Replace Data Value with Object

Replace Data Value with Object:

CloudDataCenterBroker.java

Replace primitive fields like cloudletsSubmitted, vmsRequested, vmsAcks, vmsDestroyed with dedicated classes or objects

Benefits: Encapsulation or additional behavior.

// Class for CloudletSubmission
class CloudletSubmission {
    private int count;

    public CloudletSubmission() {
        count = 0;
    }

    public void increment() {
        count++;
    }

    public int getCount() {
        return count;
    }
}

// Class for VmRequest
class VmRequest {
    private int count;

    public VmRequest() {
        count = 0;
    }

    public void increment() {
        count++;
    }

    public int getCount() {
        return count;
    }
}

Inline Method

Problem Description The getSeekTime(in size) method is a simple method that is used as a getter twice.

Benefits Consider writing the expression on a single line to avoid using the temporary variable seekTime.

public HarddriveStorage(double capacity) throws ParameterException {
        obj = fileList.get(index);
        double transferTime = getTransferTime(obj.getSize());

        obj.setTransactionTime(getSeekTime(size)+transferTime);

        return obj;
    }

Move method

CloudSim Host.java

Issue Description

Methods related to VM migration can be moved to a dedicated VmMigrationManager class.

Benefits: Helps with the single responsibility principle by balancing the load of the main class into helper classes.

public class MigratingVms{
    public void addMigratingInVm(Vm vm){}
    public void removeMigratingVm(Vm vm){}
    public void reallocateMigratingInVms(){}

}

Extract method

Problem Description: We apply Extract method because it breaks down the long and complex ‘main’ into smaller methods like initializeCloudSim, createAndSubmitVm, and createAndSubmitCloudlet, making the program flow clearer and easier to follow.

Benefits:

Maintainability: Allows modifying specific parts of the configuration (like VMs or Cloudlets) without affecting the rest of the code, simplifying management and updating.

Modularity: Facilitates reusing methods in other contexts or tests, reducing code duplication.

Debugging: Helps identify and fix bugs more easily by isolating logic into separate methods.

Previous Design:

From line 51 to 157 the main method. More than 100 lines. Paragraph locked by Anonymous User

public class CloudSimExample1 {

    private static List<Vm> vmlist;
    private static List<Cloudlet> cloudletList;

    public static void main(String[] args) {
        Log.printLine("Starting CloudSimExample1...");

        try {
            initializeCloudSim();
            Datacenter datacenter0 = createDatacenter("Datacenter_0");
            DatacenterBroker broker = createBroker();
            createAndSubmitVm(broker);
            createAndSubmitCloudlet(broker);
            runSimulation();
            printResults(broker);

            Log.printLine("CloudSimExample1 finished!");
        } catch (Exception e) {
            e.printStackTrace();
            Log.printLine("Unwanted errors happened");
        }
    }

    private static void initializeCloudSim() {
        int num_user = 1; // number of cloud users
        Calendar calendar = Calendar.getInstance(); // Calendar whose fields have been initialized with the current date and time.
        boolean trace_flag = false; // trace events

        CloudSim.init(num_user, calendar, trace_flag);
    }

    private static Datacenter createDatacenter(String name) {
        // Create and return a Datacenter instance
        return new Datacenter(name, ...); // Provide necessary parameters for Datacenter creation
    }

    private static DatacenterBroker createBroker() {
        // Create and return a DatacenterBroker instance
        return new DatacenterBroker("Broker");
    }

    private static void createAndSubmitVm(DatacenterBroker broker) {
        vmlist = new ArrayList<>();

        int vmid = 0;
        int mips = 1000;
        long size = 10000; // image size (MB)
        int ram = 512; // vm memory (MB)
        long bw = 1000;
        int pesNumber = 1; // number of cpus
        String vmm = "Xen"; // VMM name

        Vm vm = new Vm(vmid, broker.getId(), mips, pesNumber, ram, bw, size, vmm, new CloudletSchedulerTimeShared());
        vmlist.add(vm);

        broker.submitVmList(vmlist);
    }

    private static void createAndSubmitCloudlet(DatacenterBroker broker) {
        cloudletList = new ArrayList<>();

        int id = 0;
        long length = 400000;
        long fileSize = 300;
        long outputSize = 300;
        UtilizationModel utilizationModel = new UtilizationModelFull();

        Cloudlet cloudlet = new Cloudlet(id, length, 1, fileSize, outputSize, utilizationModel, utilizationModel, utilizationModel);
        cloudlet.setUserId(broker.getId());
        cloudlet.setVmId(0); // Assuming VM id is 0

        cloudletList.add(cloudlet);
        broker.submitCloudletList(cloudletList);
    }

    private static void runSimulation() {
        CloudSim.startSimulation();
        CloudSim.stopSimulation();
    }

    private static void printResults(DatacenterBroker broker) {
        List<Cloudlet> newList = broker.getCloudletReceivedList();
        printCloudletList(newList);
    }

    private static void printCloudletList(List<Cloudlet> list) {
        // Print the Cloudlet list
        for (Cloudlet cloudlet : list) {
            Log.printLine("Cloudlet ID: " + cloudlet.getCloudletId() +
                    " Status: " + cloudlet.getStatus() +
                    " Result: " + cloudlet.getActualCPUTime());
        }
    }
}

Extract class

Problem Description: The constructor of the cloudlet class has more than three parameters in the constructor thus violating long parameter list. The solution is as follows: Introduce a parameter object. Create a dedicated class to encapsulate the related parameters. Pass an instance of this class as a single parameter to the method.

Benefits: Improved readability, maintainability, and testability.

class CloudletNumParam{
    int id;
    int length;
    int pesNumber;

    CloudletNumParam(int id, int length, int pesNumber){
        this.id = id;
        this.length = length;
        this.pesNumber = pesNumber;
    }
}

class CloudletSizeParam{
    int fileSize;
    int outputSize;

    CloudletSizeParam(int fileSize, int outputSize){
        this.fileSize = fileSize;
        this.outputSize = outputSize;
    }
}

class CloudletUtilizationModelParam{
    UtilizationModel um1;
    UtilizationModel um2;
    UtilizationModel um3;

    CloudletUtilizationModel(UtilizationModel um1, UtilizationModel um2, UtilizationModel um3){
        this.um1 = um1;
        this.um2 = um2;
        this.um3 = um3;
    }

}

class Cloudlet{
    int id;
    int length;
    int pesNumber;
    int fileSize;
    int outputSize;
    UtilizationModel um1;
    UtilizationModel um2;
    UtilizationModel um3;

    Cloudlet(CloudletNumParam cnp, CloudletSizeParam csp, CloudletUtilizationModelParam cump){
        this.id = cnp.id;
        this.length = cnp.length;
        this.pesNumber = cnp.pesNumber;
        this.fileSize = csp.fileSize;
        this.outputSize = csp.outputSize;
        this.um1 = cump.um1;
        this.um2 = cump.um2;
        this.um3 = cump.um3;

    }
}

class UtilizationModel{}

Cloudlet cloudlet = new Cloudlet(new CloudletNumParam(1, 2, 3), new CloudletSizeParam(4, 5), new CloudletUtilizationModelParam(new UtilizationModel(), new UtilizationModel()));

Cloudslab / cloudsim