Lucene example source code file (ReadTokensTask.java)

This example Lucene source code file (ReadTokensTask.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

docmaker, document, exception, io, numericfield, override, override, reader, reader, readtokenstask, reusablestringreader, string, string, tokenstream, tokenstream, util

The Lucene ReadTokensTask.java source code

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

/**
 * 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.Reader;
import java.util.List;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.benchmark.byTask.PerfRunData;
import org.apache.lucene.benchmark.byTask.feeds.DocMaker;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Fieldable;
import org.apache.lucene.document.NumericField;

/**
 * Simple task to test performance of tokenizers.  It just
 * creates a token stream for each field of the document and
 * read all tokens out of that stream.
 */
public class ReadTokensTask extends PerfTask {

  public ReadTokensTask(PerfRunData runData) {
    super(runData);
  }

  private int totalTokenCount = 0;
  
  // volatile data passed between setup(), doLogic(), tearDown().
  private Document doc = null;
  
  @Override
  public void setup() throws Exception {
    super.setup();
    DocMaker docMaker = getRunData().getDocMaker();
    doc = docMaker.makeDocument();
  }

  @Override
  protected String getLogMessage(int recsCount) {
    return "read " + recsCount + " docs; " + totalTokenCount + " tokens";
  }
  
  @Override
  public void tearDown() throws Exception {
    doc = null;
    super.tearDown();
  }

  @Override
  public int doLogic() throws Exception {
    List<Fieldable> fields = doc.getFields();
    Analyzer analyzer = getRunData().getAnalyzer();
    int tokenCount = 0;
    for(final Fieldable field : fields) {
      if (!field.isTokenized() || field instanceof NumericField) continue;
      
      final TokenStream stream;
      final TokenStream streamValue = field.tokenStreamValue();

      if (streamValue != null) 
        stream = streamValue;
      else {
        // the field does not have a TokenStream,
        // so we have to obtain one from the analyzer
        final Reader reader;			  // find or make Reader
        final Reader readerValue = field.readerValue();

        if (readerValue != null)
          reader = readerValue;
        else {
          String stringValue = field.stringValue();
          if (stringValue == null)
            throw new IllegalArgumentException("field must have either TokenStream, String or Reader value");
          stringReader.init(stringValue);
          reader = stringReader;
        }
        
        // Tokenize field
        stream = analyzer.reusableTokenStream(field.name(), reader);
      }

      // reset the TokenStream to the first token
      stream.reset();

      while(stream.incrementToken())
        tokenCount++;
    }
    totalTokenCount += tokenCount;
    return tokenCount;
  }

  /* Simple StringReader that can be reset to a new string;
   * we use this when tokenizing the string value from a
   * Field. */
  ReusableStringReader stringReader = new ReusableStringReader();

  private final static class ReusableStringReader extends Reader {
    int upto;
    int left;
    String s;
    void init(String s) {
      this.s = s;
      left = s.length();
      this.upto = 0;
    }
    @Override
    public int read(char[] c) {
      return read(c, 0, c.length);
    }
    @Override
    public int read(char[] c, int off, int len) {
      if (left > len) {
        s.getChars(upto, upto+len, c, off);
        upto += len;
        left -= len;
        return len;
      } else if (0 == left) {
        return -1;
      } else {
        s.getChars(upto, upto+left, c, off);
        int r = left;
        left = 0;
        upto = s.length();
        return r;
      }
    }
    @Override
    public void close() {}
  }
}