(Errors with my code)

Assignment:

Purpose: To model a DFA (Deterministic Finite Automaton) and use it to accept strings of the associated language. Input: The program should take the DFA description from a text file that is specified as a command line parameter. If this parameter is missing, the user should be prompted for the data file. Strings to be tested for inclusion in the language should be entered interactively by the user. Output: For each string being tested, the program should indicate whether or not the string is accepted. DFA input format: line 1: alphabet - eg. {0,1} line 2: states - eg. {a,b,c,d,e} line 3: start state - eg. a line 4: accept states - eg. {d,e} lines 5-: transition fn - eg. (a,0)->b (a,1)->c etc. Notes: Assume no spaces in input. Alphabet must at least allow {0,1}. Please feel free to expand this. States must at least allow lower case letters, but you are welcome to expand this to numerals and upper case letters. Transition functions may appear in any order in the input text file. End of the input file indicates the end of transition functions. Name the source code file Dfa.java. You are encouraged to team up with other students in class for the project with no more than 5 students per team. Full participation of each member in a team is expected. When your team has finished the project, you will upload (submit) it to the Project dropbox folder in folio. I remind you that if you do not submit the project before the due date, you will not be able to submit it. 1. Complete the assignment including the following contents: 1) the source code file, 2) a sample DFA text file, 3) screenshots of your result, 4) a README file to discuss the details of your program. 2. Return to the dropbox folder for this project. Spring 2018 Instructor: Dr. Lixin Li 3. Look for the Add a File button in the Submit Files area. 4. Browse for the project files that you have on your computer, and select them so that they upload to the assignment area. 5. Each group only need to submit one set of files. 6. Click Submit.

DFA-Test.txt

{0,1} {a,b,c,d} a {d} (a,0)->b (a,1)->a (b,0)->c (b,1)->a (c,0)->c (c,1)->d (d,0)->d (d,1)->d

DFA.Java

package Theory2;

import java.awt.Component;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.HashSet;

import java.util.LinkedList;

import java.util.Optional;

import java.util.Queue;

import java.util.Set;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import java.util.stream.Collectors;

import javax.swing.JOptionPane;

public class DFA {

private static Set alphabet = new HashSet();

private static Set states = new HashSet();

private static CurrentState startingState;

private static Set transitionFunction = new HashSet();

public static void main(String[] args) {

String fileName, input = null;

if (args.length != 0) {

fileName = args[0];

}

else {

Component frame = null;

fileName = JOptionPane.showInputDialog(

frame,

"Gimme dat juicy file name with the fat extension and full motha flippin path ",

"Requested File",

JOptionPane.PLAIN_MESSAGE);

}

File file = new File(fileName);

try {

BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));

String line = null;

// Read first line of alphabet

line = br.readLine();

line = line.substring(1, line.length()-1);

String[] alphabet = line.split(",");

// Add alphabet to set

for (String s: alphabet) {

addToAlphabet(Integer.parseInt(s));;

}

// Read second line of states

line = br.readLine();

line = line.substring(1, line.length()-1);

String[] stateNames = line.split(",");

// Add states to set

for (String s: stateNames) {

CurrentState state = new CurrentState(s.charAt(0));

state.setAcceptState(true);

addToStates(state);

}

// Read third line of start state

line = br.readLine();

startingState = getStatebyName(line.charAt(0));

// Read fourth line of accept states

line = br.readLine();

line = line.substring(1, line.length()-1);

String[] acceptStateLetters = line.split(",");

// Set those states to final states also

for (String s: acceptStateLetters) {

char name = s.charAt(0);

states.stream().filter(state -> state.getName() == name).forEach(state -> makeFinalState(state));

}

//Read fifth line of transition functions

line = br.readLine();

String pattern = "\\((\\w),(\\w)\\)(\\W*)(\\w)";

Pattern r = Pattern.compile(pattern);

