CloudSim源代码学习之CloudletScheduler类.doc

* Title: CloudSim Toolkit * Description: CloudSim (Cloud Simulation) Toolkit for Modeling and Simulation of Clouds * Licence: GPL - /copyleft/gpl.html * * Copyright (c) 2009-2010, The University of Melbourne, Australia */ package org.cloudbus.cloudsim; import java.util.List;//有序的集合（也被称为sequence）。该接口的用户可以精确控制列表元素插入的位置。 用户可以通过整数下标（列表中的位置）访问、查找列表中的元素。 /**【云任务调度】代表虚拟机执行调度协议的抽象类 * CloudletScheduler is an abstract class that represents the policy of * scheduling performed by a virtual machine. So, classes * extending this must execute Cloudlets. Also, the interface for cloudlet * management is also implemented in this class. 云任务管理也在这个类实现 * * @author Rodrigo N. Calheiros * @author Anton Beloglazov * @since CloudSim Toolkit 1.0 */ public abstract class CloudletScheduler { //抽象类是不允许实例化的类，因此一般它需要被进行扩展继承 /** The previous time. *///先前时间 private double previousTime; /** The current mips share. *///现在mips共享 private ListDouble currentMipsShare; /**创建一个新的运任务调度对象 实际仿真前先调用 * Creates a new CloudletScheduler object. This method must be invoked * before starting the actual simulation. * * @pre $none * @post $none */ public CloudletScheduler() { setPreviousTime(0.0); } /** * Updates the processing of cloudlets running under management of this scheduler. * * @param currentTime current simulation time * @param mipsShare array with MIPS share of each processor available to the scheduler * * @return 云任务预测最早完成时间time predicted completion time of the earliest finishing cloudlet, or 0 * if there is no next events * * @pre currentTime = 0 * @post $none */ public abstract double updateVmProcessing(double currentTime, ListDouble mipsShare); /** * Receives an cloudlet to be executed in the VM managed by this scheduler. *虚拟机接受执行一个云任务 * @param gl the submited cloudlet 提交的云任务 * @param fileTransferTime 文件传输时间 time required to move the required files from the SAN to the VM * * @return 云任务期待完成时间expected finish time