be more efficient approach, here is my implementation to the problem http://codepad.org/4M1sCDlm