/** Returns a new (deterministic) automaton that accepts only the empty string. */
 public static DefaultAutomaton makeEmptyString() {
   DefaultAutomaton a = new DefaultAutomaton();
   a.singleton = "";
   a.deterministic = true;
   return a;
 }
 /** Returns a new (deterministic) automaton that accepts a single character of the given value. */
 public static DefaultAutomaton makeChar(char c) {
   DefaultAutomaton a = new DefaultAutomaton();
   a.singleton = Character.toString(c);
   a.deterministic = true;
   return a;
 }
 /** Returns a new (deterministic) automaton that accepts the single given string. */
 public static DefaultAutomaton makeString(String s) {
   DefaultAutomaton a = new DefaultAutomaton();
   a.singleton = s;
   a.deterministic = true;
   return a;
 }