Caching allows datasets to cache other URIs along with the one requested. For example, a Jython script is executed resulting in four datasets being calculated. Since the URI must only correspond to one dataset, only one of the datasets is used, but instead of throwing out the result, we keep them around in case the client wants to plot a related URI.
reset any internal storage, and any subsequent calls should return false to satisfies.
Set the DataSource's URI to this new one. This must be a URI where satisifies() is true.
return true if the DataSource is able to quickly resolve the data set.