Performance improvement of the Logger. Ubiquitous string concatenation when the…

Performance improvement of the Logger. Ubiquitous string concatenation when the logger is off is now avoided.

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/Datacenter.java

@@ -383,12 +383,12 @@ public class Datacenter extends SimEntity {
 				status = getVmAllocationPolicy().getHost(vmId, userId).getVm(vmId,userId)
 						.getCloudletScheduler().getCloudletStatus(cloudletId);
 			} catch (Exception e) {
-				Log.printLine(getName() + ": Error in processing CloudSimTags.CLOUDLET_STATUS");
+				Log.printConcatLine(getName(), ": Error in processing CloudSimTags.CLOUDLET_STATUS");
 				Log.printLine(e.getMessage());
 				return;
 			}
 		} catch (Exception e) {
-			Log.printLine(getName() + ": Error in processing CloudSimTags.CLOUDLET_STATUS");
+			Log.printConcatLine(getName(), ": Error in processing CloudSimTags.CLOUDLET_STATUS");
 			Log.printLine(e.getMessage());
 			return;
 		}
@@ -412,7 +412,7 @@ public class Datacenter extends SimEntity {
 	 */
 	protected void processOtherEvent(SimEvent ev) {
 		if (ev == null) {
-			Log.printLine(getName() + ".processOtherEvent(): Error - an event is null.");
+			Log.printConcatLine(getName(), ".processOtherEvent(): Error - an event is null.");
 		}
 	}
 
@@ -560,12 +560,12 @@ public class Datacenter extends SimEntity {
 				userId = cl.getUserId();
 				vmId = cl.getVmId();
 			} catch (Exception e) {
-				Log.printLine(super.getName() + ": Error in processing Cloudlet");
+				Log.printConcatLine(super.getName(), ": Error in processing Cloudlet");
 				Log.printLine(e.getMessage());
 				return;
 			}
 		} catch (Exception e) {
-			Log.printLine(super.getName() + ": Error in processing a Cloudlet.");
+			Log.printConcatLine(super.getName(), ": Error in processing a Cloudlet.");
 			Log.printLine(e.getMessage());
 			return;
 		}
@@ -685,8 +685,8 @@ public class Datacenter extends SimEntity {
 			// checks whether this Cloudlet has finished or not
 			if (cl.isFinished()) {
 				String name = CloudSim.getEntityName(cl.getUserId());
-				Log.printLine(getName() + ": Warning - Cloudlet #" + cl.getCloudletId() + " owned by " + name
-						+ " is already completed/finished.");
+				Log.printConcatLine(getName(), ": Warning - Cloudlet #", cl.getCloudletId(), " owned by ", name,
+						" is already completed/finished.");
 				Log.printLine("Therefore, it is not being executed again");
 				Log.printLine();
 
@@ -1015,7 +1015,7 @@ public class Datacenter extends SimEntity {
 	 */
 	@Override
 	public void shutdownEntity() {
-		Log.printLine(getName() + " is shutting down...");
+		Log.printConcatLine(getName(), " is shutting down...");
 	}
 
 	/*
@@ -1024,7 +1024,7 @@ public class Datacenter extends SimEntity {
 	 */
 	@Override
 	public void startEntity() {
-		Log.printLine(getName() + " is starting...");
+		Log.printConcatLine(getName(), " is starting...");
 		// this resource should register to regional GIS.
 		// However, if not specified, then register to system GIS (the
 		// default CloudInformationService) entity.

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/DatacenterBroker.java

@@ -200,8 +200,8 @@ public class DatacenterBroker extends SimEntity {
 		setDatacenterIdsList(CloudSim.getCloudResourceList());
 		setDatacenterCharacteristicsList(new HashMap<Integer, DatacenterCharacteristics>());
 
-		Log.printLine(CloudSim.clock() + ": " + getName() + ": Cloud Resource List received with "
-				+ getDatacenterIdsList().size() + " resource(s)");
+		Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Cloud Resource List received with ",
+				getDatacenterIdsList().size(), " resource(s)");
 
 		for (Integer datacenterId : getDatacenterIdsList()) {
 			sendNow(datacenterId, CloudSimTags.RESOURCE_CHARACTERISTICS, getId());
@@ -224,12 +224,12 @@ public class DatacenterBroker extends SimEntity {
 		if (result == CloudSimTags.TRUE) {
 			getVmsToDatacentersMap().put(vmId, datacenterId);
 			getVmsCreatedList().add(VmList.getById(getVmList(), vmId));
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": VM #" + vmId
-					+ " has been created in Datacenter #" + datacenterId + ", Host #"
-					+ VmList.getById(getVmsCreatedList(), vmId).getHost().getId());
+			Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": VM #", vmId,
+					" has been created in Datacenter #", datacenterId, ", Host #",
+					VmList.getById(getVmsCreatedList(), vmId).getHost().getId());
 		} else {
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": Creation of VM #" + vmId
-					+ " failed in Datacenter #" + datacenterId);
+			Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Creation of VM #", vmId,
+					" failed in Datacenter #", datacenterId);
 		}
 
