Note: You need to import “lucene-queryparser-common-4.2.1.jar” to use QueryParser. Usage Query q = new QueryParser(Version.LUCENE_42, "title", analyzer).parse(querystr) And for grammar, query language or query syntax is the main thing to issue with. As it is a lexer, it is to deal with grammar. So, the queryString as an input from us is interpreted as the query command that the lucence is meant to understand and execute the command. QueryParser is almost like a lexer that can interpret any sort of valid QueryString into a Lucence query. Different methods are available in the QueryParser Class so that we can easily go with the searching tasks using a wide range of searching options provided by the Lucene. QueryParser Class is the basic Class defined in Lucene Core particularly specialized for direct use for parsing queries and maintaining the queries. Note: You need to import “lucene-core-4.2.1.jar” to use IndexWriter. IndexWriter writer = new IndexWriter(index, config) IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_42, analyzer) Directory index = FSDirectory.open(new File("index-dir")) Usage Directory index = new RAMDirectory() IndexWriter Class is the basic Class defined in Lucene Core particularly specialized for direct use for creating index and maintaining the index.Different methods are available in the IndexWriter Class so that we can easily go with the indexing tasks. Finally, the StandardAnalyser post was aimed to demonstrate implementation contexts for the Standard Analyzer class in lucene. In the IndexWriter post, we went through the indexing, writing, searching and displaying steps for the indexing example.The QueryParser post was aimed to demonstrate different searching options and features that lucence facilitates through use the QueryParser class from lucene. Next were QueryParser and StandardAnalyzer. We went through three of the important classes to go with for the Indexing process in the previous three examples. Note: You need to import both jar files of lucene-analyzers-common-x.x.x and lucene-queryparser-x.x.x along with lucene-core-x.x.x jar file to implement this Lucene Example. The IndexWriter indexes the each document data using the configuration of IndexWriterConfig into the index directory. The document containing the fields are analysed using a StandardAnalyser. Different fields are defined into the document object.
Lucene Indexing processes the input data or document as per the nature of the fields defined in Document Object. So, Lucene Indexing is the prime intentional objective of Lucene core. The prime key for indexing and search technology in lucene is to go with indexing using index directory. Talking about Lucence core, it is particularly aimed to provide Java-based indexing and search technology, as well as spellchecking, hit highlighting and advanced analysis/tokenization capabilities. This is like why we create table of index or table of contents in our books.Īpache Lucene is an open-source search-support project recently working under Lucene core, solr, pyLucene and open revelence project. Indexing literally refers the process of classifying by providing a system of indexes so as to make items easier to access, retrieve or search from the whole source of information.
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