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A library for incremental automata construction. This artifact contains algorithms for incrementally constructing DFAs (prefix-closed and non-prefix-closed), Mealy machines, and Moore machines from a finite, incrementally growing set of example inputs/outputs.

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/* Copyright (C) 2013 TU Dortmund
 * This file is part of AutomataLib, http://www.automatalib.net/.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.automatalib.incremental.dfa.dag;

import java.util.Arrays;

import net.automatalib.incremental.dfa.Acceptance;

/**
 * Signature of a state. A signature consists of the list of all successor states
 * for all alphabet symbols, and the acceptance status.
 * 
 * @author Malte Isberner 
 *
 */
final class StateSignature {

	public final State[] successors;
	public Acceptance acceptance;
	private int hashCode;
	
	public StateSignature(int numSuccs, Acceptance acceptance) {
		this.successors = new State[numSuccs];
		this.acceptance = acceptance;
		updateHashCode();
	}
	
	public StateSignature(StateSignature other) {
		this.successors = other.successors.clone();
		this.acceptance = other.acceptance;
	}
	
	public StateSignature duplicate() {
		return new StateSignature(this);
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		return hashCode;
	}
	
	public void updateHashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result
				+ acceptance.hashCode();
		result = prime * result + Arrays.hashCode(successors);
		hashCode = result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (obj.getClass() != StateSignature.class)
			return false;
		StateSignature other = (StateSignature) obj;
		if(hashCode != other.hashCode)
			return false;
		if (acceptance != other.acceptance)
			return false;
		for(int i = 0; i < successors.length; i++) {
			if(successors[i] != other.successors[i])
				return false;
		}
		return true;
	}
	
	
	

}