com.smartlogic.tools.LabelForUriManglator Maven / Gradle / Ivy

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package com.smartlogic.tools;

import org.apache.commons.lang3.text.WordUtils;
import org.apache.jena.ext.com.google.common.base.CharMatcher;
import org.apache.jena.ext.com.google.common.base.Strings;
import org.apache.jena.ext.com.google.common.collect.ImmutableMap;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.text.Normalizer;
import java.util.regex.Pattern;

/**
 * Utilities for converting labels to part of prefLabel and altLabel URIs.
 */
public class LabelForUriManglator {

  private static final CharMatcher SPECIAL_ASCII_MATCHER = CharMatcher.ascii()
      .and(CharMatcher.javaLetterOrDigit().negate()).and(CharMatcher.noneOf("._ -"));

  public static String mangle(String label) {
    label = simplify(label);
    label = stripSpecialAsciiCharacters(label);
    label = toCamelCase(label);
    label = applyEndodingWithStripingOfPercents(label);
    label = stripRepeatedHyphens(label);
    label = fixCornerCasesForJena(label);
    return label;
  }

  private static String stripSpecialAsciiCharacters(String label) {
    return SPECIAL_ASCII_MATCHER.replaceFrom(label, "-");
  }

  private static String toCamelCase(String label) {
    if (label.length() >= 1) {
      String first = label.substring(0, 1);
      label = WordUtils.capitalize(label);
      label = first + label.substring(1);
      return label.replaceAll(" ", "");
    } else {
      return label;
    }
  }

  private static String applyEndodingWithStripingOfPercents(String label) {
    label = urlEncode(label);
    return label.replace("%", "");
  }

  private static String stripRepeatedHyphens(String label) {
    return label.replaceAll("[-]+", "-");
  }

  /**
   *    * 1. leading '-' is prefixed by '_' because of URI compatibility issues
   * 2. empty labels is converted to '_'
   * 
   */
  private static String fixCornerCasesForJena(String label) {
    if (Strings.isNullOrEmpty(label)) {
      return "_";
    }
    if (label.startsWith("-")) {
      return "_" + label.substring(1);
    }
    return label;
  }

  private static String urlEncode(String label) {
    try {
      return URLEncoder.encode(label, StandardCharsets.UTF_8.name());
    } catch (UnsupportedEncodingException uee) {
      throw new RuntimeException("Unsupported encoding.", uee);
    }
  }

  private static final ImmutableMap NONDIACRITICS =
      ImmutableMap.builder()

          // Replace non-diacritics as their equivalent characters
          .put("\u0141", "l") // BiaLystock
          .put("\u0142", "l") // Bialystock
          .put("ß", "ss").put("æ", "ae").put("ø", "o").put("©", "c").put("\u00D0", "d")
          // All Ð ð
          // from
          // http://de.wikipedia.org/wiki/%C3%90
          .put("\u00F0", "d").put("\u0110", "d").put("\u0111", "d").put("\u0189", "d")
          .put("\u0256", "d").put("\u00DE", "th") // thorn Þ
          .put("\u00FE", "th") // thorn þ
          .build();

  /*
   * Special regular expression character ranges relevant for simplification -> see
   * http://docstore.mik.ua/orelly/perl/prog3/ch05_04.htm InCombiningDiacriticalMarks: special marks
   * that are part of "normal" ä, ö, î etc.. IsSk: Symbol, Modifier see
   * http://www.fileformat.info/info/unicode/category/Sk/list.htm IsLm: Letter, Modifier see
   * http://www.fileformat.info/info/unicode/category/Lm/list.htm
   */
  private static final Pattern DIACRITICS_AND_FRIENDS =
      Pattern.compile("[\\p{InCombiningDiacriticalMarks}\\p{IsLm}\\p{IsSk}]+");

  public static String simplify(String str) {
    str = stripDiacritics(str);
    return stripNonDiacritics(str);
  }

  private static String stripNonDiacritics(String str) {
    StringBuffer ret = new StringBuffer();
    for (int i = 0; i < str.length(); i++) {
      String source = str.substring(i, i + 1);
      String replace = NONDIACRITICS.get(source);
      if (replace == null) {
        ret.append(source);
      } else {
        ret.append(replace);
      }
    }
    return ret.toString();
  }

  private static String stripDiacritics(String str) {
    str = Normalizer.normalize(str, Normalizer.Form.NFD);
    return DIACRITICS_AND_FRIENDS.matcher(str).replaceAll("");
  }

}