Introduction
OpenSyllabus Client needs to interact with the Sakai's Server. OpenSyllabus used all the Sakai's platform services we needed, in addition of our own services.
RPC
RPC (Remote Procedure Call) is the Ajax workhorse of GWT.
GWT offers an easy-to-use RPC mechanism that makes it easy for the client-side code and the server-side code to communicate Java objects (serialized objects) back and forth using standard HTTP.
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Furthermore, OpenSyllabus could load complex data from the server by leveraging the GWT XML and JSON libraries.
REST based SData
OpenSyllabus Client uses REST based calls to SData services on the Sakai server.
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The SData service is called via a REST Servlet in Sakai. SData allows data exchanges in JSON format of information about site, resource, etc.) In order to parse JSON in GIT we have used the JSONParser from the GWT library.
Basic communication techniques
GWT also offers more basic communication techniques, including the standard Ajax asynchronous HTTP request to load simple text or HTML from the server.