.. include:: /includes.rst.txt

.. comments - headings

   # with overline, for parts
   * with overline, for chapters
   = for sections
   - for subsections
   ^ for subsubsections
   " for paragraphs



.. index:: pair: Searching; Special Character Handling

.. _lucene_integration_target:

Lucene integration and special character handling in Search
-----------------------------------------------------------

EDG uses the Apache Lucene library for indexing text.
A text index is built on system startup, if it does not already exist.
The indexer is using *Graph Listeners* and is updated in near real time as data changes.
Users with *administrator* privileges can rebuild the cache on demand using the *Cached Graphs* administration page (see :ref:`edg_administration_and_configuration`).


Changing to Lucene WhitespaceAnalyzer
"""""""""""""""""""""""""""""""""""""

By default, both *Search the EDG* and the EDG editor search panel use the Lucene index *StandardAnalyzer*.

The default *StandardAnalyzer* **drops** characters such as / and – while the *WhitespaceAnalyzer* preserves them.

To search over special characters (such as / ? and -), an *administrator* must enable the *WhitespaceAnalyzer* option in :ref:`edg_configuration_parameters`.
After making a change in analyzer, the administrator needs to rebuild the indices using *Text Indices* and *Search the EDG Index*.