 		incrementVmsAcks();
@@ -270,11 +270,11 @@ public class DatacenterBroker extends SimEntity {
 	protected void processCloudletReturn(SimEvent ev) {
 		Cloudlet cloudlet = (Cloudlet) ev.getData();
 		getCloudletReceivedList().add(cloudlet);
-		Log.printLine(CloudSim.clock() + ": " + getName() + ": Cloudlet " + cloudlet.getCloudletId()
-				+ " received");
+		Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Cloudlet ", cloudlet.getCloudletId(),
+				" received");
 		cloudletsSubmitted--;
 		if (getCloudletList().size() == 0 && cloudletsSubmitted == 0) { // all cloudlets executed
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": All Cloudlets executed. Finishing...");
+			Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": All Cloudlets executed. Finishing...");
 			clearDatacenters();
 			finishExecution();
 		} else { // some cloudlets haven't finished yet
@@ -298,12 +298,11 @@ public class DatacenterBroker extends SimEntity {
 	 */
 	protected void processOtherEvent(SimEvent ev) {
 		if (ev == null) {
-			Log.printLine(getName() + ".processOtherEvent(): " + "Error - an event is null.");
+			Log.printConcatLine(getName(), ".processOtherEvent(): ", "Error - an event is null.");
 			return;
 		}
 
-		Log.printLine(getName() + ".processOtherEvent(): "
-				+ "Error - event unknown by this DatacenterBroker.");
+		Log.printConcatLine(getName(), ".processOtherEvent(): Error - event unknown by this DatacenterBroker.");
 	}
 
 	/**
@@ -348,15 +347,18 @@ public class DatacenterBroker extends SimEntity {
 				vm = getVmsCreatedList().get(vmIndex);
 			} else { // submit to the specific vm
 				vm = VmList.getById(getVmsCreatedList(), cloudlet.getVmId());
-				if (vm == null) { // vm was not created
-					Log.printLine(CloudSim.clock() + ": " + getName() + ": Postponing execution of cloudlet "
-							+ cloudlet.getCloudletId() + ": bount VM not available");
+				if (vm == null && !Log.isDisabled()) { // vm was not created
+					Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Postponing execution of cloudlet ",
+							cloudlet.getCloudletId(), ": bount VM not available");
 					continue;
 				}
 			}
 
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": Sending cloudlet "
-					+ cloudlet.getCloudletId() + " to VM #" + vm.getId());
+			if (!Log.isDisabled()) {
+			    Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Sending cloudlet ",
+					cloudlet.getCloudletId(), " to VM #", vm.getId());
+			}
+			
 			cloudlet.setVmId(vm.getId());
 			sendNow(getVmsToDatacentersMap().get(vm.getId()), CloudSimTags.CLOUDLET_SUBMIT, cloudlet);
 			cloudletsSubmitted++;
@@ -377,7 +379,7 @@ public class DatacenterBroker extends SimEntity {
 	 */
 	protected void clearDatacenters() {
 		for (Vm vm : getVmsCreatedList()) {
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": Destroying VM #" + vm.getId());
+			Log.printConcatLine(CloudSim.clock(), ": " + getName(), ": Destroying VM #", vm.getId());
 			sendNow(getVmsToDatacentersMap().get(vm.getId()), CloudSimTags.VM_DESTROY, vm);
 		}
 
@@ -400,7 +402,7 @@ public class DatacenterBroker extends SimEntity {
 	 */
 	@Override
 	public void shutdownEntity() {
-		Log.printLine(getName() + " is shutting down...");
+		Log.printConcatLine(getName(), " is shutting down...");
 	}
 
 	/*
@@ -409,7 +411,7 @@ public class DatacenterBroker extends SimEntity {
 	 */
 	@Override
 	public void startEntity() {
-		Log.printLine(getName() + " is starting...");
+		Log.printConcatLine(getName(), " is starting...");
 		schedule(getId(), 0, CloudSimTags.RESOURCE_CHARACTERISTICS_REQUEST);
 	}
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/HarddriveStorage.java

@@ -356,7 +356,7 @@ public class HarddriveStorage implements Storage {
 		// check first whether file name is valid or not
 		File obj = null;
 		if (fileName == null || fileName.length() == 0) {
-			Log.printLine(name + ".getFile(): Warning - invalid " + "file name.");
+			Log.printConcatLine(name, ".getFile(): Warning - invalid " + "file name.");
 			return obj;
 		}
 
