code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2010 Marcin Miłkowski (www.languagetool.org)
   * 
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
   * USA
   */
  package org.languagetool.rules.bitext;
  
  import java.io.IOException;
  
  import org.languagetool.AnalyzedSentence;
  import org.languagetool.AnalyzedTokenReadings;
  import org.languagetool.rules.ITSIssueType;
  import org.languagetool.rules.RuleMatch;
  
  /**
   * Checks if the translation has a really different length than the source
   * (smaller than 30% or longer by 250%).
   * 
   * @author Marcin Miłkowski
   */
  public class DifferentLengthRule extends BitextRule {
  
    private static final int MAX_SKEW = 250;
    private static final int MIN_SKEW = 30;
  
    public DifferentLengthRule() {
      setLocQualityIssueType(ITSIssueType.Length);
    }
  
    @Override
    public String getDescription() { 
      return "Check if translation length is similar to source length";
    }
    
    @Override
    public String getId() {
      return "TRANSLATION_LENGTH";
    }
  
    @Override
    public String getMessage() {
      return "Source and target translation lengths are very different";
    }
  
    @Override
    public RuleMatch[] match(AnalyzedSentence sourceText,
        AnalyzedSentence targetText) throws IOException {
     
      if (isLengthDifferent(sourceText.getText(), targetText.getText())) {
        AnalyzedTokenReadings[] tokens = targetText.getTokens();
        int endPos = tokens[tokens.length - 1].getStartPos() + tokens[tokens.length - 1].getToken().length();
        return new RuleMatch[] { new RuleMatch(this, targetText, 0, endPos, getMessage()) };
      }
      return new RuleMatch[0];
    }
    
    private boolean isLengthDifferent(String src, String trg) {
      double skew = ((double) src.length() / (double) trg.length()) * 100.00;
      return skew > MAX_SKEW || skew < MIN_SKEW;
    }
    
  }
  