QueueManager.java

/**
 * 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 com.chinamobile.bcbsp.bspcontroller;

import java.io.IOException;

//import java.util.List;
//import java.util.ArrayList;
//import java.util.Collections;
//import java.util.Comparator;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.hadoop.conf.Configuration;

/**
 * A BSPJob Queue Manager.
 * 
 * @author
 * @version
 */
public class QueueManager {

    private ConcurrentMap<String, Queue<JobInProgress>> queues = new ConcurrentHashMap<String, Queue<JobInProgress>>();

    public QueueManager(Configuration conf) {
    }

    /**
     * Initialize a job.
     * 
     * @param job
     *            required initialzied.
     */
    public void initJob(JobInProgress job) throws IOException{
        job.initStaffs();        
    }

    /**
     * Add a job to the specified queue.
     * 
     * @param name
     *            of the queue.
     * @param job
     *            to be added.
     */
    public void addJob(String name, JobInProgress job) {
        Queue<JobInProgress> queue = queues.get(name);
        if (null != queue)
            queue.addJob(job);
    }

    /**
     * Sort jobs by priority and then by start time.
     * 
     * @param name
     *              of the queue
     */
    public void resortWaitQueue(String name) {
        Queue<JobInProgress> queue = queues.get(name);
        if (null != queue) {
            queue.resortQueue();
        }
    }

    /**
     * Remove a job from the head of a designated queue.
     * 
     * @param name
     *            from which a job is removed.
     * @param job
     *            to be removed from the queue.
     */
    public void removeJob(String name, JobInProgress job) {
        Queue<JobInProgress> queue = queues.get(name);
        if (null != queue)
            queue.removeJob(job);
    }

    /**
     * Move a job from a queue to another.
     * 
     * @param from
     *            a queue a job is to be removed.
     * @param to
     *            a queue a job is to be added.
     */
    public void moveJob(String from, String to, JobInProgress job) {
        synchronized (queues) {
            removeJob(from, job);
            addJob(to, job);
        }
    }

    /**
     * Create a FCFS queue with the name provided.
     * 
     * @param name
     *            of the queue.
     */
    public void createFCFSQueue(String name) {
        queues.putIfAbsent(name, new FCFSQueue(name));
    }

    /**
     * Find Queue according to the name specified.
     * 
     * @param name
     *            of the queue.
     * @return queue of JobInProgress
     */
    public Queue<JobInProgress> findQueue(String name) {
        return queues.get(name);
    }

}