/*
* 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.provisioners;
import org.cloudbus.cloudsim.Vm;
/**
* RamProvisioner is an abstract class that represents the provisioning policy used by a host
* to allocate memory to virtual machines inside it.
* Each host has to have its own instance of a RamProvisioner.
* When extending this class, care must be taken to guarantee that the field
* availableMemory will always contain the amount of free memory available for future allocations.
*
* @author Rodrigo N. Calheiros
* @author Anton Beloglazov
* @since CloudSim Toolkit 1.0
*/
public abstract class RamProvisioner {
/** The total ram capacity from the host that the provisioner can allocate to VMs. */
private int ram;
/** The available ram. */
private int availableRam;
/**
* Creates the new RamProvisioner.
*
* @param ram The total ram capacity from the host that the provisioner can allocate to VMs.
*
* @pre ram>=0
* @post $none
*/
public RamProvisioner(int ram) {
setRam(ram);
setAvailableRam(ram);
}
/**
* Allocates RAM for a given VM.
*
* @param vm the virtual machine for which the RAM is being allocated
* @param ram the RAM to be allocated to the VM
*
* @return $true if the RAM could be allocated; $false otherwise
*
* @pre $none
* @post $none
*/
public abstract boolean allocateRamForVm(Vm vm, int ram);
/**
* Gets the allocated RAM for a given VM.
*
* @param vm the VM
*
* @return the allocated RAM for the vm
*/
public abstract int getAllocatedRamForVm(Vm vm);
/**
* Releases RAM used by a VM.
*
* @param vm the vm
*
* @pre $none
* @post none
*/
public abstract void deallocateRamForVm(Vm vm);
/**
* Releases RAM used by all VMs.
*
* @pre $none
* @post none
*/
public void deallocateRamForAllVms() {
setAvailableRam(getRam());
}
/**
* Checks if it is possible to change the current allocated RAM for the VM
* to a new amount, depending on the available RAM.
*
* @param vm the vm to check if there is enough available RAM on the host to
* change the VM allocated RAM
* @param ram the new total amount of RAM for the VM.
*
* @return true, if is suitable for vm
*/
public abstract boolean isSuitableForVm(Vm vm, int ram);
/**
* Gets the ram capacity.
*
* @return the ram
*/
public int getRam() {
return ram;
}
/**
* Sets the ram capacity.
*
* @param ram the ram to set
*/
protected void setRam(int ram) {
this.ram = ram;
}
/**
* Gets the amount of used RAM in the host.
*
* @return used ram
*
* @pre $none
* @post $none
*/
public int getUsedRam() {
return ram - availableRam;
}
/**
* Gets the available RAM in the host.
*
* @return th available ram
*
* @pre $none
* @post $none
*/
public int getAvailableRam() {
return availableRam;
}
/**
* Sets the available ram.
*
* @param availableRam the availableRam to set
*/
protected void setAvailableRam(int availableRam) {
this.availableRam = availableRam;
}
}