Development status Active Operating system | ||
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Developer(s) Apache Software Foundation Stable release 6.4.1 / February 6, 2017 (2017-02-06) | ||
Apache Lucene is a free and open-source information retrieval software library, originally written completely in Java by Doug Cutting. It is supported by the Apache Software Foundation and is released under the Apache Software License.
Contents
Lucene has been ported to other programming languages including Object Pascal, Perl, C#, C++, Python, Ruby and PHP.
History
Doug Cutting originally wrote Lucene in 1999. 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.
Lucene formerly included a number of sub-projects, such as Lucene.NET, Mahout, Tika and Nutch. These three are now independent top-level projects.
In March 2010, the Apache Solr search server joined as a Lucene sub-project, merging the developer communities.
Version 4.0 was released on October 12, 2012.
The latest version of Lucene is 6.4.1 which was released on February 6, 2017.
Features and common use
While suitable for any application that requires full text indexing and searching capability, Lucene has been widely recognized for its utility in the implementation of Internet search engines and local, single-site searching.
Lucene has also been used to implement recommendation systems. For example, Lucene's 'MoreLikeThis' Class can generate recommendations for similar documents. In a comparison of the term vector-based similarity approach of 'MoreLikeThis' with citation-based document similarity measures, such as Co-citation and Co-citation Proximity Analysis Lucene's approach excelled at recommending documents with very similar structural characteristics and more narrow relatedness. In contrast, citation-based document similarity measures, tended to be more suitable for recommending more broadly related documents, meaning citation-based approaches may be more suitable for generating serendipitous recommendations, as long as documents to be recommended contain in-text citations.
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, Mind Maps, 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
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:
Users
For a list of companies that use Lucene (rather than extend), see Lucene's "Powered By" page. As an example, Twitter is using Lucene for its real time search.