public static String replacePdxRenamePattern(Pattern pattern, String existing,
      String replacement) {
    Matcher matcher = pattern.matcher(existing);
    if (matcher.matches()) {
      int start = matcher.start(1);
      int end = matcher.end(1);
      StringBuilder sb = new StringBuilder();
      if (start > 0) {
        sb.append(existing, 0, start);
      }
      sb.append(replacement);
      if (end < existing.length()) {
        sb.append(existing.substring(end));
      }
      return sb.toString();
    }
    return null;
  }
Destroy a region which has not been created.

@param regName the name of the region to destroy
geode-core/src/main/java/org/apache/geode/internal/cache/DiskStoreImpl.java