package org.cloudbus.cloudsim.examples;

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.LinkedList;
import java.util.List;

import org.cloudbus.cloudsim.Cloudlet;
import org.cloudbus.cloudsim.CloudletSchedulerTimeShared;
import org.cloudbus.cloudsim.Datacenter;
import org.cloudbus.cloudsim.DatacenterBroker;
import org.cloudbus.cloudsim.DatacenterCharacteristics;
import org.cloudbus.cloudsim.Host;
import org.cloudbus.cloudsim.Log;
import org.cloudbus.cloudsim.Pe;
import org.cloudbus.cloudsim.Storage;
import org.cloudbus.cloudsim.UtilizationModel;
import org.cloudbus.cloudsim.UtilizationModelFull;
import org.cloudbus.cloudsim.Vm;
import org.cloudbus.cloudsim.VmAllocationPolicySimple;
import org.cloudbus.cloudsim.VmSchedulerTimeShared;
import org.cloudbus.cloudsim.core.CloudSim;
import org.cloudbus.cloudsim.provisioners.BwProvisionerSimple;
import org.cloudbus.cloudsim.provisioners.PeProvisionerSimple;
import org.cloudbus.cloudsim.provisioners.RamProvisionerSimple;

/**
 * A simple example showing how to create a datacenter with one host and run one
 * cloudlet on it.
 */
public class CloudSimExample1 {

	/** The cloudlet list. */
	private static List<Cloudlet> cloudletList;

	/** The vmlist. */
	private static List<Vm> vmlist;

	/**
	 * Creates main() to run this example.
	 *
	 * @param args the args
	 */
	@SuppressWarnings("unused")
	public static void main(String[] args) {

		Log.printLine("Starting CloudSimExample1...");

		try {
			// First step: Initialize the CloudSim package. It should be called
			// before creating any entities.
			int num_user = 1; // number of cloud users
			Calendar calendar = Calendar.getInstance();
			System.out.println("Time is: "+ calendar.getTime());
			boolean trace_flag = false; // mean trace events

			// Initialize the CloudSim library
			CloudSim.init(num_user, calendar, trace_flag);

			// Second step: Create Datacenters
			// Datacenters are the resource providers in CloudSim. We need at
			// list one of them to run a CloudSim simulation
			Datacenter datacenter0 = createDatacenter("Datacenter_0");

			// Third step: Create Broker
			DatacenterBroker broker = createBroker();
			int brokerId = broker.getId();

			// Fourth step: Create one virtual machine
			vmlist = new ArrayList<Vm>();

			// VM description
			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

			// create VM
			Vm vm = new Vm(vmid, brokerId, mips, pesNumber, ram, bw, size, vmm, new CloudletSchedulerTimeShared());

			// add the VM to the vmList
			vmlist.add(vm);

			// submit vm list to the broker
			broker.submitVmList(vmlist);

			// Fifth step: Create one Cloudlet
			cloudletList = new ArrayList<Cloudlet>();

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

			Cloudlet cloudlet = new Cloudlet(id, length, pesNumber, fileSize, outputSize, utilizationModel, utilizationModel, utilizationModel);
			cloudlet.setUserId(brokerId);
			cloudlet.setVmId(vmid);

			// add the cloudlet to the list
			cloudletList.add(cloudlet);

			// submit cloudlet list to the broker
			broker.submitCloudletList(cloudletList);
			
			/*double responseTime, executionTime;
			
			responseTime=cloudlet.getFinishTime()-cloudlet.getSubmissionTime();
			executionTime=cloudlet.getFinishTime()-cloudlet.getExecStartTime();
			
			System.out.println("Response time is: "+ responseTime);
			System.out.println("Execution time is: "+ executionTime);*/
			
			

			// Sixth step: Starts the simulation
			CloudSim.startSimulation();

			CloudSim.stopSimulation();

			//Final step: Print results when simulation is over
			List<Cloudlet> newList = broker.getCloudletReceivedList();
			printCloudletList(newList);

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

	/**
	 * Creates the datacenter.
	 *
	 * @param name the name
	 *
	 * @return the datacenter
	 */
	private static Datacenter createDatacenter(String name) {

		// Here are the steps needed to create a PowerDatacenter:
		// 1. We need to create a list to store
		// our machine
		List<Host> hostList = new ArrayList<Host>();

		// 2. A Machine contains one or more PEs or CPUs/Cores.
		// In this example, it will have only one core.
		List<Pe> peList = new ArrayList<Pe>();

		int mips = 1000;

		// 3. Create PEs and add these into a list.
		peList.add(new Pe(0, new PeProvisionerSimple(mips))); // need to store Pe id and MIPS Rating

		// 4. Create Host with its id and list of PEs and add them to the list
		// of machines
		int hostId = 0;
		int ram = 2048; // host memory (MB)
		long storage = 1000000; // host storage
		int bw = 10000;

		hostList.add(
			new Host(
				hostId,
				new RamProvisionerSimple(ram),
				new BwProvisionerSimple(bw),
				storage,
				peList,
				new VmSchedulerTimeShared(peList)
			)
		); // This is our machine

		// 5. Create a DatacenterCharacteristics object that stores the
		// properties of a data center: architecture, OS, list of
		// Machines, allocation policy: time- or space-shared, time zone
		// and its price (G$/Pe time unit).
		String arch = "x86"; // system architecture
		String os = "Linux"; // operating system
		String vmm = "Xen";
		double time_zone = 10.0; // time zone this resource located
		double cost = 3.0; // the cost of using processing in this resource
		double costPerMem = 0.05; // the cost of using memory in this resource
		double costPerStorage = 0.001; // the cost of using storage in this
										// resource
		double costPerBw = 0.0; // the cost of using bw in this resource
		LinkedList<Storage> storageList = new LinkedList<Storage>(); // we are not adding SAN
													// devices by now

