net.automatalib.util.ts.traversal.BFSOrderIterator Maven / Gradle / Ivy
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This artifact provides various common utility operations for analyzing and manipulating
automata and graphs, such as traversal, minimization and copying.
/* Copyright (C) 2013-2019 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.util.ts.traversal;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Iterator;
import java.util.Queue;
import net.automatalib.commons.util.mappings.MutableMapping;
import net.automatalib.ts.simple.SimpleTS;
import net.automatalib.util.traversal.VisitedState;
public class BFSOrderIterator implements Iterator {
private final Collection inputs;
private final SimpleTS ts;
private final Queue bfsQueue = new ArrayDeque<>();
private final MutableMapping seen;
public BFSOrderIterator(SimpleTS ts, Collection inputs) {
this.ts = ts;
this.inputs = inputs;
Collection initial = ts.getInitialStates();
bfsQueue.addAll(initial);
seen = ts.createStaticStateMapping();
for (S state : initial) {
seen.put(state, VisitedState.VISITED);
}
}
@Override
public boolean hasNext() {
return !bfsQueue.isEmpty();
}
@Override
public S next() {
S state = bfsQueue.poll();
for (I input : inputs) {
Collection succs = ts.getSuccessors(state, input);
for (S succ : succs) {
if (seen.put(succ, VisitedState.VISITED) != VisitedState.VISITED) {
bfsQueue.add(succ);
}
}
}
return state;
}
}