EnsureEncoding main part

EnsureEncoding_part.java

/**
   * will try to convert the given chars to a valid string.
   * will check for every valid conversion if the given {@link ContentCheck} is valid, if not
   * it will continue with the next encoding
   * 
   * @param chars
   *          characters in an unknown charset
   * @param check
   *          this instance will be called for every valid conversion
   * @return the chars converted to a String decoded by the first matching {@link Charset}
   * @throws Exception
   *           if converting the chars to a String was not possible
   */
  public String decode(byte[] chars, ContentCheck check) throws Exception {
    for (Charset encodingToTry : encodingsToTry) {
      try {
        String content = decode(chars, encodingToTry);

        if (check.isValidContent(content)) {
          return content;
        }
      } catch (CharacterCodingException e) {
        // try with next encoding
      }
    }
    throw new IllegalStateException("was not able to encode string using these encodings"
        + Arrays.toString(encodingsToTry));
  }

  protected String decode(byte[] chars, Charset encodingToTry) throws CharacterCodingException {
    CharsetDecoder decoder = encodingToTry.newDecoder().onMalformedInput(CodingErrorAction.REPORT);

    ByteBuffer byteBuffer = ByteBuffer.wrap(chars);
    CharBuffer decoded = decoder.decode(byteBuffer);

    return decoded.toString();
  }