/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.oodt.cas.resource.scheduler;

//OODT imports
import org.apache.oodt.cas.resource.batchmgr.Batchmgr;
import org.apache.oodt.cas.resource.jobqueue.JobQueue;
import org.apache.oodt.cas.resource.monitor.Monitor;
import org.apache.oodt.cas.resource.scheduler.QueueManager;
import org.apache.oodt.cas.resource.structs.JobSpec;
import org.apache.oodt.cas.resource.structs.ResourceNode;
import org.apache.oodt.cas.resource.structs.exceptions.SchedulerException;

/**
 * @author woollard
 * @author bfoster
 * @version $Revision$
 * 
 * <p>
 * A scheduler interface.
 * </p>
 * 
 */
public interface Scheduler extends Runnable{

	/**
	 * Schedules a job to be executed by a particular batch manager.
	 * 
	 * @param spec
	 *            The {@link JobSpec} to schedule for execution.
	 * @return Whether the job was successfully scheduled or not.
  * @throws SchedulerException If there was any error scheduling
  * the given {@link JobSpec}.
	 */
	public boolean schedule(JobSpec spec) throws SchedulerException;


 /**
  * Returns the ResourceNode that is considered to be <quote>most available</quote>
  * within our underlying set of resources for the given JobSpec.
  * @param spec The JobSpec to find an available node for.
  * @return The {@link ResourceNode} best suited to handle this {@link JobSpec}
  * @throws SchedulerException If any error occurs.
  */
 public ResourceNode nodeAvailable(JobSpec spec) throws SchedulerException;

 /**
  * 
  * @return The underlying {@link Monitor} used by this
  * Scheduler.
  */
 public Monitor getMonitor();
 
 /**
  * 
  * @return The underlying {@link Batchmgr} used by this
  * Scheduler.
  */
 public Batchmgr getBatchmgr();
 
 
 /**
  * 
  * @return The underlying {@link JobQueue} used by this
  * Scheduler.
  */
 public JobQueue getJobQueue();

 /**
  * 
  * @return The underlying {@link QueueManager} used by this
  * Scheduler.
  */
 public QueueManager getQueueManager();
 
}