There are quite a few options when it comes to importing data into Solr. In this section, we'll examine a few of those, and then follow up with interaction examples. Details on specific formats, such as Solr's Update-XML, will come later.
The following diagram represents the high-level workflow of the indexing process in Solr. In addition to the predefined importing mechanisms, you can also build custom import handlers. Before generating the index, Solr uses the field definitions and other configurations from schema.xml and solrconfig.xml to process the data for each field.
Most applications interact with Solr over HTTP. This can either be done using a typical HTTP client, or indirectly via a Solr integration API such as SolrJ or Sunspot. Such APIs are discussed in Chapter 9, Integrating Solr.