1. A method for handling events in compositional applications represented as processing graphs, comprising: receiving an event notification from an execution environment; modifying a planning domain according to the event notification; generating, using a processor of a computer, a new processing graph for a previously deployed first processing graph by using machine code executable by the computer to process the modified planning domain; determining if the new processing graph is different than the previously deployed first processing graph; and if the processing graphs are different: deploying the new processing graph and replacing the previously deployed first processing graph with the newly deployed processing graph, wherein the event notification is triggered in response to a new data source identified by a previously deployed second processing graph, wherein the event notification itself includes a component description and instructions to add the component description to the planning domain.