CloudSim源代码学习之VmAllocationPolicySimple.doc

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：/news/1012/527961.html）import java.util.List;/An ordered collection (also known as a sequence)import java.util.Map;/An object that maps keys to valuesimport org.cloudbus.cloudsim.core.CloudSim;/* * VmAllocationPolicySimple is an VmAllocationPolicy that * chooses, as the host for a VM, （the host with * less PEs in use.） * * authorRodrigo N. Calheiros * authorAnton Beloglazov * sinceCloudSim Toolkit 1.0 */public class VmAllocationPolicySimple extends VmAllocationPolicy /* The vm table. 虚拟机表*/private Map vmTable;/* The used pes. 已使用的PE*/private Map usedPes;/* The free pes.空闲的PE */private List freePes;/*创建新的对象 * Creates the new VmAllocationPolicySimple object. * * param list the list * * pre $none * post $none */public VmAllocationPolicySimple(List list) super(list);setFreePes(new ArrayList();for (Host host : getHostList() getFreePes().add(host.getPesNumber();setVmTable(new HashMap();setUsedPes(new HashMap();/*分配一主机给指定的VM * Allocates a host for a given VM. * * param vm VM specification * * return $true if the host could be allocated; $false otherwise * * pre $none * post $none */Overridepublic boolean allocateHostForVm(Vm vm) /implements org.cloudbus.cloudsim.VmAllocationPolicy.allocateHostForVmint requiredPes = vm.getPesNumber();boolean result = false;int tries = 0;List freePesTmp = new ArrayList();for (Integer freePes : getFreePes() freePesTmp.add(freePes);if (!getVmTable().containsKey(vm.getUid() /if this vm was not created虚拟机没创建do /we still trying until we find a host or until we try all of themint moreFree = Integer.MIN_VALUE;int idx = -1;/we want the host with less pes in use较少的pe使用for (int i=0; i moreFree) /moreFree = Integer.MIN_VALUE最小值moreFree = freePesTmp.get(i);idx = i;Host host = getHostList().get(idx);result = host.vmCreate(vm);if (result) /if vm were succesfully created in the host虚拟机已成功创建/Log.printLine(VmAllocationPolicy: VM #+vm.getVmId()+ Chosen host: #+host.getMachineID()+ idx:+idx);getVmTable().put(vm.getUid(), host);getUsedPes().put(vm.getUid(), requiredPes);getFreePes().set(idx, getFreePes().get(idx) - requiredPes);result = true;break; else freePesTmp.set(idx, Integer.MIN_VALUE);tries+; while (!result & tries getFreePes().size();return result;/*释放主机 * Releases the host used by a VM. * * param vm the vm * * pre $none * post none */Overridepublic void deallocateHostForVm(Vm vm) /implements org.cloudbus.cloudsim.VmAllocationPolicy.deallocateHostForVmHost host = getVmTable().remove(vm.getUid();int idx = getHostList().indexOf(host);int pes = getUsedPes().remove(vm.getUid();if (host != null) host.vmDestroy(vm);getFreePes().set(idx, getFreePes().get(idx) + pes);/*属于特定用户指定虚拟机的主机 * Gets the host that is executing the given VM belonging to the * given user. * * param vm the vm * * return the Host with the given vmID and userID; $null if not found * * pre $none * post $none */Overridepublic Host getHost(Vm vm) /implements org.cloudbus.cloudsim.VmAllocationPolicy.getHostreturn getVmTable().get(vm.getUid();/*与上面有什么不同 * Gets the host that is executing the given VM belonging to the * given user. * * param vmId the vm id * param userId the user id * * return the Host with the given vmID and userID; $null if not found * * pre $none * post $none */Overridepublic Host getHost(int vmId, int userId) /implements org.cloudbus.cloudsim.VmAllocationPolicy.getHostreturn getVmTable().get(Vm.getUid(userId, vmId);/*获取vm表 * Gets the vm table. * * return the vm table */public Map getVmTable() return vmTable;/*设置vm表 * Sets the vm table. * * param vmTable the vm table */protected void setVmTable(Map vmTable) this.vmTable = vmTable;/*已使用的PE * Gets the used pes. * * return the used pes */protected Map getUsedPes() return usedPes;/*设置已使用的pe * Sets the used pes. * * param usedPes the used pes */protected void setUsedPes(Map usedPes) this.usedPes = usedPes;/*空闲的pe * Gets the free pes. * * return the free pes */protected List getFreePes() return freePes;/*设置空闲pe * Sets the free pes. * * param freePes the new free pes */protected void setFreePes(List freePes) this.freePes = freePes;/以下不知道具体作用！/* (non-Javadoc) * see cloudsim.VmAllocationPolicy#optimizeAllocation(double, cloudsim.VmList, double) */Overridepublic ListMap optimizeAllocation(List vmList) / TODO Auto-generated method stubreturn null;/* (non-Javadoc) * see org.cloudbus.cloudsim.VmAllocationPolicy#allocateHostForVm(org.cloudbus.cloudsim.Vm, org.cloudbus.cloudsim.Host) */Overridepublic boolean allocateHostForVm(Vm vm, Ho