		DatacenterCharacteristics characteristics = new DatacenterCharacteristics(
				arch, os, vmm, hostList, time_zone, cost, costPerMem,
				costPerStorage, costPerBw);

		// 6. Finally, we need to create a PowerDatacenter object.
		Datacenter datacenter = null;
		try {
			datacenter = new Datacenter(name, characteristics, new VmAllocationPolicySimple(hostList), storageList, 0);
		} catch (Exception e) {
			e.printStackTrace();
		}

		return datacenter;
	}

	// We strongly encourage users to develop their own broker policies, to
	// submit vms and cloudlets according
	// to the specific rules of the simulated scenario
	/**
	 * Creates the broker.
	 *
	 * @return the datacenter broker
	 */
	private static DatacenterBroker createBroker() {
		DatacenterBroker broker = null;
		try {
			broker = new DatacenterBroker("Broker");
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return broker;
	}

	/**
	 * Prints the Cloudlet objects.
	 *
	 * @param list list of Cloudlets
	 */
	private static void printCloudletList(List<Cloudlet> list) {
		int size = list.size();
		Cloudlet cloudlet;

		String indent = "    ";
		Log.printLine();
		Log.printLine("========== OUTPUT ==========");
		Log.printLine("Cloudlet ID" + indent + "STATUS" + indent
				+ "Data center ID" + indent + "VM ID" + indent + "Time" + indent
				+ "Start Time" + indent + "Finish Time");

		
		double responseTime, executionTime;
		
		
		
		
		
		DecimalFormat dft = new DecimalFormat("###.##");
		for (int i = 0; i < size; i++) {
			cloudlet = list.get(i);
			Log.print(indent + cloudlet.getCloudletId() + indent + indent);			
			

			if (cloudlet.getCloudletStatus() == Cloudlet.SUCCESS) {
				Log.print("SUCCESS");

				Log.printLine(indent + indent + cloudlet.getResourceId()
						+ indent + indent + indent + cloudlet.getVmId()
						+ indent + indent
						+ dft.format(cloudlet.getActualCPUTime()) + indent
						+ indent + dft.format(cloudlet.getExecStartTime())
						+ indent + indent
						+ dft.format(cloudlet.getFinishTime()));
				
				
				responseTime=cloudlet.getFinishTime()-cloudlet.getSubmissionTime();
				executionTime=cloudlet.getFinishTime()-cloudlet.getExecStartTime();
				
				System.out.println("Response time is: "+ responseTime);
				System.out.println("Execution time is: "+ executionTime);
			}
		}
	}

}
 

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Taking inputs (stdin)

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About Java

Java is a very popular general-purpose programming language, it is class-based and object-oriented. Java was developed by James Gosling at Sun Microsystems ( later acquired by Oracle) the initial release of Java was in 1995. Java 17 is the latest long-term supported version (LTS). As of today, Java is the world's number one server programming language with a 12 million developer community, 5 million students studying worldwide and it's #1 choice for the cloud development.

Syntax help

Variables

short x = 999; 			// -32768 to 32767
int   x = 99999; 		// -2147483648 to 2147483647
long  x = 99999999999L; // -9223372036854775808 to 9223372036854775807

float x = 1.2;
double x = 99.99d;

byte x = 99; // -128 to 127
char x = 'A';
boolean x = true;

Loops

1. If Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
  // code
} else {
  // code
}

Example:

int i = 10;
if(i % 2 == 0) {
  System.out.println("i is even number");
} else {
  System.out.println("i is odd number");
}

2. Switch:

Switch is an alternative to If-Else-If ladder and to select one among many blocks of code.

switch(<conditional-expression>) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 //code to be executed when all the above cases are not matched;    
} 

3. For:

For loop is used to iterate a set of statements based on a condition. Usually for loop is preferred when number of iterations is known in advance.

for(Initialization; Condition; Increment/decrement){  
    //code  
} 

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(<condition>){  
 // code 
}  

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (<condition>); 

Classes and Objects

Class is the blueprint of an object, which is also referred as user-defined data type with variables and functions. Object is a basic unit in OOP, and is an instance of the class.

How to create a Class:

class keyword is required to create a class.

Example:

class Mobile {
    public:    // access specifier which specifies that accessibility of class members 
    string name; // string variable (attribute)
    int price; // int variable (attribute)
};

How to create a Object:

Mobile m1 = new Mobile();

How to define methods in a class:

public class Greeting {
    static void hello() {
        System.out.println("Hello.. Happy learning!");
    }

    public static void main(String[] args) {
        hello();
    }
}

Collections

Collection is a group of objects which can be represented as a single unit. Collections are introduced to bring a unified common interface to all the objects.

Collection Framework was introduced since JDK 1.2 which is used to represent and manage Collections and it contains:

  1. Interfaces
  2. Classes
  3. Algorithms

This framework also defines map interfaces and several classes in addition to Collections.

Advantages:

  • High performance
  • Reduces developer's effort
  • Unified architecture which has common methods for all objects.
CollectionDescription
SetSet is a collection of elements which can not contain duplicate values. Set is implemented in HashSets, LinkedHashSets, TreeSet etc
ListList is a ordered collection of elements which can have duplicates. Lists are classified into ArrayList, LinkedList, Vectors
QueueFIFO approach, while instantiating Queue interface you can either choose LinkedList or PriorityQueue.
DequeDeque(Double Ended Queue) is used to add or remove elements from both the ends of the Queue(both head and tail)
MapMap contains key-values pairs which don't have any duplicates. Map is implemented in HashMap, TreeMap etc.