CloudSim源代码学习——服务代理商（DatacenterBroker）

DatacenterBroker.java文件如下：

（其中，相关语句已经做好标注）

 /*
  * Title:        CloudSim Toolkit
  * Description:  CloudSim (Cloud Simulation) Toolkit for Modeling and Simulation of Clouds
  * Licence:      GPL - http://www.gnu.org/copyleft/gpl.html
  *
  * Copyright (c) 2009-2010, The University of Melbourne, Australia
  */
 package org.cloudbus.cloudsim;

 import java.util.ArrayList;//Resizable-array implementation of the List interface
 import java.util.HashMap;//散列表要解决的一个问题就是散列值的冲突问题，通常是两种方法：链表法和开放地址法。链表法就是将相同hash值的对象组织成一个链表放在hash值对应的槽位  （来源：http://www.yuloo.com/news/1012/527961.html）
 import java.util.LinkedList;//The class implements the Deque interface, providing first-in-first-out queue operations for add, poll, along with other stack and deque operations
 import java.util.List;//An ordered collection (also known as a sequence)
 import java.util.Map;//An object that maps keys to values

 import org.cloudbus.cloudsim.core.CloudSim;//This class extends the CloudSimCore to enable network simulation in CloudSim
 import org.cloudbus.cloudsim.core.CloudSimTags;//Contains various static command tags that indicate a type of action that needs to be undertaken by CloudSim entities when they receive or send events
 import org.cloudbus.cloudsim.core.SimEntity;//This class represents a simulation entity
 import org.cloudbus.cloudsim.core.SimEvent;//This class represents a simulation event which is passed between the entities in the simulation
 import org.cloudbus.cloudsim.lists.CloudletList;//CloudletList is a collection of operations on lists of Cloudlets
 import org.cloudbus.cloudsim.lists.VmList;//VmList is a collection of operations on lists of VMs

 /**DatacentreBroker类代表一经纪人行使用户角色，隐藏了虚拟机管理，如虚拟机创建，用户任务提交和虚拟机销毁
  * DatacentreBroker represents a broker
  * acting on behalf of a user. It hides VM management,
  * as vm creation, sumbission of cloudlets to this VMs
  * and destruction of VMs.
  *
  * @author        Rodrigo N. Calheiros
  * @author        Anton Beloglazov
  * @since        CloudSim Toolkit 1.0
  */
 public class DatacenterBroker extends SimEntity {

     // TODO: remove unnecessary variables移除不必要的变量

     /** The vm list. 虚拟机列表*/
     private List<? extends Vm> vmList;

     /** The vms created list. 虚拟机创建列表*/
     private List<? extends Vm> vmsCreatedList;

     /** The cloudlet list.云任务列表 */
     private List<? extends Cloudlet> cloudletList;

     /** The cloudlet submitted list. 云任务提交列表*/
     private List<? extends Cloudlet> cloudletSubmittedList;

     /** The cloudlet received list. 云任务接收列表*/
     private List<? extends Cloudlet> cloudletReceivedList;

     /** The cloudlets submitted. 提交的云任务*/
     private int cloudletsSubmitted;

     /** The vms requested. 请求的虚拟机*/
     private int vmsRequested;

     /** The vms acks.虚拟机确认 */
     private int vmsAcks;

     /** The vms destroyed.虚拟机销毁 */
     private int vmsDestroyed;

     /** The datacenter ids list. 数据中心ID列表*/
     private List<Integer> datacenterIdsList;

     /** The datacenter requested ids list.请求数据中心ID列表 */
     private List<Integer> datacenterRequestedIdsList;

     /** The vms to datacenters map. 虚拟机到数据中心映射*/
     private Map<Integer, Integer> vmsToDatacentersMap;

     /** The datacenter characteristics list. 数据中心特征列表*/
     private Map<Integer, DatacenterCharacteristics> datacenterCharacteristicsList;

