alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Lucene example source code file (SearchFiles.java)

This example Lucene source code file (SearchFiles.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

bufferedreader, bufferedreader, date, date, document, file, indexsearcher, io, ioexception, query, searchfiles, string, string, utf-8, utf-8, util

The Lucene SearchFiles.java source code

package org.apache.lucene.demo;

/**
 * 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.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.IndexReader;
import org.apache.lucene.queryParser.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() {}

  /** Simple command-line based search demo. */
  public static void main(String[] args) 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/java/4_0/demo.html 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++;
      }
    }
    
    IndexSearcher searcher = new IndexSearcher(FSDirectory.open(new File(index)));
    Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_31);

    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_31, field, analyzer);
    while (true) {
      if (queries == null && queryString == null) {                        // prompt the user
        System.out.println("Enter query: ");
      }

      String line = queryString != null ? queryString : in.readLine();

      if (line == null || line.length() == -1) {
        break;
      }

      line = line.trim();
      if (line.length() == 0) {
        break;
      }
      
      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");
      }

      doPagingSearch(in, searcher, query, hitsPerPage, raw, queries == null && queryString == null);

      if (queryString != null) {
        break;
      }
    }
    searcher.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.
   * 
   */
  public static void doPagingSearch(BufferedReader in, IndexSearcher searcher, Query query, 
                                     int hitsPerPage, boolean raw, boolean interactive) throws IOException {
 
    // 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 = 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) {
          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);
      }
    }
  }
}

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene SearchFiles.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.