Apache Lucene is a powerful, open-source search library that provides full-text search capabilities. It enables developers to build applications with sophisticated search features, including indexing, querying, and ranking of textual data. Lucene is written in Java and is widely used in various domains, such as enterprise search, e-commerce platforms, and content management systems.

• **Full-Text Search:** Lucene's core functionality is full-text search, which allows for efficient searching of textual data based on keywords, phrases, and other criteria.
• **Indexing:** It provides mechanisms for indexing documents, extracting relevant terms, and storing them in an optimized data structure for fast retrieval.
• **Querying:** Lucene offers a rich query language for formulating complex search queries, including Boolean operators, wildcards, proximity searches, and more.
• **Ranking:** It includes algorithms for ranking search results based on relevance, allowing you to present the most relevant results to users.
• **Scalability:** Lucene is designed to handle large volumes of data and scale efficiently to meet the demands of high-traffic applications.
• **Extensibility:** Its modular architecture allows for customization and extension, enabling developers to tailor Lucene's behavior to their specific needs.

• **Powerful Search Capabilities:** Lucene provides a robust and feature-rich platform for implementing full-text search functionality in your applications.
• **High Performance:** Its optimized indexing and search algorithms deliver fast and efficient search results, even on large datasets.
• **Scalability:** Lucene can handle massive volumes of data and scale horizontally across multiple machines, making it suitable for enterprise-level applications.
• **Flexibility:** Its extensible architecture allows for customization and integration with other tools and technologies.
• **Open Source:** Lucene is an open-source project with a vibrant community, fostering collaboration and innovation.

1. **Indexing Documents (Java):**

```java import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.document.*; import org.apache.lucene.index.*; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory;

// Create an index writer Directory directory = FSDirectory.open(Paths.get(“/path/to/index”)); IndexWriterConfig config = new IndexWriterConfig(new StandardAnalyzer()); IndexWriter writer = new IndexWriter(directory, config);

// Create a document Document doc = new Document(); doc.add(new TextField(“title”, “My Document”, Field.Store.YES)); doc.add(new TextField(“content”, “This is the content of my document.”, Field.Store.YES));

// Add the document to the index writer.addDocument(doc);

// Commit changes and close the writer writer.commit(); writer.close(); ```

2. **Searching the Index (Java):**

```java import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.queryparser..lucene.search.*; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory;

// Create an index reader Directory directory = FSDirectory.open(Paths.get(“/path/to/index”)); IndexReader reader = DirectoryReader.open(directory); IndexSearcher searcher = new IndexSearcher(reader);

// Parse a query QueryParser parser = new QueryParser(“content”, new StandardAnalyzer()); Query query = parser.parse(“document”);

// Search the index TopDocs results = searcher.search(query, 10); // Retrieve top 10 results

// Process the search results for (ScoreDoc scoreDoc : results.scoreDocs) {

   Document doc = searcher.doc(scoreDoc.doc);
   System.out.println(doc.get("title"));

// Close the reader reader.close(); ```

These examples demonstrate basic indexing and searching operations using the Lucene Java API.

• **Apache Lucene Official Website:** s://lucene.apache.org/(https://lucene.apache.org/)
• **Lucene GitHub Repository:** s://github.com/apache/lucene(https://github.com/apache/lucene)
• **Lucene Documentation:** s://lucene.apache.org/core/(https://lucene.apache.org/core/)