     /**【创建新的数据中心代理对象】
      * Created a new DatacenterBroker object.
      *
      * @param name     name to be associated with this entity (as
      * required by Sim_entity class from simjava package)
      *
      * @throws Exception the exception
      *
      * @pre name != null
      * @post $none
      */
     public DatacenterBroker(String name) throws Exception {
         super(name);

         setVmList(new ArrayList<Vm>());
         setVmsCreatedList(new ArrayList<Vm>());
         setCloudletList(new ArrayList<Cloudlet>());
         setCloudletSubmittedList(new ArrayList<Cloudlet>());
         setCloudletReceivedList(new ArrayList<Cloudlet>());

         cloudletsSubmitted=0;//= 与（0）是什么区别
         setVmsRequested(0);
         setVmsAcks(0);
         setVmsDestroyed(0);

         setDatacenterIdsList(new LinkedList<Integer>());
         setDatacenterRequestedIdsList(new ArrayList<Integer>());
         setVmsToDatacentersMap(new HashMap<Integer, Integer>());
         setDatacenterCharacteristicsList(new HashMap<Integer, DatacenterCharacteristics>());
     }

     /**【方法 ： 发送给代理必须创建的虚拟机列表】
      * This method is used to send to the broker the list with
      * virtual machines that must be created.
      *
      * @param list the list
      *
      * @pre list !=null
      * @post $none
      */
     public void submitVmList(List<? extends Vm> list) {
         getVmList().addAll(list);
     }

     /**【方法 ： 发送云任务列表给代理】
      * This method is used to send to the broker the list of
      * cloudlets.
      *
      * @param list the list
      *
      * @pre list !=null
      * @post $none
      */
     public void submitCloudletList(List<? extends Cloudlet> list){
         getCloudletList().addAll(list);
     }

     /**（绑定云任务到指定虚拟机）
      * Specifies that a given cloudlet must run in a specific virtual machine.
      *
      * @param cloudletId ID of the cloudlet being bount to a vm
      * @param vmId the vm id
      *
      * @pre cloudletId > 0
      * @pre id > 0
      * @post $none
      */
     public void bindCloudletToVm(int cloudletId, int vmId){
         CloudletList.getById(getCloudletList(), cloudletId).setVmId(vmId);
     }

     /**处理可用于代理的事件
      * Processes events available for this Broker.
      *
      * @param ev    a SimEvent object
      *
      * @pre ev != null
      * @post $none
      */
     @Override//http://www.javaeye.com/wiki/topic/694939 参考注释
     public void processEvent(SimEvent ev) {//implements org.cloudbus.cloudsim.core.SimEntity.processEvent
         //Log.printLine(CloudSim.clock()+"[Broker]: event received:"+ev.getTag());
         switch (ev.getTag()){
             // Resource characteristics request资源特征请求
             case CloudSimTags.RESOURCE_CHARACTERISTICS_REQUEST:
                 processResourceCharacteristicsRequest(ev);
                 break;
             // Resource characteristics answer资源特征应答
             case CloudSimTags.RESOURCE_CHARACTERISTICS:
                 processResourceCharacteristics(ev);
                 break;
             // VM Creation answer 虚拟机创建应答
             case CloudSimTags.VM_CREATE_ACK:
                    processVmCreate(ev);
                    break;
             //A finished cloudlet returned 返回一个完成的云任务
             case CloudSimTags.CLOUDLET_RETURN:
                 processCloudletReturn(ev);
                 break;
             // if the simulation finishes 仿真完成
             case CloudSimTags.END_OF_SIMULATION:
                 shutdownEntity();
                 break;
             // other unknown tags are processed by this method 处理unknown tags
             default:
                 processOtherEvent(ev);
                 break;
         }
     }

