001/* Copyright (C) 2013 TU Dortmund 002 * This file is part of AutomataLib, http://www.automatalib.net/. 003 * 004 * AutomataLib is free software; you can redistribute it and/or 005 * modify it under the terms of the GNU Lesser General Public 006 * License version 3.0 as published by the Free Software Foundation. 007 * 008 * AutomataLib is distributed in the hope that it will be useful, 009 * but WITHOUT ANY WARRANTY; without even the implied warranty of 010 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 011 * Lesser General Public License for more details. 012 * 013 * You should have received a copy of the GNU Lesser General Public 014 * License along with AutomataLib; if not, see 015 * http://www.gnu.de/documents/lgpl.en.html. 016 */ 017package net.automatalib.words; 018 019 020/** 021 * {@link Alphabet} class that supports adding new symbols. 022 * 023 * @param <I> symbol class. 024 * 025 * @author Malte Isberner <malte.isberner@gmail.com> 026 */ 027public interface GrowingAlphabet<I> extends Alphabet<I> { 028 029 /** 030 * Adds a new symbol to the alphabet. Some alphabets may prevent 031 * symbols from being added twice. In this case, the original alphabet 032 * remains unchanged, but this is not considered an error. 033 * 034 * @return the index of the symbol in the alphabet, after adding it. 035 */ 036 public abstract int addSymbol(I a); 037 038}