/*
* 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) 2009-2012, The University of Melbourne, Australia
*/
package org.cloudbus.cloudsim;
import java.util.List;
import java.util.Map;
/**
* VmAllocationPolicy is an abstract class that represents the provisioning policy of hosts to
* virtual machines in a Datacenter. It allocates hosts for placing VMs.
* It supports two-stage commit of reservation of hosts: first, we
* reserve the host and, once committed by the user, it is effectively allocated to he/she.
*
* @author Rodrigo N. Calheiros
* @author Anton Beloglazov
* @since CloudSim Toolkit 1.0
*/
public abstract class VmAllocationPolicy {
/** The host list. */
private List<? extends Host> hostList;
/**
* Creates a new VmAllocationPolicy object.
*
* @param list Machines available in a {@link Datacenter}
* @pre $none
* @post $none
*/
public VmAllocationPolicy(List<? extends Host> list) {
setHostList(list);
}
/**
* Allocates a host for a given VM.
*
* @param vm the VM to allocate a host to
* @return $true if the host could be allocated; $false otherwise
* @pre $none
* @post $none
*/
public abstract boolean allocateHostForVm(Vm vm);
/**
* Allocates a specified host for a given VM.
*
* @param vm virtual machine which the host is reserved to
* @param host host to allocate the the given VM
* @return $true if the host could be allocated; $false otherwise
* @pre $none
* @post $none
*/
public abstract boolean allocateHostForVm(Vm vm, Host host);
/**
* Optimize allocation of the VMs according to current utilization.
*
* @param vmList the vm list
* @return the array list< hash map< string, object>>
*
* @todo It returns a list of maps, where each map key is a string
* and stores an object. What in fact are the keys and values of this
* Map? Neither this class or its subclasses implement the method
* or have clear documentation. The only sublcass is the {@link VmAllocationPolicySimple}.
*
*/
public abstract List<Map<String, Object>> optimizeAllocation(List<? extends Vm> vmList);
/**
* Releases the host used by a VM.
*
* @param vm the vm to get its host released
* @pre $none
* @post $none
*/
public abstract void deallocateHostForVm(Vm vm);
/**
* Get the host that is executing the given VM.
*
* @param vm the vm
* @return the Host with the given vmID; $null if not found
*
* @pre $none
* @post $none
*/
public abstract Host getHost(Vm vm);
/**
* Get 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
*/
public abstract Host getHost(int vmId, int userId);
/**
* Sets the host list.
*
* @param hostList the new host list
*/
protected void setHostList(List<? extends Host> hostList) {
this.hostList = hostList;
}
/**
* Gets the host list.
*
* @return the host list
*/
@SuppressWarnings("unchecked")
public <T extends Host> List<T> getHostList() {
return (List<T>) hostList;
}
}