     /**
      * Process the return of a request for the characteristics of a PowerDatacenter（功率意识数据中心）.
      *
      * @param ev a SimEvent object
      *
      * @pre ev != $null
      * @post $none
      */
     protected void processResourceCharacteristics(SimEvent ev) {
         DatacenterCharacteristics characteristics = (DatacenterCharacteristics) ev.getData();
         getDatacenterCharacteristicsList().put(characteristics.getId(), characteristics);

         if (getDatacenterCharacteristicsList().size() == getDatacenterIdsList().size()) {
             setDatacenterRequestedIdsList(new ArrayList<Integer>());
             createVmsInDatacenter(getDatacenterIdsList().get(0));
         }
     }

     /**处理PowerDatacenter特征的请求
      * Process a request for the characteristics of a PowerDatacenter.
      *
      * @param ev a SimEvent object
      *
      * @pre ev != $null
      * @post $none
      */
     protected void processResourceCharacteristicsRequest(SimEvent ev) {
         setDatacenterIdsList(CloudSim.getCloudResourceList());
         setDatacenterCharacteristicsList(new HashMap<Integer, DatacenterCharacteristics>());

         Log.printLine(CloudSim.clock()+": "+getName()+ ": Cloud Resource List received with "+getDatacenterIdsList().size()+" resource(s)");

         for (Integer datacenterId : getDatacenterIdsList()) {
             sendNow(datacenterId, CloudSimTags.RESOURCE_CHARACTERISTICS, getId());
         }
     }

     /**【请求虚拟机响应应答】
      * Process the ack received due to a request for VM creation.
      *
      * @param ev a SimEvent object
      *
      * @pre ev != null
      * @post $none
      */
     protected void processVmCreate(SimEvent ev) {
         int[] data = (int[]) ev.getData();
         int datacenterId = data[0];
         int vmId = data[1];
         int result = data[2];

         if (result == CloudSimTags.TRUE) {
             getVmsToDatacentersMap().put(vmId, datacenterId);
             getVmsCreatedList().add(VmList.getById(getVmList(), vmId));
             Log.printLine(CloudSim.clock()+": "+getName()+ ": VM #"+vmId+" has been created in Datacenter #" + datacenterId + ", Host #" + VmList.getById(getVmsCreatedList(), vmId).getHost().getId());
         } else {
             Log.printLine(CloudSim.clock()+": "+getName()+ ": Creation of VM #"+vmId+" failed in Datacenter #" + datacenterId);
         }

         incrementVmsAcks();

         if (getVmsCreatedList().size() == getVmList().size() - getVmsDestroyed()) { // all the requested VMs have been created 所有请求虚拟机已创建
             submitCloudlets();
         } else {
             if (getVmsRequested() == getVmsAcks()) { // all the acks received, but some VMs were not created所有响应接受。但一些虚拟机没有创建
                 // find id of the next datacenter that has not been tried找出下一个数据中心ID
                 for (int nextDatacenterId : getDatacenterIdsList()) {
                     if (!getDatacenterRequestedIdsList().contains(nextDatacenterId)) {
                         createVmsInDatacenter(nextDatacenterId);
                         return;
                     }
                 }

                 //all datacenters already queried 咨询了所有的数据中心
                 if (getVmsCreatedList().size() > 0) { //if some vm were created 一些虚拟机已经创建
                     submitCloudlets();
                 } else { //no vms created. abort停止
                     Log.printLine(CloudSim.clock() + ": " + getName() + ": none of the required VMs could be created. Aborting");
                     finishExecution();
                 }
             }
         }
     }

