Apache Lucene is a

free and open-source Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

search engine A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a ...

software library In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and sub ...

, originally written in

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...

Doug Cutting Douglass Read Cutting is a software designer, advocate, and creator of open-source search technology. He founded two technology projects, Lucene, and Nutch, with Mike Cafarella. Both projects are now managed through the Apache Software Foundation ...

. It is supported by the

Apache Software Foundation The Apache Software Foundation (ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open source software projects. The ASF was formed from a group of developers of the ...

and is released under the Apache Software License. Lucene is widely used as a standard foundation for non-research search applications. Lucene has been ported to other programming languages including

Object Pascal Object Pascal is an extension to the programming language Pascal that provides object-oriented programming (OOP) features such as classes and methods. The language was originally developed by Apple Computer as ''Clascal'' for the Lisa Worksh ...

Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offic ...

, C#,

C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called ...

and PHP.

History

originally wrote Lucene in 1999. Lucene was his fifth search engine, having previously written two while at Xerox PARC, one at Apple, and a fourth at Excite. It was initially available for download from its home at the

SourceForge SourceForge is a web service that offers software consumers a centralized online location to control and manage open-source software projects and research business software. It provides source code repository hosting, bug tracking, mirroring ...

web site. It joined the Apache Software Foundation's

Jakarta Jakarta (; , bew, Jakarte), officially the Special Capital Region of Jakarta ( id, Daerah Khusus Ibukota Jakarta) is the capital city, capital and list of Indonesian cities by population, largest city of Indonesia. Lying on the northwest coa ...

family of open-source Java products in September 2001 and became its own top-level Apache project in February 2005. The name Lucene is Doug Cutting's wife's middle name and her maternal grandmother's first name. Lucene formerly included a number of sub-projects, such as Lucene.NET,

Mahout A mahout is an elephant rider, trainer, or keeper. Mahouts were used since antiquity for both civilian and military use. Traditionally, mahouts came from ethnic groups with generations of elephant keeping experience, with a mahout retaining h ...

, Tika and

Nutch Apache Nutch is a highly extensible and scalable open source web crawler software project. Features Nutch is coded entirely in the Java programming language, but data is written in language-independent formats. It has a highly modular architec ...

. These three are now independent top-level projects. In March 2010, the

Apache Solr Solr (pronounced "solar") is an open-source enterprise-search platform, written in Java. Its major features include full-text search, hit highlighting, faceted search, real-time indexing, dynamic clustering, database integration, NoSQL features a ...

search server joined as a Lucene sub-project, merging the developer communities. Version 4.0 was released on October 12, 2012. In March 2021, Lucene changed its logo, and

became a top level Apache project again, independent from Lucene.

Features and common use

While suitable for any application that requires full text indexing and searching capability, Lucene is recognized for its utility in the implementation of

Internet search engine A search engine is a software system designed to carry out web searches. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a l ...

s and local, single-site searching. Lucene includes a feature to perform a fuzzy search based on

edit distance In computational linguistics and computer science, edit distance is a string metric, i.e. a way of quantifying how dissimilar two strings (e.g., words) are to one another, that is measured by counting the minimum number of operations required to ...

. 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 Co-citation is the frequency with which two documents are ''cited'' together by other documents.. If at least one other document cites two documents in common, these documents are said to be ''co-cited''. The more co-citations two documents recei ...

and co-citation proximity analysis, Lucene's approach excelled at recommending documents with very similar structural characteristics and more narrow relatedness.M. Schwarzer, M. Schubotz, N. Meuschke, C. Breitinger, V. Markl, and B. Gipp, https://www.gipp.com/wp-content/papercite-data/pdf/schwarzer2016.pdf "Evaluating Link-based Recommendations for Wikipedia" in Proceedings of the 16th ACM/IEEE-CS Joint Conference on Digital Libraries (JCDL), New York, NY, USA, 2016, pp. 191-200. 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 Serendipity is an unplanned fortunate discovery. Serendipity is a common occurrence throughout the history of product invention and scientific discovery. Etymology The first noted use of "serendipity" was by Horace Walpole on 28 January 1754. I ...

recommendations, as long as documents to be recommended contain in-text citations.

Lucene-based projects

Lucene itself is just an indexing and search library and does not contain crawling and HTML

parsing Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from ...

functionality. However, several projects extend Lucene's capability: *

Apache Nutch Apache Nutch is a highly extensible and scalable open source web crawler software project. Features Nutch is coded entirely in the Java programming language, but data is written in language-independent formats. It has a highly modular archi ...

– provides web crawling and HTML parsing *

– an enterprise search server *

CrateDB CrateDB is a distributed SQL database management system that integrates a fully searchable document-oriented data store. It is open-source, written in Java, based on a shared-nothing architecture, and designed for high scalability. CrateDB i ...

– open source, distributed SQL database built on Lucene *

DocFetcher DocFetcher is a free and open source desktop search application. It runs on Windows, Mac OS X and Linux and is written in Java. The application has a graphical user interface, which is written using the Standard Widget Toolkits. The program i ...

– a

multiplatform In computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform software ...

desktop search application *

Elasticsearch Elasticsearch is a search engine based on the Lucene library. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents. Elasticsearch is developed in Java and is dual ...

– an enterprise search server released in 2010 * Kinosearch – a search engine written in

and C and a loose

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

of Lucene. The

Socialtext Socialtext Incorporated was a company based in Palo Alto, California, that produced enterprise social software for companies. It offered an integrated suite of wiki tools and social software applications, including microblogging, user profiles, ...

wiki software uses this search engine, and so does the MojoMojo wiki. It is also used by the Human Metabolome Database (HMDB) and the Toxin and Toxin-Target Database (T3DB). *

MongoDB MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the S ...

Atlas Search – a cloud-native enterprise search application based on MongoDB and Apache Lucene *

OpenSearch OpenSearch is a collection of technologies that allow the publishing of search results in a format suitable for syndication and aggregation. Introduced in 2005, it is a way for websites and search engines to publish search results in a standard ...

– an open source enterprise search server based on a fork of Elasticsearch 7 *

Swiftype Swiftype is a search and index company based in San Francisco, California, that provides search software for organizations, websites, and computer programs. Notable customers include AT&T, Dr. Pepper, Hubspot and TechCrunch. History Swiftype was ...

– an enterprise search startup based on Lucene

References

Bibliography

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External links

* {{Authority control

Lucene Apache Lucene is a free and open-source search engine software library, originally written in Java by Doug Cutting. It is supported by the Apache Software Foundation and is released under the Apache Software License. Lucene is widely used as ...