code: package zemberek.ner;
  
  import com.google.common.base.Splitter;
  import java.io.IOException;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Random;
  import java.util.Set;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import zemberek.core.collections.Histogram;
  import zemberek.core.logging.Log;
  import zemberek.core.text.Regexps;
  import zemberek.core.text.TextIO;
  import zemberek.core.text.TextUtil;
  import zemberek.core.turkish.Turkish;
  import zemberek.tokenization.TurkishTokenizer;
  import zemberek.tokenization.Token;
  import zemberek.tokenization.Token.Type;
  
  public class NerDataSet {
  
    public static final String OUT_TOKEN_TYPE = "OUT";
    private static Pattern enamexNePattern = Pattern.compile(
        "((<b_enamex TYPE=\")(?<TYPE>.+?)(\">)(?<CONTENT>.+?)(<e_enamex>))",
        Pattern.CASE_INSENSITIVE);
    private static Pattern enamexNeSplitPattern = Pattern.compile(
        "((<b_enamex TYPE=\")(?<TYPE>.+?)(\">)(?<CONTENT>.+?)(<e_enamex>))|([^ ]+)",
        Pattern.CASE_INSENSITIVE);
    private static Pattern bracketNePattern = Pattern.compile(
        "((\\[)(?<TYPE>[^ ]+)( )(?<CONTENT>.+?)(]))", Pattern.CASE_INSENSITIVE);
    private static Pattern bracketNeSplitPattern = Pattern.compile(
        "((\\[)(?<TYPE>[^ ]+)( )(?<CONTENT>.+?)(]))|([^ ]+)", Pattern.CASE_INSENSITIVE);
    private static Pattern openNlpNePattern = Pattern.compile(
        "((<START:)(?<TYPE>.+?)(>)(?<CONTENT>.+?)(<END>))", Pattern.CASE_INSENSITIVE);
    private static Pattern openNlpNeSplitPattern = Pattern.compile(
        "((<START:)(?<TYPE>.+?)(>)(?<CONTENT>.+?)(<END>))|([^ ]+)", Pattern.CASE_INSENSITIVE);
  
  
    Set<String> types = new HashSet<>();
    Set<String> typeIds = new HashSet<>();
    List<NerSentence> sentences;
  
    public NerDataSet(List<NerSentence> sentences) {
      this.sentences = sentences;
  
      for (NerSentence sentence : sentences) {
        for (NerToken token : sentence.tokens) {
          types.add(token.type);
          typeIds.add(token.tokenId);
        }
      }
    }
  
    public List<NerSentence> getSentences() {
      return sentences;
    }
  
    public enum AnnotationStyle {
      ENAMEX,
      BRACKET,
      OPEN_NLP
    }
  
    static Random rnd = new Random(0xcafe);
  
    public void shuffle() {
      Collections.shuffle(sentences, rnd);
    }
  
    public static NerDataSet load(Path path, AnnotationStyle style) throws IOException {
      switch (style) {
        case BRACKET:
          return loadBracketStyle(path);
        case ENAMEX:
          return loadEnamexStyle(path);
        case OPEN_NLP:
          return loadOpenNlpStyle(path);
      }
      throw new IOException(String.format("Cannot load data from %s with style %s", path, style));
    }
  
    static NerDataSet loadBracketStyle(Path path) throws IOException {
      return loadDataSet(path, bracketNePattern, bracketNeSplitPattern);
    }
  
  
    static NerDataSet loadEnamexStyle(Path path) throws IOException {
      return loadDataSet(path, enamexNePattern, enamexNeSplitPattern);
    }
  
    static NerDataSet loadOpenNlpStyle(Path path) throws IOException {
      return loadDataSet(path, openNlpNePattern, openNlpNeSplitPattern);
    }
  
    public static String normalizeForNer(String input) {
      input = input.toLowerCase(Turkish.LOCALE);
      List<String> result = new ArrayList<>();
      for (Token t : TurkishTokenizer.DEFAULT.tokenize(input)) {
        String s = t.getText();
        if (t.getType() == Token.Type.Date || t.getType() == Type.Number
            || t.getType() == Token.Type.Time) {
          s = "*" + s.replaceAll("[0-9]", "D") + "*";
        }
        result.add(s);
      }
      return String.join("", result);
    }
  
    static NerDataSet loadDataSet(
        Path path,
        Pattern nePattern,
        Pattern splitPattern) throws IOException {
  