     /**【处理云任务返回事件】
      * Process a cloudlet return event.
      *
      * @param ev a SimEvent object
      *
      * @pre ev != $null
      * @post $none
      */
     protected void processCloudletReturn(SimEvent ev) {
         Cloudlet cloudlet = (Cloudlet) ev.getData();
         getCloudletReceivedList().add(cloudlet);
         Log.printLine(CloudSim.clock()+": "+getName()+ ": Cloudlet "+cloudlet.getCloudletId()+" received");
         cloudletsSubmitted--;
         if (getCloudletList().size()==0&&cloudletsSubmitted==0) { //all cloudlets executed 所有云任务已执行完
             Log.printLine(CloudSim.clock()+": "+getName()+ ": All Cloudlets executed. Finishing...");
             clearDatacenters();
             finishExecution();
         } else { //some cloudlets haven't finished yet 一些任务没完成
             if (getCloudletList().size()>0 && cloudletsSubmitted==0) {
                 //all the cloudlets sent finished. It means that some bount
                 //cloudlet is waiting its VM be created云任务发送完毕
                 clearDatacenters();
                 createVmsInDatacenter(0);
             }

         }
     }

     /**【重写 创建一个新的不同类型的代理】
      * Overrides this method when making a new and different type of Broker.
      * This method is called by {@link #body()} for incoming unknown tags.
      *
      * @param ev   a SimEvent object
      *
      * @pre ev != null
      * @post $none
      */
     protected void processOtherEvent(SimEvent ev){
         if (ev == null){
             Log.printLine(getName() + ".processOtherEvent(): " + "Error - an event is null.");
             return;
         }

         Log.printLine(getName() + ".processOtherEvent(): " + "Error - event unknown by this DatacenterBroker.");
     }

     /**在数据中心里创建虚拟机
      * Create the virtual machines in a datacenter.
      *
      * @param datacenterId Id of the chosen PowerDatacenter
      *
      * @pre $none
      * @post $none
      */
     protected void createVmsInDatacenter(int datacenterId) {
         // send as much vms as possible for this datacenter before trying the next one
         int requestedVms = 0;
         String datacenterName = CloudSim.getEntityName(datacenterId);
         for (Vm vm : getVmList()) {
             if (!getVmsToDatacentersMap().containsKey(vm.getId())) {
                 Log.printLine(CloudSim.clock() + ": " + getName() + ": Trying to Create VM #" + vm.getId() + " in " + datacenterName);
                 sendNow(datacenterId, CloudSimTags.VM_CREATE_ACK, vm);
                 requestedVms++;
             }
         }

         getDatacenterRequestedIdsList().add(datacenterId);

         setVmsRequested(requestedVms);
         setVmsAcks(0);
     }

     /**提交云任务到虚拟机
      * Submit cloudlets to the created VMs.
      *
      * @pre $none
      * @post $none
      */
     protected void submitCloudlets() {
         int vmIndex = 0;
         for (Cloudlet cloudlet : getCloudletList()) {
             Vm vm;
             if (cloudlet.getVmId() == -1) { //if user didn't bind this cloudlet and it has not been executed yet用户没有绑定云任务
                 vm = getVmsCreatedList().get(vmIndex);
             } else { //submit to the specific vm提交给专门的虚拟机
                 vm = VmList.getById(getVmList(), cloudlet.getVmId());
                 if (vm == null) { // vm was not created 虚拟机没有创建
                     Log.printLine(CloudSim.clock()+": "+getName()+ ": Postponing execution of cloudlet "+cloudlet.getCloudletId()+": bount VM not available");
                     continue;
                 }
             }

             Log.printLine(CloudSim.clock()+": "+getName()+ ": Sending cloudlet "+cloudlet.getCloudletId()+" to VM #"+vm.getId());
             cloudlet.setVmId(vm.getId());
             sendNow(getVmsToDatacentersMap().get(vm.getId()), CloudSimTags.CLOUDLET_SUBMIT, cloudlet);
             cloudletsSubmitted++;
             vmIndex = (vmIndex + 1) % getVmsCreatedList().size();
             getCloudletSubmittedList().add(cloudlet);
         }

         //从等待列表中除去提交的任务  remove submitted cloudlets from waiting list
         for (Cloudlet cloudlet : getCloudletSubmittedList()) {
             getCloudletList().remove(cloudlet);
         }
     }

