StateMachineController.java

/*
 * Copyright 2016 the original author or authors.
 *
 * 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 demo.datajpa;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.statemachine.StateMachine;
import org.springframework.statemachine.config.StateMachineFactory;
import org.springframework.statemachine.data.RepositoryTransition;
import org.springframework.statemachine.data.TransitionRepository;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class StateMachineController {

	@Autowired
	private StateMachineFactory<String, String> stateMachineFactory;

	@Autowired
	private TransitionRepository<? extends RepositoryTransition> transitionRepository;

	@RequestMapping("/")
	public String home() {
		return "redirect:/state";
	}

	@RequestMapping("/state")
	public String feedAndGetStates(@RequestParam(value = "events", required = false) List<String> events, Model model) throws Exception {

		StateMachine<String, String> stateMachine = stateMachineFactory.getStateMachine();
		StateMachineLogListener listener = new StateMachineLogListener();
		stateMachine.addStateListener(listener);
		stateMachine.start();
		if (events != null) {
			for (String event : events) {
				stateMachine.sendEvent(event);
			}
		}
		stateMachine.stop();
		model.addAttribute("allEvents", getEvents());
		model.addAttribute("messages", createMessages(listener.getMessages()));
		return "states";
	}

	private String[] getEvents() {
		List<String> events = new ArrayList<>();
		for (RepositoryTransition t : transitionRepository.findAll()) {
			events.add(t.getEvent());
		}
		return events.toArray(new String[0]);
	}

	private String createMessages(List<String> messages) {
		StringBuilder buf = new StringBuilder();
		for (String message : messages) {
			buf.append(message);
			buf.append("\n");
		}
		return buf.toString();
	}

}