Xapian is an Open Source Search Engine Library, released under the GPL. It's written in C++, with bindings to allow use from Perl, Python, PHP, Java, Tcl, C#, and Ruby. Xapian is a highly adaptable toolkit which allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also supports a rich set of boolean query operators.
Ключевые особенности и характеристики Xapian
· Highly portable - runs on Linux, Mac OS X, FreeBSD, NetBSD, OpenBSD, Solaris, HP-UX, Tru64, IRIX, and probably other Unix platforms, as well as Microsoft Windows. · Written in C++. Perl bindings are available in the module Search::Xapian on CPAN. Java JNI bindings are included in the xapian-bindings module. It also support SWIG which can generate bindings for many languages. At present those for Python, PHP, TCL, C#, and Ruby are working. · Ranked probablistic search - important words get more weight than unimportant words, so the most relevant documents are more likely to come near the top of the results list. · Relevance feedback - given one or more documents, Xapian can suggest the most relevant index terms to expand a query, suggest related documents, categorise documents, etc. · Phrase and proximity searching - users can search for words occuring in an exact phrase or within a specified number of words, either in a specified order, or in any order. · Full range of structured boolean search operators ("stock NOT market", etc). The results of the boolean search are ranked by the probablistic weights. Boolean filters can also be applied to restrict a probabilistic search. · Supports stemming of search terms (e.g. a search for "football" would match documents which mention "footballs" or "footballer"). This helps to find relevant documents which might otherwise be missed. Stemmers are currently included for Danish, Dutch, English, Finnish, French, German, Italian, Norwegian, Portuguese, Russian, Spanish, and Swedish. · Wildcard search is supported (e.g. "xap*"). · Supports database files > 2GB - essential for scaling to large document collections. · Platform independent data formats - you can build a database on one machine and search it on another. · Allows simultaneous update and searching. New documents become searchable right away.
