/*
* Copyright 2014 Groupon, Inc
* Copyright 2014 The Billing Project, LLC
*
* Groupon licenses this file to you 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 org.killbill.automaton.graph;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import org.killbill.automaton.State;
import org.killbill.automaton.StateMachine;
import org.killbill.automaton.Transition;
public class Helpers {
// Might be nicer to return Set<State>, but a bit more difficult to work with
// We assume state names are unique anyways
public static Set<String> findInitialStates(final StateMachine stateMachine) {
return findEdgeStates(stateMachine, true);
}
public static Set<String> findFinalStates(final StateMachine stateMachine) {
return findEdgeStates(stateMachine, false);
}
private static Set<String> findEdgeStates(final StateMachine stateMachine, final boolean initial) {
final Set<String> edgeStates = new HashSet<String>();
final Collection<String> complementStates = new HashSet<String>();
for (final Transition transition : stateMachine.getTransitions()) {
final String stateName = initial ? transition.getFinalState().getName() : transition.getInitialState().getName();
complementStates.add(stateName);
}
for (final State state : stateMachine.getStates()) {
if (!complementStates.contains(state.getName())) {
edgeStates.add(state.getName());
}
}
return edgeStates;
}
}