Matcher m = r.matcher(line);

while (m.find()) {

Transition transition = new Transition(getStatebyName(m.group(1).charAt(0)), Integer.parseInt(m.group(2)), getStatebyName(m.group(4).charAt(0)));

addTransition(transition);

}

br.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

while (true) {

Component frame = null;

input = JOptionPane.showInputDialog(

frame ,

"Enter string of ints to test the consutrcted DFA NO NULLS ALLOWED!",

"Test the DFA",

JOptionPane.PLAIN_MESSAGE);

if (input == "exit"){

System.exit(0);

break;

}

else {

String[] inputArray = input.split("");

LinkedList inputList = new LinkedList<>(); //Linked lists are dangerous

for (String s: inputArray) {

if (!isInteger(s)) {

JOptionPane.showMessageDialog(frame, input + " Rejected for not being a number between 0 and 1");

break;

}

inputList.add(Integer.parseInt(s));

}

if (calculateFinalState(startingState, inputList)) {

JOptionPane.showMessageDialog(frame, " Accepted in what world? Bro you have no friends...");

continue;

}

else {

JOptionPane.showMessageDialog(frame, input + " Rejected... Just like all the women you asked out");

continue;

}

}

}

}

private static boolean isInteger(String s) {

char c = s.charAt(0);

return (c >= 48 && c <= 57);

}

private static void makeFinalState(CurrentState state) {

state.setFinalState(true);

}

private static CurrentState getStatebyName(char name) {

return states.stream().filter(s -> s.getName() == name).findFirst().get();

}

public static void addToAlphabet(Integer letter) {

alphabet.add(letter);

}

public static void removeFromAlphabet(Integer letter){

alphabet.remove(letter);

}

public static void addToStates(CurrentState state){

states.add(state);

}

public static void removeToState(CurrentState state){

states.remove(state);

}

public static void removeTransition(Transition transition){

transitionFunction.remove(transition);

}

public static void addTransition(Transition transition) throws IllegalArgumentException{

// no 2 outputs for same input+letter

if(transitionFunction.stream().noneMatch(t -> t.getInputState().equals(transition.getInputState()) && t.getSymbol() == transition.getSymbol())){

transitionFunction.add(transition);

} else {

throw new IllegalArgumentException();

}

}

public Set getAcceptStates(){

return states.stream().filter(s -> s.isAcceptState()).collect(Collectors.toSet());

}

public static boolean calculateFinalState(CurrentState state, Queue letter) {

if(letter.isEmpty() && state.isFinalState()){

return true;

}

if(!alphabet.contains(letter.peek())){

return false;

}

Optional nextState = getNextState(state, letter.poll());

if(nextState.isPresent()){

return calculateFinalState(nextState.get(), letter);

}

return false;

}

private static Optional getNextState(CurrentState state, Integer alphabet){

return transitionFunction.stream().filter(t -> t.getInputState().equals(state) && t.getSymbol() == alphabet).map(t -> t.getOutputState()).findFirst();

}

}

CurrentState.java

package Theory2;

public class CurrentState {

private boolean finalState = false;

private boolean acceptState = false;

private char name;

//not gonna lie most of this code was generated thanks Eclipse!

public CurrentState(char name) {

this.name = name;

}

public char getName() {

return name;

}

public void setName(char name) {

this.name = name;

}

public boolean isFinalState() {

return finalState;

}

public void setFinalState(boolean finalState) {

this.finalState = finalState;

}

public boolean isAcceptState() {

return acceptState;

}

public void setAcceptState(boolean acceptState) {

this.acceptState = acceptState;

}

}

Transition.java

package Theory2;

public class Transition {

CurrentState input;

Integer symbol;

CurrentState output;

//not gonna lie most of this code was generated too thanks Eclipse!

public Transition(CurrentState input, Integer symbol, CurrentState output){

this.input = input;

this.symbol = symbol;

this.output = output;

}

public CurrentState getInputState() {

return input;

}

public Integer getSymbol() {

return symbol;

}

public CurrentState getOutputState() {

return output;

}

}