Java tutorial
/* * 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. */ package ru.npopm.dep715.searchdocs.lucene; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.nio.charset.StandardCharsets; import java.nio.file.FileVisitResult; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.SimpleFileVisitor; import java.nio.file.attribute.BasicFileAttributes; import java.util.Date; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.document.LongPoint; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; import org.apache.lucene.document.StringField; import org.apache.lucene.document.TextField; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.index.IndexWriterConfig.OpenMode; import org.apache.lucene.index.Term; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.slf4j.LoggerFactory; import ru.npopm.dep715.searchdocs.gui.MainController; /** * Index all text files under a directory. * <p> * This is a command-line application demonstrating simple Lucene indexing. Run * it with no command-line arguments for usage information. */ public class IndexFiles { // private static long operationTime; // public static long getOperationTime() { // return operationTime; // } private static final org.slf4j.Logger LOG = LoggerFactory.getLogger(IndexFiles.class); public static boolean startIndexDocs(String indexPath, boolean create, String docDir) { Path docsPath = Paths.get(docDir); try { if (!Files.isReadable(docsPath)) { System.out.println("Document directory '" + docsPath.toAbsolutePath() + "' does not exist or is not readable, please check the path"); return false; } System.out.println("Indexing to directory '" + indexPath + "'..."); Directory dir = FSDirectory.open(Paths.get(indexPath)); Analyzer analyzer = new StandardAnalyzer(); IndexWriterConfig iwc = new IndexWriterConfig(analyzer); if (create) { // Create a new index in the directory, removing any // previously indexed documents: iwc.setOpenMode(IndexWriterConfig.OpenMode.CREATE); } else { // Add new documents to an existing index: iwc.setOpenMode(IndexWriterConfig.OpenMode.CREATE_OR_APPEND); System.out.println("CREATE_OR_APPEND"); } // Optional: for better indexing performance, if you // are indexing many documents, increase the RAM // buffer. But if you do this, increase the max heap // size to the JVM (eg add -Xmx512m or -Xmx1g): // // iwc.setRAMBufferSizeMB(256.0); IndexWriter writer = new IndexWriter(dir, iwc); indexDocs(writer, docsPath); // NOTE: if you want to maximize search performance, // you can optionally call forceMerge here. This can be // a terribly costly operation, so generally it's only // worth it when your index is relatively static (ie // you're done adding documents to it): // // writer.forceMerge(1); writer.close(); } catch (IOException e) { System.out.println(" caught a " + e.getClass() + "\n with message: " + e.getMessage()); } return true; } /** * Indexes the given file using the given writer, or if a directory is * given, recurses over files and directories found under the given * directory. * * NOTE: This method indexes one document per input file. This is slow. For * good throughput, put multiple documents into your input file(s). An * example of this is in the benchmark module, which can create "line doc" * files, one document per line, using the * <a href="../../../../../contrib-benchmark/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.html" * >WriteLineDocTask</a>. * * @param writer Writer to the index where the given file/dir info will be * stored * @param path The file to index, or the directory to recurse into to find * files to index * @throws IOException If there is a low-level I/O error */ private static void indexDocs(final IndexWriter writer, Path path) throws IOException { if (Files.isDirectory(path)) { Files.walkFileTree(path, new SimpleFileVisitor<Path>() { @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { try { indexDoc(writer, file.toFile(), attrs.lastModifiedTime().toMillis()); } catch (IOException ignore) { // don't index files that can't be read. } return FileVisitResult.CONTINUE; } }); } else { indexDoc(writer, path.toFile(), Files.getLastModifiedTime(path).toMillis()); } } /** * Indexes a single document */ static void indexDoc(IndexWriter writer, File file, long lastModified) throws IOException { try (InputStream stream = new FileInputStream(file)) { // make a new, empty document Document doc = new Document(); // Add the path of the file as a field named "path". Use a // field that is indexed (i.e. searchable), but don't tokenize // the field into separate words and don't index term frequency // or positional information: Field pathField = new StringField("path", file.toString(), Field.Store.YES); doc.add(pathField); // Add the last modified date of the file a field named "modified". // Use a LongPoint that is indexed (i.e. efficiently filterable with // PointRangeQuery). This indexes to milli-second resolution, which // is often too fine. You could instead create a number based on // year/month/day/hour/minutes/seconds, down the resolution you require. // For example the long value 2011021714 would mean // February 17, 2011, 2-3 PM. doc.add(new LongPoint("modified", lastModified)); // Add the contents of the file to a field named "contents". Specify a Reader, // so that the text of the file is tokenized and indexed, but not stored. // Note that FileReader expects the file to be in UTF-8 encoding. // If that's not the case searching for special characters will fail. doc.add(new TextField("contents", new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8)))); if (writer.getConfig().getOpenMode() == OpenMode.CREATE) { // New index, so we just add the document (no old document can be there): System.out.println("adding " + file); writer.addDocument(doc); } else { // Existing index (an old copy of this document may have been indexed) so // we use updateDocument instead to replace the old one matching the exact // path, if present: System.out.println("updating " + file); // writer.deleteDocuments(new Term("path", file.toString())); writer.updateDocument(new Term("path", file.toString()), doc); } } } }