code: public final boolean cleanAllowed(final File file) {
          if (cleanExclude == null) {
              return true;
          }
          if (cleanExcludeFilter == null) {
              cleanExcludeFilter = new RegexFileFilter(cleanExclude);
          }
          return !cleanExcludeFilter.accept(file);
      }
docs: Checks if a file should be excluded from cleaning.
  
  @param file
  File to check against the exlcude condition.
  
  @return TRUE if the file can be cleaned.