code: /**
   * boilerpipe
   *
   * Copyright (c) 2009, 2014 Christian Kohlschütter
   *
   * The author 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 com.kohlschutter.boilerpipe.filters.english;
  
  import com.kohlschutter.boilerpipe.BoilerpipeFilter;
  import com.kohlschutter.boilerpipe.BoilerpipeProcessingException;
  import com.kohlschutter.boilerpipe.document.TextBlock;
  import com.kohlschutter.boilerpipe.document.TextDocument;
  import com.kohlschutter.boilerpipe.labels.DefaultLabels;
  
  /**
   * Finds blocks which are potentially indicating the end of an article text and marks them with
   * {@link DefaultLabels#INDICATES_END_OF_TEXT}. This can be used in conjunction with a downstream
   * {@link IgnoreBlocksAfterContentFilter}.
   * 
   * @see IgnoreBlocksAfterContentFilter
   */
  public class TerminatingBlocksFinder implements BoilerpipeFilter {
    public static final TerminatingBlocksFinder INSTANCE = new TerminatingBlocksFinder();
  
    /**
     * Returns the singleton instance for TerminatingBlocksFinder.
     */
    public static TerminatingBlocksFinder getInstance() {
      return INSTANCE;
    }
  
    // public static long timeSpent = 0;
  
    public boolean process(TextDocument doc) throws BoilerpipeProcessingException {
      boolean changes = false;
  
      // long t = System.currentTimeMillis();
  
      for (TextBlock tb : doc.getTextBlocks()) {
        final int numWords = tb.getNumWords();
        if (numWords < 15) {
          final String text = tb.getText().trim();
          final int len = text.length();
          if (len >= 8) {
            final String textLC = text.toLowerCase();
            if (textLC.startsWith("comments")
                || startsWithNumber(textLC, len, " comments", " users responded in")
                || textLC.startsWith("© reuters") || textLC.startsWith("please rate this")
                || textLC.startsWith("post a comment") || textLC.contains("what you think...")
                || textLC.contains("add your comment") || textLC.contains("add comment")
                || textLC.contains("reader views") || textLC.contains("have your say")
                || textLC.contains("reader comments") || textLC.contains("rätta artikeln")
                || textLC.equals("thanks for your comments - this feedback is now closed")) {
              tb.addLabel(DefaultLabels.INDICATES_END_OF_TEXT);
              changes = true;
            }
          } else if (tb.getLinkDensity() == 1.0) {
            if (text.equals("Comment")) {
              tb.addLabel(DefaultLabels.INDICATES_END_OF_TEXT);
            }
          }
        }
      }
  
      // timeSpent += System.currentTimeMillis() - t;
  
      return changes;
    }
  
    /**
     * Checks whether the given text t starts with a sequence of digits, followed by one of the given
     * strings.
     * 
     * @param t The text to examine
     * @param len The length of the text to examine
     * @param str Any strings that may follow the digits.
     * @return true if at least one combination matches
     */
    private static boolean startsWithNumber(final String t, final int len, final String... str) {
      int j = 0;
      while (j < len && isDigit(t.charAt(j))) {
        j++;
      }
      if (j != 0) {
        for (String s : str) {
          if (t.startsWith(s, j)) {
            return true;
          }
        }
      }
      return false;
    }
  
    private static boolean isDigit(final char c) {
      return c >= '0' && c <= '9';
    }
  
  }
  