We are about to start with Activiti enterprise and we want to trigger Activiti workflows from alfresco when a document is uploaded to a certain folder (via a rule or behaviour).
I'm wondering if with the Activiti Share Connector the corresponding Java(script) API is provided to start Activiti processes from within Alfresco.
Yes, that is possible (I'm not sure if the javascript part is 1.4 or 1.5 - which isn't released yet).
Alternatively, the enterprise suite has a REST API that you can call from a java/javascript action easily (so you don't need to whole share connector if that's your only use case).