Efficently Replacement of all unsupported chars in

Question

Possible Duplicate:
Converting Symbols, Accent Letters to English Alphabet

I need to replace all accented characters, such as

"à", "é", "ì", "ò", "ù"

with

"a'", "e'", "i'", "o'", "u'"...

because of an issue with reloading nested strings with accented characters after they've been saved.

Is there a way to do this without using different string replacement for all chars?

For example, I would prefer to avoid doing

text  = text.replace("a", "a'");
text2 = text.replace("è", "e'");
text3 = text2.replace("ì", "i'");
text4 = text3.replace("ò", "o'");
text5 = text4.replace("ù", "u'");

etc.

Answer 1

I tried this from this post it seems to work.

String str= Normalizer.normalize(str, Normalizer.Form.NFD);
str= str.replaceAll("\\p{InCombiningDiacriticalMarks}+", "'");

Edit: But replacing the Combining diacritical marks, has a side effect that you cannot distinguish between À Á Â

Answer 2

After reading the comments in the main approach, I think a better option would be fix the problem - which is encoding related? - and not try to cover up the symptoms.

Also, this still requires a manual explicit mapping, which might make it less ideal than nandeesh's answer with a regular expression unicode character class.

---

Here is a skeleton for code to perform the mapping. It is slightly more complicated than a char-char.

This code tries to avoid extra Strings. It may or not be "more efficient". Try it with the real data/usage. YMMV.

String mapAccentChar (char ch) {
    switch (ch) {
        case 'à': return "a'";
        // etc
    }
    return null;
}

String mapAccents (String input) {
  StringBuilder sb = new StringBuilder();
  int l = input.length();
  for (int i = 0; i < l; i++) {
    char ch = input.charAt(i);
    String mapped = mapAccentChar(ch);
    if (mapped != null) {
      sb.append(mapped);
    } else {
      sb.append(ch);
  }
  return sb.toString();
}

Answer 3

If you don't mind adding commons-lang as a dependency, try StringUtils.replaceEach I believe the following perform the same task:

import org.apache.commons.lang.StringUtils;

public class ReplaceEachTest
{
   public static void main(String [] args)
   {
      String text = "àéìòùàéìòù";
      String [] searchList = {"à", "é", "ì", "ò", "ù"};
      String [] replaceList = {"a'", "e'", "i'", "o'", "u'"};
      String newtext = StringUtils.replaceEach(text, searchList, replaceList);
      System.out.println(newtext);
   }
}

This example prints a'e'i'o'u'a'e'i'o'u' However in general I agree that since you are creating a custom character translation, you will need a solution where your explicitly specify the replacement for each character of interest.

My previous answer using replaceChars is no good because it only handles one-to-one character replacement.

Answer 4

Since there is no strict correlation between ASCII value of a char and its accented version, your replacement seems to me the most straightforward way.