code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2014 Daniel Naber (http://www.danielnaber.de)
   * 
   * 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;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.ResourceBundle;
  
  import org.apache.commons.lang3.StringUtils;
  import org.languagetool.AnalyzedSentence;
  import org.languagetool.AnalyzedTokenReadings;
  
  /**
   * Checks that there's whitespace between sentences.
   *   
   * @author Daniel Naber
   * @since 2.5
   */
  public class SentenceWhitespaceRule extends TextLevelRule {
  
    public SentenceWhitespaceRule(ResourceBundle messages) {
      super(messages);
      super.setCategory(Categories.TYPOGRAPHY.getCategory(messages));
      setLocQualityIssueType(ITSIssueType.Whitespace);
    }
    
    @Override
    public String getId() {
      return "SENTENCE_WHITESPACE";
    }
  
    @Override
    public String getDescription() {
      return messages.getString("missing_space_between_sentences");
    }
  
    public String getMessage(boolean prevSentenceEndsWithNumber) {
      return messages.getString("addSpaceBetweenSentences");
    }
  
    @Override
    public RuleMatch[] match(List<AnalyzedSentence> sentences) throws IOException {
      boolean isFirstSentence = true;
      boolean prevSentenceEndsWithWhitespace = false;
      boolean prevSentenceEndsWithNumber = false;
      List<RuleMatch> ruleMatches = new ArrayList<>();
      int pos = 0;
      for (AnalyzedSentence sentence : sentences) {
        AnalyzedTokenReadings[] tokens = sentence.getTokens();
        if (isFirstSentence) {
          isFirstSentence = false;
        } else {
          if (!prevSentenceEndsWithWhitespace && tokens.length > 1) {
            String firstToken = tokens[1].getToken();
            RuleMatch ruleMatch = new RuleMatch(this, sentence, pos, pos+firstToken.length(), getMessage(prevSentenceEndsWithNumber));
            ruleMatch.setSuggestedReplacement(" " + firstToken);
            ruleMatches.add(ruleMatch);
          }
        }
        if (tokens.length > 0) {
          String lastToken = tokens[tokens.length-1].getToken();
          prevSentenceEndsWithWhitespace = lastToken.replace('\u00A0',' ').trim().isEmpty() && lastToken.length() == 1;
        }
        if (tokens.length > 1) {
          String prevLastToken = tokens[tokens.length-2].getToken();
          prevSentenceEndsWithNumber = StringUtils.isNumeric(prevLastToken);
        }
        pos += sentence.getCorrectedTextLength();
      }
      return toRuleMatchArray(ruleMatches);
    }
  
    @Override
    public int minToCheckParagraph() {
      return 0;
    }
    
  }
  