Java tutorial
package lucene.demo.search; /* * 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.IOException; import java.io.InputStreamReader; import java.nio.charset.StandardCharsets; import java.text.ParseException; import java.util.*; import lucene.demo.business.Hotel; import lucene.demo.business.HotelDatabase; 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.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig; 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.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.util.Version; /** Simple command-line based search demo. */ public class FileSearcher { private static HotelDatabase hotels; private static String indexPath; private static final int DISPLAY = 10; public FileSearcher(String index, HotelDatabase hotels) { this.hotels = hotels; indexPath = index; } public boolean search() throws IOException, ParseException { // field from the indexed file we are searching String field = "content"; IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(indexPath))); IndexSearcher searcher = new IndexSearcher(reader); Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_48); BufferedReader in = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8)); org.apache.lucene.queryparser.classic.QueryParser parser = new org.apache.lucene.queryparser.classic.QueryParser( Version.LUCENE_48, field, analyzer); // prompt user for stuff to remove System.out.println("I want to remove reviews with(Enter to end): "); String line = in.readLine(); if (line == null || line.length() == -1) { return false; } line = line.trim(); if (line.length() == 0) { return false; } Query query = null; try { query = parser.parse(line); } catch (org.apache.lucene.queryparser.classic.ParseException e) { e.printStackTrace(); } System.out.println("Searching for: " + query.toString(field)); doPagingSearch(in, searcher, query); reader.close(); return true; } public void doPagingSearch(BufferedReader in, IndexSearcher searcher, Query query) throws IOException { TopDocs results = searcher.search(query, hotels.getTotalReviews()); ScoreDoc[] hits = results.scoreDocs; int numTotalHits = results.totalHits; System.out.println(numTotalHits + " total matching documents"); // System.out.println("Before Removal \n"); // displayTop(DISPLAY); ArrayList<Hotel> hotelsBeforeRemoval = hotels.getHotels(); HashMap<Integer, Float> hotelHash = new HashMap<Integer, Float>(); for (Hotel hotel : hotelsBeforeRemoval) { hotelHash.put(hotel.getId(), hotel.getOverallRating()); } removeReviews(searcher, query, hits); // System.out.println("After Removal \n"); System.out.println("Top 10 Hotelsa"); displayTop(DISPLAY); System.out.println("Greatest changes \n"); displayBiggestChanges(hotelHash, DISPLAY); } private void removeReviews(IndexSearcher searcher, Query query, ScoreDoc[] hits) throws IOException { for (int i = 0; i < hits.length; i++) { Document doc = searcher.doc(hits[i].doc); Integer rating = Integer.parseInt(doc.get("rating")); Integer hotelID = Integer.parseInt(doc.get("hotelID")); Hotel hotel = hotels.getHotel(hotelID); hotel.removeReview(rating); } removeDocs(query); } private void removeDocs(Query query) throws IOException { Directory dir = FSDirectory.open(new File(indexPath)); Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_48); IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_48, analyzer); iwc.setOpenMode(IndexWriterConfig.OpenMode.CREATE_OR_APPEND); IndexWriter writer = new IndexWriter(dir, iwc); writer.deleteDocuments(query); writer.commit(); writer.close(); } public void displayTop(int numToDisplay) { ArrayList<Hotel> allHotels = hotels.getHotels(); Collections.sort(allHotels, new Comparator<Hotel>() { @Override public int compare(Hotel o1, Hotel o2) { if (o1.getOverallRating() > o2.getOverallRating()) return -1; else return 1; } }); for (int i = 0; i < numToDisplay; i++) { System.out.println((i + 1) + ". " + allHotels.get(i)); } System.out.println(""); } /** * This function will print the top positive changed hotels and the top * negative changed hotels. * @param hotelsOriginal the hotel data before removing some reviews * @param numToDisplay how many of each to print */ public void displayBiggestChanges(HashMap<Integer, Float> hotelsOriginal, int numToDisplay) { ArrayList<Hotel> afterRemoval = hotels.getHotels(); for (Hotel hotel : afterRemoval) { float change = hotel.getOverallRating() - hotelsOriginal.get(hotel.getId()); hotel.setChangeAfterRemoval(change); } Collections.sort(afterRemoval, new Comparator<Hotel>() { @Override public int compare(Hotel o1, Hotel o2) { return Float.compare(o2.getChangeAfterRemoval(), o1.getChangeAfterRemoval()); // if (o1.getChangeAfterRemoval() > o2.getChangeAfterRemoval()) // return -1; // else // return 1; } }); System.out.println("Hotels with Highest Positive Change"); for (int i = 0; i < numToDisplay; i++) { System.out.println((i + 1) + ". " + afterRemoval.get(i) + "\t changed " + afterRemoval.get(i).getChangeAfterRemoval()); } System.out.println(""); Collections.sort(afterRemoval, new Comparator<Hotel>() { @Override public int compare(Hotel o1, Hotel o2) { return Float.compare(o1.getChangeAfterRemoval(), o2.getChangeAfterRemoval()); // if (o1.getChangeAfterRemoval() > o2.getChangeAfterRemoval()) // return 1; // else // return -1; } }); System.out.println("Hotels with Highest Negative Change"); for (int i = 0; i < numToDisplay; i++) { System.out.println((i + 1) + ". " + afterRemoval.get(i) + "\t changed " + afterRemoval.get(i).getChangeAfterRemoval()); } System.out.println(""); } }