content: /**
   * 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 org.apache.lucene.analysis.standard;
  
  import java.io.IOException;
  import java.io.Reader;
  
  import org.apache.lucene.analysis.Tokenizer;
  import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
  import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
  import org.apache.lucene.util.AttributeSource;
  import org.apache.lucene.util.Version;
  
  /** A grammar-based tokenizer constructed with JFlex
   *
   * <p> This should be a good tokenizer for most European-language documents:
   *
   * <ul>
   *   <li>Splits words at punctuation characters, removing punctuation. However, a 
   *     dot that's not followed by whitespace is considered part of a token.
   *   <li>Splits words at hyphens, unless there's a number in the token, in which case
   *     the whole token is interpreted as a product number and is not split.
   *   <li>Recognizes email addresses and internet hostnames as one token.
   * </ul>
   *
   * <p>Many applications have specific tokenizer needs.  If this tokenizer does
   * not suit your application, please consider copying this source code
   * directory to your project and maintaining your own grammar-based tokenizer.
   *
   * <a name="version"/>
   * <p>You must specify the required {@link Version}
   * compatibility when creating ClassicAnalyzer:
   * <ul>
   *   <li> As of 2.4, Tokens incorrectly identified as acronyms
   *        are corrected (see <a href="https://issues.apache.org/jira/browse/LUCENE-1068">LUCENE-1608</a>
   * </ul>
   * 
   * ClassicTokenizer was named StandardTokenizer in Lucene versions prior to 3.1.
   * As of 3.1, {@link StandardTokenizer} implements Unicode text segmentation,
   * as specified by UAX#29.
   */
  
  public final class ClassicTokenizer extends Tokenizer {
    /** A private instance of the JFlex-constructed scanner */
    private StandardTokenizerInterface scanner;
  
    public static final int ALPHANUM          = 0;
    public static final int APOSTROPHE        = 1;
    public static final int ACRONYM           = 2;
    public static final int COMPANY           = 3;
    public static final int EMAIL             = 4;
    public static final int HOST              = 5;
    public static final int NUM               = 6;
    public static final int CJ                = 7;
  
    /**
     * @deprecated this solves a bug where HOSTs that end with '.' are identified
     *             as ACRONYMs.
     */
    @Deprecated
    public static final int ACRONYM_DEP       = 8;
    
    /** String token types that correspond to token type int constants */
    public static final String [] TOKEN_TYPES = new String [] {
      "<ALPHANUM>",
      "<APOSTROPHE>",
      "<ACRONYM>",
      "<COMPANY>",
      "<EMAIL>",
      "<HOST>",
      "<NUM>",
      "<CJ>",
      "<ACRONYM_DEP>"
    };
  
    private boolean replaceInvalidAcronym;
      
    private int maxTokenLength = StandardAnalyzer.DEFAULT_MAX_TOKEN_LENGTH;
  
    /** Set the max allowed token length.  Any token longer
     *  than this is skipped. */
    public void setMaxTokenLength(int length) {
      this.maxTokenLength = length;
    }
  
    /** @see #setMaxTokenLength */
    public int getMaxTokenLength() {
      return maxTokenLength;
    }
  
    /**
     * Creates a new instance of the {@link ClassicTokenizer}.  Attaches
     * the <code>input</code> to the newly created JFlex scanner.
     *
     * @param input The input reader
     *
     * See http://issues.apache.org/jira/browse/LUCENE-1068
     */
    public ClassicTokenizer(Version matchVersion, Reader input) {
      super();
      init(input, matchVersion);
    }
  
    /**
     * Creates a new ClassicTokenizer with a given {@link AttributeSource}. 
     */
    public ClassicTokenizer(Version matchVersion, AttributeSource source, Reader input) {
      super(source);
      init(input, matchVersion);
    }
  
    /**
     * Creates a new ClassicTokenizer with a given {@link org.apache.lucene.util.AttributeSource.AttributeFactory} 
     */
    public ClassicTokenizer(Version matchVersion, AttributeFactory factory, Reader input) {
      super(factory);
      init(input, matchVersion);
    }
  
    private final void init(Reader input, Version matchVersion) {
      this.scanner = new ClassicTokenizerImpl(input);
  
      if (matchVersion.onOrAfter(Version.LUCENE_24)) {
        replaceInvalidAcronym = true;
      } else {
        replaceInvalidAcronym = false;
      }
      this.input = input;    
    }
  
    // this tokenizer generates three attributes:
    // term offset, positionIncrement and type
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
    private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
    private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
  
    /*
     * (non-Javadoc)
     *
     * @see org.apache.lucene.analysis.TokenStream#next()
     */
    @Override
    public final boolean incrementToken() throws IOException {
      clearAttributes();
      int posIncr = 1;
  
      while(true) {
        int tokenType = scanner.getNextToken();
  
        if (tokenType == StandardTokenizerInterface.YYEOF) {
          return false;
        }
  
        if (scanner.yylength() <= maxTokenLength) {
          posIncrAtt.setPositionIncrement(posIncr);
          scanner.getText(termAtt);
          final int start = scanner.yychar();
          offsetAtt.setOffset(correctOffset(start), correctOffset(start+termAtt.length()));
          // This 'if' should be removed in the next release. For now, it converts
          // invalid acronyms to HOST. When removed, only the 'else' part should
          // remain.
          if (tokenType == ClassicTokenizer.ACRONYM_DEP) {
            if (replaceInvalidAcronym) {
              typeAtt.setType(ClassicTokenizer.TOKEN_TYPES[ClassicTokenizer.HOST]);
              termAtt.setLength(termAtt.length() - 1); // remove extra '.'
            } else {
              typeAtt.setType(ClassicTokenizer.TOKEN_TYPES[ClassicTokenizer.ACRONYM]);
            }
          } else {
            typeAtt.setType(ClassicTokenizer.TOKEN_TYPES[tokenType]);
          }
          return true;
        } else
          // When we skip a too-long term, we still increment the
          // position increment
          posIncr++;
      }
    }
    
    @Override
    public final void end() {
      // set final offset
      int finalOffset = correctOffset(scanner.yychar() + scanner.yylength());
      offsetAtt.setOffset(finalOffset, finalOffset);
    }
  
    @Override
    public void reset(Reader reader) throws IOException {
      super.reset(reader);
      scanner.yyreset(reader);
    }
  
    /**
     * Prior to https://issues.apache.org/jira/browse/LUCENE-1068, ClassicTokenizer mischaracterized as acronyms tokens like www.abc.com
     * when they should have been labeled as hosts instead.
     * @return true if ClassicTokenizer now returns these tokens as Hosts, otherwise false
     *
     * @deprecated Remove in 3.X and make true the only valid value
     */
    @Deprecated
    public boolean isReplaceInvalidAcronym() {
      return replaceInvalidAcronym;
    }
  
    /**
     *
     * @param replaceInvalidAcronym Set to true to replace mischaracterized acronyms as HOST.
     * @deprecated Remove in 3.X and make true the only valid value
     *
     * See https://issues.apache.org/jira/browse/LUCENE-1068
     */
    @Deprecated
    public void setReplaceInvalidAcronym(boolean replaceInvalidAcronym) {
      this.replaceInvalidAcronym = replaceInvalidAcronym;
    }
  }
  