     /**销毁虚拟机
      * Destroy the virtual machines running in datacenters.
      *
      * @pre $none
      * @post $none
      */
     protected void clearDatacenters() {
         for (Vm vm : getVmsCreatedList()) {
             Log.printLine(CloudSim.clock() + ": " + getName() + ": Destroying VM #" + vm.getId());
             sendNow(getVmsToDatacentersMap().get(vm.getId()), CloudSimTags.VM_DESTROY, vm);
         }

         getVmsCreatedList().clear();
     }

     /**仿真结束
      * Send an internal event communicating the end of the simulation.
      *
      * @pre $none
      * @post $none
      */
     private void finishExecution() {
         sendNow(getId(), CloudSimTags.END_OF_SIMULATION);
     }

     /* (non-Javadoc)
      * @see cloudsim.core.SimEntity#shutdownEntity()
      */
     @Override
     public void shutdownEntity() {
         Log.printLine(getName() + " is shutting down...");
     }

     /* (non-Javadoc)
      * @see cloudsim.core.SimEntity#startEntity()
      */
     @Override
     public void startEntity() {
         Log.printLine(getName() + " is starting...");
         schedule(getId(), 0, CloudSimTags.RESOURCE_CHARACTERISTICS_REQUEST);
     }

     /**虚拟机列表
      * Gets the vm list.
      *
      * @param <T> the generic type
      * @return the vm list
      */
     @SuppressWarnings("unchecked")
     public <T extends Vm> List<T> getVmList() {
         return (List<T>) vmList;
     }

     /**设置虚拟机列表
      * Sets the vm list.
      *
      * @param <T> the generic type
      * @param vmList the new vm list
      */
     protected <T extends Vm> void setVmList(List<T> vmList) {
         this.vmList = vmList;
     }

     /**云任务列表
      * Gets the cloudlet list.
      *
      * @param <T> the generic type
      * @return the cloudlet list
      */
     @SuppressWarnings("unchecked")
     public <T extends Cloudlet> List<T> getCloudletList() {
         return (List<T>) cloudletList;
     }

     /**设置云任务列表
      * Sets the cloudlet list.
      *
      * @param <T> the generic type
      * @param cloudletList the new cloudlet list
      */
     protected <T extends Cloudlet> void setCloudletList(List<T> cloudletList) {
         this.cloudletList = cloudletList;
     }

     /**云任务提交列表
      * Gets the cloudlet submitted list.
      *
      * @param <T> the generic type
      * @return the cloudlet submitted list
      */
     @SuppressWarnings("unchecked")
     public <T extends Cloudlet> List<T> getCloudletSubmittedList() {
         return (List<T>) cloudletSubmittedList;
     }

     /**设置云任务提交列表
      * Sets the cloudlet submitted list.
      *
      * @param <T> the generic type
      * @param cloudletSubmittedList the new cloudlet submitted list
      */
     protected <T extends Cloudlet> void setCloudletSubmittedList(List<T> cloudletSubmittedList) {
         this.cloudletSubmittedList = cloudletSubmittedList;
     }

     /**云任务接收列表
      * Gets the cloudlet received list.
      *
      * @param <T> the generic type
      * @return the cloudlet received list
      */
     @SuppressWarnings("unchecked")
     public <T extends Cloudlet> List<T> getCloudletReceivedList() {
         return (List<T>) cloudletReceivedList;
     }

     /**设置云任务接收列表
      * Sets the cloudlet received list.
      *
      * @param <T> the generic type
      * @param cloudletReceivedList the new cloudlet received list
      */
     protected <T extends Cloudlet> void setCloudletReceivedList(List<T> cloudletReceivedList) {
         this.cloudletReceivedList = cloudletReceivedList;
     }

     /**虚拟机列表 ？？？
      * Gets the vm list.
      *
      * @param <T> the generic type
      * @return the vm list
      */
     @SuppressWarnings("unchecked")
     public <T extends Vm> List<T> getVmsCreatedList() {
         return (List<T>) vmsCreatedList;
     }

