code: static Set<String> parseParametersToCheck(final String initParamValue) {
  
          final Set<String> parameterNames = new HashSet<String>();
  
          if (null == initParamValue) {
              return parameterNames;
          }
  
          final String[] tokens = initParamValue.split("\\s+");
  
          if (0 == tokens.length) {
              throw new IllegalArgumentException(
                      "["
                              + initParamValue
                              + "] had no tokens but should have had at least one token.");
          }
  
          if (1 == tokens.length && "*".equals(tokens[0])) {
              return parameterNames;
          }
  
          for (final String parameterName : tokens) {
  
              if ("*".equals(parameterName)) {
                  throw new IllegalArgumentException(
                          "Star token encountered among other tokens in parsing ["
                                  + initParamValue
                                  + "]");
              }
  
              parameterNames.add(parameterName);
          }
  
          return parameterNames;
      }
docs: Parse the whitespace delimited String of parameters to check.
  
  <p>If the String is null, return the empty set. If the whitespace delimited String contains
  no tokens, throw IllegalArgumentException. If the sole token is an asterisk, return the empty
  set. If the asterisk token is encountered among other tokens, throw IllegalArgumentException.
  
  <p>This method returning an empty Set has the special meaning of "check all parameters".
  
  <p>This is a stateless static method.
  
  <p>This method is an implementation detail and is not exposed API. This method is only
  non-private to allow JUnit testing.
  
  @param initParamValue null, or a non-blank whitespace delimited list of parameters to check
  @return a Set of String names of parameters to check, or an empty set representing
  check-them-all.
  @throws IllegalArgumentException when the init param value is out of spec