// THIS PROGRAM WILL ONLY COMPILE WITH JDK 1.8 OR LATER

/////////////////////////////////////////////////////////////////
// SAMPLE SUBCLASS OF FSM3: DFA to recognized regular expression a(a|b)*b 

public class dfa3 extends FSM3<String>  // will cast chars to strings
{
    String instring; // input string
    int ci; // current char position in instring
    public dfa3(String x)
	{
	    instring = x;
	    ci = 0; // current character in instring.
	    states = 4;  // state 0 is always start state
	    maxinputs = 2;  // input restricted to 'a', 'b'
	    setHash();
	    setStateTable();
	}
    protected boolean acceptState(int s) { return s==2; } // 2 is accept state
    protected void setHash()
    {
	Hash = new JHMadaptor<String,Integer>(10);
	Hash.set("a",0);  Hash.set("b",1);
    }
    protected void setStateTable()
    {
	M = new action[states][maxinputs];
	int a = Hash.get("a"), b = Hash.get("b");
	M[0][a] = new action() { public int act() { return 1; } };
	// in Java 1.8, above same as M[0][a] = () -> 1;
	M[0][b] = () -> { return 3; };
	M[1][a] = () -> 1;  // same as { return 1; }
	M[1][b] = () -> 2; 
	M[2][a] = () -> 1;
	M[2][b] = () -> 2;
	for(int i=a;i<=b;i++) M[3][i] = () -> 3;
    }//setStateTable

    protected String nextInput() // gets next available input, null if none
    {
	if (ci > instring.length()-1) return null;
	return ""+instring.charAt(ci++);
    }

    public static void main(String[] argv)
    {
	dfa3 automaton = new dfa3(argv[0]);
	automaton.trace = true; // prints current input and state
	automaton.keeprunning = true;  // process entire input
	automaton.skipbadinput = false; // terminates on invalid input
	boolean result = automaton.run();
	System.out.println(result);
    }

}//dfa3