SimpleQueuePopScheduler.java

/*******************************************************************************
 * Copyright 2013 Michael Marconi
 * 
 * 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 oncue.scheduler;

import java.util.Collection;
import java.util.Iterator;

import oncue.backingstore.BackingStore;
import oncue.common.messages.Job;
import oncue.common.messages.SimpleWorkRequest;

/**
 * This concrete implementation of {@linkplain AbstractScheduler} employs a very
 * simple scheduling strategy that pops the next job off the queue and hands it
 * to the first requesting agent.
 * 
 * This is strictly first-come-first-served: which ever agent makes the request
 * first will get the job.
 */
public class SimpleQueuePopScheduler extends AbstractScheduler<SimpleWorkRequest> {

	public SimpleQueuePopScheduler(Class<? extends BackingStore> backingStore) {
		super(backingStore);
	}

	@Override
	protected void scheduleJobs(SimpleWorkRequest workRequest) {
		String agent = getSender().path().toString();

		Collection<String> workerTypes = getAgentWorkers().get(agent);
		if (workerTypes == null)
			throw new RuntimeException("No worker types registered for agent " + agent);

		// Create the schedule
		Schedule schedule = new Schedule();
		Iterator<Job> iterator = unscheduledJobs.iterator();
		while (iterator.hasNext()) {
			Job job = iterator.next();
			if (workRequest.getWorkerTypes().contains(job.getWorkerType()))
				schedule.setJob(getSender(), job);
		}

		// Dispatch the schedule
		dispatchJobs(schedule);
	}

}