private static void searchAndAddStates(
String currStateString,
List<String> statesToBeParsed,
HashMap<String, State> stringToStateMap,
HashMap<String, String[]> statesTransitions,
String[] alphabet,
Set<String> finalStates,
MapBasedDFA dfa) {
if (!statesToBeParsed.contains(currStateString)) return;
State currState = stringToStateMap.get(currStateString);
statesToBeParsed.remove(currStateString);
for (int i = 0; i < statesTransitions.get(currStateString).length; i++) {
String nextStateString = statesTransitions.get(currStateString)[i];
Character transitionLetter = alphabet[i].charAt(0);
State nextState;
if (stringToStateMap.containsKey(nextStateString)) {
nextState = stringToStateMap.get(nextStateString);
} else {
nextState = new State();
stringToStateMap.put(nextStateString, nextState);
}
if (finalStates.contains(nextStateString)) nextState.setFinal(true);
dfa.addTransition(currState, transitionLetter, nextState);
searchAndAddStates(
nextStateString,
statesToBeParsed,
stringToStateMap,
statesTransitions,
alphabet,
finalStates,
dfa);
}
}
private static void writeDFA(DFA dfa, Writer out) throws IOException {
Character[] alphabet = dfa.alphabet().toArray(new Character[0]);
State[] states = dfa.allStates().toArray(new State[0]);
out.write("Start: ");
out.write(dfa.startState().toString());
out.write("\n");
out.write("Final: ");
for (State state : dfa.finalStates()) {
out.write("\t");
out.write(state.toString());
}
out.write("\n");
out.write("-");
for (Character character : alphabet) {
out.write("\t");
out.write(character);
}
out.write("\n");
for (State currState : states) {
out.write(currState.toString());
// out.write("\t");
for (Character charater : alphabet) {
out.write("\t");
out.write(dfa.transition(currState, charater).toString());
}
out.write("\n");
}
out.write("--Tokens\n");
for (State currState : states) {
Stack<Token> tokens = currState.getTokens();
out.write(currState.toString());
while (!tokens.isEmpty()) {
out.write("\t");
out.write(tokens.pop().toString());
}
out.write("\n");
}
out.flush();
}
/**
* Performs the import of a DFA from a file.
*
* @param file Origination file.
* @return Loaded DFA.
*/
public static DFA importDFA(File file) {
try {
Scanner scan = new Scanner(file);
HashMap<String, State> stringToStateMap = new HashMap<String, State>();
HashMap<String, String[]> statesTransitions = new HashMap<String, String[]>();
List<String> statesToBeParsed = new LinkedList<String>();
State.resetCount();
String startStateString = scan.nextLine();
if (!startStateString.startsWith("Start:")) {
System.out.println("Error: Invalid DFA format");
System.exit(1);
}
startStateString = startStateString.split(" ")[1];
String finalStatesUnparsed = scan.nextLine();
int tabIndex = finalStatesUnparsed.indexOf(" ");
String[] finalStates = finalStatesUnparsed.substring(tabIndex + 1).split("\t");
HashSet<String> finalStateSet = new HashSet<String>();
finalStateSet.addAll(Arrays.asList(finalStates));
String alphabetUnparsed = scan.nextLine();
tabIndex = alphabetUnparsed.indexOf("\t");
String[] alphabet = alphabetUnparsed.substring(tabIndex + 1).split("\t");
int stateCount = 0;
String currLine = scan.nextLine();
while (!currLine.equalsIgnoreCase("--Tokens")) {
String stateTransitions = currLine;
tabIndex = stateTransitions.indexOf("\t");
String state = stateTransitions.substring(0, tabIndex);
String transitions = stateTransitions.substring(tabIndex + 1);
statesTransitions.put(state, transitions.split("\t"));
statesToBeParsed.add(state);
stateCount++;
currLine = scan.nextLine();
}
HashMap<String, String[]> tokenMap = new HashMap<String, String[]>();
while (scan.hasNext()) {
String stateTokens = scan.nextLine();
tabIndex = stateTokens.indexOf("\t");
if (tabIndex == -1) {
tokenMap.put(stateTokens, new String[0]);
continue;
}
String state = stateTokens.substring(0, tabIndex);
String tokenString = stateTokens.substring(tabIndex + 1);
String[] tokens = tokenString.split("\t");
tokenMap.put(state, tokens);
}
State startState = new State();
stringToStateMap.put(startStateString, startState);
MapBasedDFA returnDFA = new MapBasedDFA(startState);
searchAndAddStates(
startStateString,
statesToBeParsed,
stringToStateMap,
statesTransitions,
alphabet,
finalStateSet,
returnDFA);
for (String currStateString : tokenMap.keySet()) {
State currState = stringToStateMap.get(currStateString);
Stack<Token> tokens = new Stack<Token>();
for (int i = tokenMap.get(currStateString).length - 1; i >= 0; i--) {
String tokenString = tokenMap.get(currStateString)[i];
tokenString = tokenString.substring(1, tokenString.length() - 1);
if (tokenString.charAt(0) == '/') {
tokens.push(new Token(tokenString.substring(1), false));
} else {
tokens.push(new Token(tokenString, true));
}
}
currState.setTokens(tokens);
}
return returnDFA;
} catch (IOException ex) {
System.out.println("Error writing DFA to: " + file.toString());
return null;
}
}
