With Oozie we can use fork and join to launch parallel actions. All launched parallel actions will join a final Action. The Final action will begin to work when all parallel actions are finished successfully.
Is there an elegant solution for having the same feature for processors with nifi ?
NiFi is not really a parallel job execution framework, it is a data flow tool that moves data from one place to another and can perform operations on that data along the way. There is a way to parallelize some operations such as the List+Fetch model, where a processor on the primary node performs a listing, for example list the contents of an HDFS directory, then distribute those results to all the nodes in the cluster to perform the fetch in parallel (see this post https://community.hortonworks.com/articles/16120/how-do-i-distribute-data-across-a-nifi-cluster.html..., but there is not a concept of final action.