book.Searcher.java Source code

Introduction

Here is the source code for book.Searcher.java

Source

package book;

/**
 * Copyright Manning Publications Co.
 *
 * Licensed 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 lan      
 */

import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.ParseException;
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.analysis.standard.StandardAnalyzer;

import java.io.File;
import java.io.IOException;

// From chapter 1

/**
 * This code was originally written for Erik's Lucene intro java.net article
 */
public class Searcher {

    public static void main(String[] args) throws IllegalArgumentException, IOException, ParseException {
        if (args.length != 2) {
            throw new IllegalArgumentException("Usage: java " + Searcher.class.getName() + " <index dir> <query>");
        }

        String indexDir = args[0]; // 1
        String q = args[1]; // 2

        search(indexDir, q);
    }

    public static void search(String indexDir, String q) throws IOException, ParseException {

        IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(indexDir).toPath()));
        IndexSearcher is = new IndexSearcher(reader);

        //alt: Directory dir = FSDirectory.open(new File(indexDir)); // 3
        //alt: IndexSearcher is = IndexSearcher(dir); // 3

        QueryParser parser = new QueryParser("contents", // 4
                new StandardAnalyzer()); // 4
        Query query = parser.parse(q); // 4
        long start = System.currentTimeMillis();
        TopDocs hits = is.search(query, 10); // 5
        long end = System.currentTimeMillis();

        System.err.println("Found " + hits.totalHits + // 6
                " document(s) (in " + (end - start) + // 6
                " milliseconds) that matched query '" + // 6
                q + "':"); // 6

        for (ScoreDoc scoreDoc : hits.scoreDocs) {
            Document doc = is.doc(scoreDoc.doc); // 7
            System.out.println(doc.get("fullpath")); // 8
        }

        //was: is.close(); // 9
    }
}

/*
 * #1 Parse provided index directory #2 Parse provided query string #3 Open
 * index #4 Parse query #5 Search index #6 Write search stats #7 Retrieve
 * matching document #8 Display filename #9 Close IndexSearcher
 */