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This artifact provides various common utility operations for analyzing and manipulating automata and graphs, such as traversal, minimization and copying.

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/* Copyright (C) 2013 TU Dortmund
 * This file is part of AutomataLib, http://www.automatalib.net/.
 * 
 * AutomataLib is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 3.0 as published by the Free Software Foundation.
 * 
 * AutomataLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with AutomataLib; if not, see
 * http://www.gnu.de/documents/lgpl.en.html.
 */
package net.automatalib.util.ts.traversal;

import java.util.Collection;
import java.util.Iterator;

import net.automatalib.ts.TransitionSystem;

class SimpleDFRecord {

	public final S state;

	private final Iterator inputsIterator;
	private I input;
	private Iterator transitionIterator;

	public SimpleDFRecord(S state, Collection inputs) {
		this.state = state;
		this.inputsIterator = inputs.iterator();
	}

	private void findNext(TransitionSystem ts) {
		if(transitionIterator != null && transitionIterator.hasNext())
			return;
		while(inputsIterator.hasNext()) {
			input = inputsIterator.next();
			Collection transitions = ts.getTransitions(state, input);
			if(!transitions.isEmpty()) {
				transitionIterator = transitions.iterator();
				break;
			}
		}
	}

	public boolean start(TransitionSystem ts) {
		if(transitionIterator != null)
			return false;
		
		findNext(ts);
		return true;
	}

	public boolean hasNextTransition(TransitionSystem ts) {
		if(transitionIterator == null)
			return false;
		if(!transitionIterator.hasNext()) {
			findNext(ts);
		}
		return transitionIterator.hasNext();
	}

	public void advance(TransitionSystem ts) {
		if(transitionIterator.hasNext())
			return;
		findNext(ts);
	}

	public void advanceInput(TransitionSystem ts) {
		transitionIterator = null;
		findNext(ts);
	}

	public I input() {
		return input;
	}

	public T transition() {
		return transitionIterator.next();
	}

}