It would be great if there was a SolrJ library that could connect to Solr's /export handler (
SOLR-5244) and perform streaming operations on the sorted result sets.
This ticket defines the base interfaces and implementations for the Streaming API. The base API contains three classes:
SolrStream: This represents a stream from a single Solr instance. It speaks directly to the /export handler and provides methods to read() Tuples and close() the stream
CloudSolrStream: This represents a stream from a SolrCloud collection. It speaks with Zk to discover the Solr instances in the collection and then creates SolrStreams to make the requests. The results from the underlying streams are merged inline to produce a single sorted stream of tuples.
Tuple: The data structure returned by the read() method of the SolrStream API. It is nested to support grouping and Cartesian product set operations.
Once these base classes are implemented it paves the way for building Decorator streams that perform operations on the sorted Tuple sets. For example: