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Lucene example source code file (DirContentSource.java)

This example Lucene source code file (DirContentSource.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, comparator, dateformatinfo, dateformatinfo, file, file, io, ioexception, iterator, iterator, nomoredataexception, override, stack, string, string, text, util

The Lucene DirContentSource.java source code

package org.apache.lucene.benchmark.byTask.feeds;

/**
 * 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 org.apache.lucene.benchmark.byTask.utils.Config;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileFilter;
import java.io.FileReader;
import java.io.IOException;
import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.Locale;
import java.util.Stack;

/**
 * A {@link ContentSource} using the Dir collection for its input. Supports
 * the following configuration parameters (on top of {@link ContentSource}):
 * <ul>
 * <li>work.dir - specifies the working directory. Required if "docs.dir"
 * denotes a relative path (<b>default=work).
 * <li>docs.dir - specifies the directory the Dir collection. Can be set
 * to a relative path if "work.dir" is also specified (<b>default=dir-out).
 * </ul>
 */
public class DirContentSource extends ContentSource {

  private static final class DateFormatInfo {
    DateFormat df;
    ParsePosition pos;
  }
  
  public static class Iterator implements java.util.Iterator<File> {

    static class Comparator implements java.util.Comparator<File> {
      public int compare(File _a, File _b) {
        String a = _a.toString();
        String b = _b.toString();
        int diff = a.length() - b.length();

        if (diff > 0) {
          while (diff-- > 0) {
            b = "0" + b;
          }
        } else if (diff < 0) {
          diff = -diff;
          while (diff-- > 0) {
            a = "0" + a;
          }
        }

        /* note it's reversed because we're going to push,
           which reverses again */
        return b.compareTo(a);
      }
    }

    int count = 0;

    Stack<File> stack = new Stack();

    /* this seems silly ... there must be a better way ...
       not that this is good, but can it matter? */

    Comparator c = new Comparator();

    public Iterator(File f) {
      push(f);
    }

    void find() {
      if (stack.empty()) {
        return;
      }
      if (!(stack.peek()).isDirectory()) {
        return;
      }
      File f = stack.pop();
      push(f);
    }

    void push(File f) {
      push(f.listFiles(new FileFilter() {

        public boolean accept(File file) {
          return file.isDirectory();
        }
      }));
      push(f.listFiles(new FileFilter() {

        public boolean accept(File file) {
          return file.getName().endsWith(".txt");
        }
      }));
      find();
    }

    void push(File[] files) {
      Arrays.sort(files, c);
      for(int i = 0; i < files.length; i++) {
        // System.err.println("push " + files[i]);
        stack.push(files[i]);
      }
    }

    public int getCount(){
      return count;
    }

    public boolean hasNext() {
      return stack.size() > 0;
    }
    
    public File next() {
      assert hasNext();
      count++;
      File object = stack.pop();
      // System.err.println("pop " + object);
      find();
      return object;
    }

    public void remove() {
      throw new RuntimeException("cannot");
    }

  }
  
  private ThreadLocal<DateFormatInfo> dateFormat = new ThreadLocal();
  private File dataDir = null;
  private int iteration = 0;
  private Iterator inputFiles = null;

  // get/initiate a thread-local simple date format (must do so 
  // because SimpleDateFormat is not thread-safe).
  private DateFormatInfo getDateFormatInfo() {
    DateFormatInfo dfi = dateFormat.get();
    if (dfi == null) {
      dfi = new DateFormatInfo();
      dfi.pos = new ParsePosition(0);
      // date format: 30-MAR-1987 14:22:36.87
      dfi.df = new SimpleDateFormat("dd-MMM-yyyy kk:mm:ss.SSS", Locale.US);
      dfi.df.setLenient(true);
      dateFormat.set(dfi);
    }
    return dfi;
  }
  
  private Date parseDate(String dateStr) {
    DateFormatInfo dfi = getDateFormatInfo();
    dfi.pos.setIndex(0);
    dfi.pos.setErrorIndex(-1);
    return dfi.df.parse(dateStr.trim(), dfi.pos);
  }

  @Override
  public void close() throws IOException {
    inputFiles = null;
  }
  
  @Override
  public DocData getNextDocData(DocData docData) throws NoMoreDataException, IOException {
    File f = null;
    String name = null;
    synchronized (this) {
      if (!inputFiles.hasNext()) { 
        // exhausted files, start a new round, unless forever set to false.
        if (!forever) {
          throw new NoMoreDataException();
        }
        inputFiles = new Iterator(dataDir);
        iteration++;
      }
      f = inputFiles.next();
      // System.err.println(f);
      name = f.getCanonicalPath()+"_"+iteration;
    }
    
    BufferedReader reader = new BufferedReader(new FileReader(f));
    String line = null;
    //First line is the date, 3rd is the title, rest is body
    String dateStr = reader.readLine();
    reader.readLine();//skip an empty line
    String title = reader.readLine();
    reader.readLine();//skip an empty line
    StringBuilder bodyBuf = new StringBuilder(1024);
    while ((line = reader.readLine()) != null) {
      bodyBuf.append(line).append(' ');
    }
    reader.close();
    addBytes(f.length());
    
    Date date = parseDate(dateStr);
    
    docData.clear();
    docData.setName(name);
    docData.setBody(bodyBuf.toString());
    docData.setTitle(title);
    docData.setDate(date);
    return docData;
  }
  
  @Override
  public synchronized void resetInputs() throws IOException {
    super.resetInputs();
    inputFiles = new Iterator(dataDir);
    iteration = 0;
  }

  @Override
  public void setConfig(Config config) {
    super.setConfig(config);
    
    File workDir = new File(config.get("work.dir", "work"));
    String d = config.get("docs.dir", "dir-out");
    dataDir = new File(d);
    if (!dataDir.isAbsolute()) {
      dataDir = new File(workDir, d);
    }

    inputFiles = new Iterator(dataDir);

    if (inputFiles == null) {
      throw new RuntimeException("No txt files in dataDir: " + dataDir.getAbsolutePath());
    }
  }

}

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