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Lucene

Developer(s)	Apache Software Foundation
Stable release	3.6 / April 12, 2012; 2 months ago  (2012-04-12)
Development status	Active
Written in	Java
Operating system	Cross-platform
Type	Search and index
License	Apache License 2.0
Website	lucene.apache.org

Apache Lucene is a free/open source information retrieval software library, originally created in Java by Doug Cutting. It is supported by the Apache Software Foundation and is released under the Apache Software License.

Lucene has been ported to other programming languages including Delphi, Perl, C#, C++, Python, Ruby, and PHP^[1].

History[link]

Lucene was originally written by Doug Cutting in 1999.^[2] It was initially available for download from its home at the SourceForge web site. It joined the Apache Software Foundation's Jakarta family of open source Java products in September 2001 and became its own top-level Apache project in February 2005. Until recently, it included a number of sub-projects, such as Lucene Java, Droids, Lucene.Net, Lucy, Mahout, Solr, Nutch, Open Relevance Project, PyLucene, and Tika. Solr has been merged into the Lucene project itself and Mahout, Nutch and Tika have been moved to be independent top-level projects.

Features and common use[link]

While suitable for any application which requires full text indexing and searching capability, Lucene has been widely recognized ^[3][4] for its utility in the implementation of Internet search engines and local, single-site searching.

At the core of Lucene's logical architecture is the idea of a document containing fields of text. This flexibility allows Lucene's API to be independent of the file format. Text from PDFs, HTML, Microsoft Word, and OpenDocument documents, as well as many others (except images), can all be indexed as long as their textual information can be extracted.

Lucene-based projects[link]

Lucene itself is just an indexing and search library and does not contain crawling and HTML parsing functionality. However, several projects extend Lucene's capability:

• Apache Nutch provides web crawling and HTML parsing
• Apache Solr – an enterprise search server
• ElasticSearch – an enterprise search server
• Compass – a Java Search Engine Framework

Users[link]

For a list of companies that use Lucene (rather than extend), see Lucene's 'Powered By' page.^[5] As an example Twitter is using Lucene for its real time search^[6]

See also[link]

Free software portal

• Lucene.net
• Hadoop
• Hibernate search
• Xapian
• Sphinx (search engine)
• LGTE
• Information extraction
• Text mining
• eGranary Digital Library

References[link]

Bibliography[link]

External links[link]

• Official website
• List of Lucene Ports (or Implementations) in Other Languages on the Apache wiki
• Introductory article with Java code for search (This page is on Internet Archive) on Wikipedia data
• Lucene FAQ
• Luke (Lucene Index Toolbox)
• LuSql High performance JDBC-to-Lucene index builder
• ElasticSearch – A Distributed, Highly Available, RESTful Search Engine