      Log.info("Extracting data from %s", path);
  
      List<String> lines = TextIO.loadLines(path);
  
      List<NerSentence> nerSentences = new ArrayList<>(lines.size());
      for (String line : lines) {
        line = TextUtil.normalizeApostrophes(line);
        line = TextUtil.normalizeQuotesHyphens(line);
        line = TextUtil.normalizeSpacesAndSoftHyphens(line);
  
        if (line.trim().length() < 2) {
          continue;
        }
        List<String> tokens = Regexps.allMatches(splitPattern, line);
        List<NerToken> nerTokens = new ArrayList<>(tokens.size());
        int index = 0;
        for (String token : tokens) {
          //combine apostrophe suffix to previous word.
          if (index > 0 && token.startsWith("'") && !token.endsWith("'")) {
            nerTokens.get(index - 1).word = nerTokens.get(index - 1).word + token;
            nerTokens.get(index - 1).normalized = nerTokens.get(index - 1).normalized + token;
            continue;
          }
  
          // not a ner word.
          if (!nePattern.matcher(token).matches()) {
            nerTokens.add(new NerToken(index, token, normalizeForNer(token), OUT_TOKEN_TYPE,
                NePosition.OUTSIDE));
            index++;
            continue;
          }
          Matcher matcher = nePattern.matcher(token);
          if (matcher.find()) {
            String type = matcher.group("TYPE");
            String content = matcher.group("CONTENT");
            List<String> neWords = Splitter.on(" ").trimResults().omitEmptyStrings()
                .splitToList(content);
            for (int i = 0; i < neWords.size(); i++) {
              String s = neWords.get(i);
              NePosition position;
              if (neWords.size() == 1) {
                position = NePosition.UNIT;
              } else if (i == 0) {
                position = NePosition.BEGIN;
              } else if (i == neWords.size() - 1) {
                position = NePosition.LAST;
              } else {
                position = NePosition.INSIDE;
              }
              nerTokens.add(new NerToken(index, s, normalizeForNer(s), type, position));
              index++;
            }
          }
        }
        nerSentences.add(new NerSentence(line, nerTokens));
      }
      return new NerDataSet(nerSentences);
    }
  
    public void addSet(NerDataSet set) {
      this.sentences.addAll(set.sentences);
      types.addAll(set.types);
      typeIds.addAll(set.typeIds);
    }
  
    public NerDataSet getSubSet(int from, int to) {
      return new NerDataSet(new ArrayList<>(sentences.subList(from, to)));
    }
  
    /**
     * prints information about the data set.
     */
    public String info() {
      return new Info(this).log();
    }
  
    public static class Info {
  
      int numberOfSentences;
      Set<String> types;
      Histogram<String> typeHistogram = new Histogram<>();
      Histogram<String> tokenHistogram = new Histogram<>();
      int numberOfTokens;
  
      public Info(NerDataSet set) {
        this.types = set.types;
        this.numberOfSentences = set.sentences.size();
        for (NerSentence sentence : set.sentences) {
          numberOfTokens += sentence.tokens.size();
          for (NerToken token : sentence.tokens) {
            tokenHistogram.add(token.type);
            if (token.position == NePosition.OUTSIDE ||
                token.position == NePosition.BEGIN ||
                token.position == NePosition.UNIT) {
              typeHistogram.add(token.type);
            }
          }
        }
      }
  
      public String log() {
        List<String> res = new ArrayList<>();
        res.add(String.format("Number of sentences      = %d", numberOfSentences));
        res.add(String.format("Number of tokens         = %d", numberOfTokens));
        for (String type : typeHistogram.getSortedList()) {
          res.add(String.format(Locale.ENGLISH,"Type = %s (Count = %d, Token Count = %d Av. Token = %.2f )",
              type,
              typeHistogram.getCount(type),
              tokenHistogram.getCount(type),
              tokenHistogram.getCount(type) * 1f / typeHistogram.getCount(type)));
        }
        return String.join("\n", res);
      }
  
    }
  }
  