     /**
      * Sets the vm list.
      *
      * @param <T> the generic type
      * @param vmsCreatedList the vms created list
      */
     protected <T extends Vm> void setVmsCreatedList(List<T> vmsCreatedList) {
         this.vmsCreatedList = vmsCreatedList;
     }

     /**虚拟机请求
      * Gets the vms requested.
      *
      * @return the vms requested
      */
     protected int getVmsRequested() {
         return vmsRequested;
     }

     /**
      * Sets the vms requested.
      *
      * @param vmsRequested the new vms requested
      */
     protected void setVmsRequested(int vmsRequested) {
         this.vmsRequested = vmsRequested;
     }

     /**虚拟机响应
      * Gets the vms acks.
      *
      * @return the vms acks
      */
     protected int getVmsAcks() {
         return vmsAcks;
     }

     /**
      * Sets the vms acks.
      *
      * @param vmsAcks the new vms acks
      */
     protected void setVmsAcks(int vmsAcks) {
         this.vmsAcks = vmsAcks;
     }

     /**增加虚拟机响应
      * Increment vms acks.
      */
     protected void incrementVmsAcks() {
         this.vmsAcks++;
     }

     /**销毁虚拟机
      * Gets the vms destroyed.
      *
      * @return the vms destroyed
      */
     protected int getVmsDestroyed() {
         return vmsDestroyed;
     }

     /**
      * Sets the vms destroyed.
      *
      * @param vmsDestroyed the new vms destroyed
      */
     protected void setVmsDestroyed(int vmsDestroyed) {
         this.vmsDestroyed = vmsDestroyed;
     }

     /**数据执行ID
      * Gets the datacenter ids list.
      *
      * @return the datacenter ids list
      */
     protected List<Integer> getDatacenterIdsList() {
         return datacenterIdsList;
     }

     /**
      * Sets the datacenter ids list.
      *
      * @param datacenterIdsList the new datacenter ids list
      */
     protected void setDatacenterIdsList(List<Integer> datacenterIdsList) {
         this.datacenterIdsList = datacenterIdsList;
     }

     /**虚拟机到数据中心映射
      * Gets the vms to datacenters map.
      *
      * @return the vms to datacenters map
      */
     protected Map<Integer, Integer> getVmsToDatacentersMap() {
         return vmsToDatacentersMap;
     }

     /**
      * Sets the vms to datacenters map.
      *
      * @param vmsToDatacentersMap the vms to datacenters map
      */
     protected void setVmsToDatacentersMap(Map<Integer, Integer> vmsToDatacentersMap) {
         this.vmsToDatacentersMap = vmsToDatacentersMap;
     }

     /**数据中心特征列表
      * Gets the datacenter characteristics list.
      *
      * @return the datacenter characteristics list
      */
     protected Map<Integer, DatacenterCharacteristics> getDatacenterCharacteristicsList() {
         return datacenterCharacteristicsList;
     }

     /**
      * Sets the datacenter characteristics list.
      *
      * @param datacenterCharacteristicsList the datacenter characteristics list
      */
     protected void setDatacenterCharacteristicsList(Map<Integer, DatacenterCharacteristics> datacenterCharacteristicsList) {
         this.datacenterCharacteristicsList = datacenterCharacteristicsList;
     }

     /**
      * Gets the datacenter requested ids list.
      *
      * @return the datacenter requested ids list
      */
     protected List<Integer> getDatacenterRequestedIdsList() {
         return datacenterRequestedIdsList;
     }

     /**
      * Sets the datacenter requested ids list.
      *
      * @param datacenterRequestedIdsList the new datacenter requested ids list
      */
     protected void setDatacenterRequestedIdsList(List<Integer> datacenterRequestedIdsList) {
         this.datacenterRequestedIdsList = datacenterRequestedIdsList;
     }

 }