Java tutorial
package indexer; /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.Date; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.index.IndexReader; import org.apache.lucene.queryparser.classic.QueryParser; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.Query; import org.apache.lucene.search.ScoreDoc; import org.apache.lucene.search.TopDocs; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.util.Version; /** Simple command-line based search demo. */ public class SearchFiles { private SearchFiles() { } /** Static method that reads the indices from the query and returns orderedlist of candidate documents * @throws Exception */ public static String[] paths(String queryString) throws Exception { /* String usage = "Usage:\tjava org.apache.lucene.demo.SearchFiles [-index dir] [-field f] [-repeat n] [-queries file] [-query string] [-raw] [-paging hitsPerPage]\n\nSee http://lucene.apache.org/core/4_1_0/demo/ for details."; if (args.length > 0 && ("-h".equals(args[0]) || "-help".equals(args[0]))) { System.out.println(usage); System.exit(0); } */ String index = "index"; String field = "contents"; String queries = null; int repeat = 0; boolean raw = false; // String queryString = null; int hitsPerPage = 10; /* for(int i = 0;i < args.length;i++) { if ("-index".equals(args[i])) { index = args[i+1]; i++; } else if ("-field".equals(args[i])) { field = args[i+1]; i++; } else if ("-queries".equals(args[i])) { queries = args[i+1]; i++; } else if ("-query".equals(args[i])) { queryString = args[i+1]; i++; } else if ("-repeat".equals(args[i])) { repeat = Integer.parseInt(args[i+1]); i++; } else if ("-raw".equals(args[i])) { raw = true; } else if ("-paging".equals(args[i])) { hitsPerPage = Integer.parseInt(args[i+1]); if (hitsPerPage <= 0) { System.err.println("There must be at least 1 hit per page."); System.exit(1); } i++; } } */ IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(index))); IndexSearcher searcher = new IndexSearcher(reader); Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_40); QueryParser parser = new QueryParser(Version.LUCENE_40, field, analyzer); /* BufferedReader in = null; if (queries != null) { in = new BufferedReader(new InputStreamReader(new FileInputStream(queries), "UTF-8")); } else { in = new BufferedReader(new InputStreamReader(System.in, "UTF-8")); } QueryParser parser = new QueryParser(Version.LUCENE_40, field, analyzer); while (true) { if (queries == null && queryString == null) { // prompt the user System.out.println("Enter query: "); } String line = queryString != null ? queryString : in.readLine(); */ String line = queryString; if (line == null || line.length() == -1) { System.out.println("Null query"); System.exit(0); } line = line.trim(); if (line.length() == 0) { System.out.println("Null query"); System.exit(0); } Query query = parser.parse(line); System.out.println("Searching for: " + query.toString(field)); if (repeat > 0) { // repeat & time as benchmark Date start = new Date(); for (int i = 0; i < repeat; i++) { searcher.search(query, null, 100); } Date end = new Date(); System.out.println("Time: " + (end.getTime() - start.getTime()) + "ms"); } String[] paths = doPagingSearch(searcher, query, hitsPerPage, raw, queries == null && queryString == null); return paths; /* if (queryString != null) { break; } } reader.close(); */ } /** * This demonstrates a typical paging search scenario, where the search engine presents * pages of size n to the user. The user can then go to the next page if interested in * the next hits. * * When the query is executed for the first time, then only enough results are collected * to fill 5 result pages. If the user wants to page beyond this limit, then the query * is executed another time and all hits are collected. * @return * */ public static String[] doPagingSearch(IndexSearcher searcher, Query query, int hitsPerPage, boolean raw, boolean interactive) throws IOException { ArrayList<String> docPaths = new ArrayList<String>(); // Collect enough docs to show 5 pages TopDocs results = searcher.search(query, 5 * hitsPerPage); ScoreDoc[] hits = results.scoreDocs; int numTotalHits = results.totalHits; System.out.println(numTotalHits + " total matching documents"); int start = 0; int end = numTotalHits; // int end = Math.min(numTotalHits, hitsPerPage); // while (true) { if (end > hits.length) { // System.out.println("Only results 1 - " + hits.length +" of " + numTotalHits + " total matching documents collected."); // System.out.println("Collect more (y/n) ?"); /* String line = in.readLine(); if (line.length() == 0 || line.charAt(0) == 'n') { break; } */ hits = searcher.search(query, numTotalHits).scoreDocs; } // end = Math.min(hits.length, start + hitsPerPage); for (int i = start; i < end; i++) { if (raw) { // output raw format System.out.println("doc=" + hits[i].doc + " score=" + hits[i].score); continue; } Document doc = searcher.doc(hits[i].doc); String path = doc.get("path"); if (path != null) { docPaths.add(path); //Add to arraylist of candidate document paths // System.out.println((i+1) + ". " + path); String title = doc.get("title"); if (title != null) { System.out.println(" Title: " + doc.get("title")); } } else { System.out.println((i + 1) + ". " + "No path for this document"); } } /* if (!interactive || end == 0) { break; } if (numTotalHits >= end) { boolean quit = false; while (true) { System.out.print("Press "); if (start - hitsPerPage >= 0) { System.out.print("(p)revious page, "); } if (start + hitsPerPage < numTotalHits) { System.out.print("(n)ext page, "); } System.out.println("(q)uit or enter number to jump to a page."); String line = in.readLine(); if (line.length() == 0 || line.charAt(0)=='q') { quit = true; break; } if (line.charAt(0) == 'p') { start = Math.max(0, start - hitsPerPage); break; } else if (line.charAt(0) == 'n') { if (start + hitsPerPage < numTotalHits) { start+=hitsPerPage; } break; } else { int page = Integer.parseInt(line); if ((page - 1) * hitsPerPage < numTotalHits) { start = (page - 1) * hitsPerPage; break; } else { System.out.println("No such page"); } } } if (quit) break; end = Math.min(numTotalHits, start + hitsPerPage); } }*/ String[] paths = new String[docPaths.size()]; docPaths.toArray(paths); return paths; } }