UpdateRequestProcessor is a mechinism in Solr to change the documents that are being submitted for indexing to Solr. They provide advanced functions such as language identification, duplicate detection, intelligent defaults, external text processing pipelines integration, and - most recently - dynamic schema definition.
UpdateRequestProcessor factories (a.k.a. Update Request Processors or URPs) can be chained and multiple chains can be defined for one Solr collection. A chain is assigned to a request handler with update.chain parameter that can be defined in the configuration file or passed as a part of the URL. For full syntax, see example solrconfig.xml or consult Solr WIKI.
Here, you will find the full set of UpdateRequestProcessor factories presented in their inheritance hierarchy. Abstract classes that you cannot use directly are marked with underlined italic. Clicking on the class name will open corresponding JavaDoc page.
Most of the UpdateRequestProcessor factories are located in solr-core-4.9.0.jar ( example/solr-webapp/webapp/WEB-INF/lib/ ), so any entry without a location indicated can be found in that jar.
LangDetectLanguageIdentifierUpdateProcessorFactory in solr-langid-4.9.0.jar ( dist/ )
TikaLanguageIdentifierUpdateProcessorFactory in solr-langid-4.9.0.jar ( dist/ )
UIMAUpdateRequestProcessorFactory in solr-uima-4.9.0.jar ( dist/ )
<processor class="solr.CustomUpdateRequestProcessorFactory">Only non-core URPs require full class name, including package name.