@@ -450,13 +450,13 @@ public class HarddriveStorage implements Storage {
 	private boolean isFileValid(File file, String methodName) {
 
 		if (file == null) {
-			Log.printLine(name + "." + methodName + ": Warning - the given file is null.");
+			Log.printConcatLine(name, ".", methodName, ": Warning - the given file is null.");
 			return false;
 		}
 
 		String fileName = file.getName();
 		if (fileName == null || fileName.length() == 0) {
-			Log.printLine(name + "." + methodName + ": Warning - invalid file name.");
+			Log.printConcatLine(name, "." + methodName, ": Warning - invalid file name.");
 			return false;
 		}
 
@@ -482,7 +482,7 @@ public class HarddriveStorage implements Storage {
 
 		// check the capacity
 		if (file.getSize() + currentSize > capacity) {
-			Log.printLine(name + ".addFile(): Warning - not enough space" + " to store " + file.getName());
+			Log.printConcatLine(name, ".addFile(): Warning - not enough space to store ", file.getName());
 			return result;
 		}
 
@@ -512,7 +512,7 @@ public class HarddriveStorage implements Storage {
 	public double addFile(List<File> list) {
 		double result = 0.0;
 		if (list == null || list.isEmpty()) {
-			Log.printLine(name + ".addFile(): Warning - list is empty.");
+			Log.printConcatLine(name, ".addFile(): Warning - list is empty.");
 			return result;
 		}
 
@@ -607,7 +607,7 @@ public class HarddriveStorage implements Storage {
 	public boolean contains(String fileName) {
 		boolean result = false;
 		if (fileName == null || fileName.length() == 0) {
-			Log.printLine(name + ".contains(): Warning - invalid file name");
+			Log.printConcatLine(name, ".contains(): Warning - invalid file name");
 			return result;
 		}
 		// check each file in the list

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/Host.java

@@ -115,14 +115,14 @@ public class Host {
 
 		if (!getVmsMigratingIn().contains(vm)) {
 			if (getStorage() < vm.getSize()) {
-				Log.printLine("[VmScheduler.addMigratingInVm] Allocation of VM #" + vm.getId() + " to Host #"
-						+ getId() + " failed by storage");
+				Log.printConcatLine("[VmScheduler.addMigratingInVm] Allocation of VM #", vm.getId(), " to Host #",
+						getId(), " failed by storage");
 				System.exit(0);
 			}
 
 			if (!getRamProvisioner().allocateRamForVm(vm, vm.getCurrentRequestedRam())) {
-				Log.printLine("[VmScheduler.addMigratingInVm] Allocation of VM #" + vm.getId() + " to Host #"
-						+ getId() + " failed by RAM");
+				Log.printConcatLine("[VmScheduler.addMigratingInVm] Allocation of VM #", vm.getId(), " to Host #",
+						getId(), " failed by RAM");
 				System.exit(0);
 			}
 
@@ -202,27 +202,27 @@ public class Host {
 	 */
 	public boolean vmCreate(Vm vm) {
 		if (getStorage() < vm.getSize()) {
-			Log.printLine("[VmScheduler.vmCreate] Allocation of VM #" + vm.getId() + " to Host #" + getId()
-					+ " failed by storage");
+			Log.printConcatLine("[VmScheduler.vmCreate] Allocation of VM #", vm.getId(), " to Host #", getId(),
+					" failed by storage");
 			return false;
 		}
 
 		if (!getRamProvisioner().allocateRamForVm(vm, vm.getCurrentRequestedRam())) {
-			Log.printLine("[VmScheduler.vmCreate] Allocation of VM #" + vm.getId() + " to Host #" + getId()
-					+ " failed by RAM");
+			Log.printConcatLine("[VmScheduler.vmCreate] Allocation of VM #", vm.getId(), " to Host #", getId(),
+					" failed by RAM");
 			return false;
 		}
 
 		if (!getBwProvisioner().allocateBwForVm(vm, vm.getCurrentRequestedBw())) {
-			Log.printLine("[VmScheduler.vmCreate] Allocation of VM #" + vm.getId() + " to Host #" + getId()
-					+ " failed by BW");
+			Log.printConcatLine("[VmScheduler.vmCreate] Allocation of VM #", vm.getId(), " to Host #", getId(),
+					" failed by BW");
 			getRamProvisioner().deallocateRamForVm(vm);
 			return false;
 		}
 
 		if (!getVmScheduler().allocatePesForVm(vm, vm.getCurrentRequestedMips())) {
-			Log.printLine("[VmScheduler.vmCreate] Allocation of VM #" + vm.getId() + " to Host #" + getId()
-					+ " failed by MIPS");
+			Log.printConcatLine("[VmScheduler.vmCreate] Allocation of VM #", vm.getId(), " to Host #", getId(),
+					" failed by MIPS");
 			getRamProvisioner().deallocateRamForVm(vm);
 			getBwProvisioner().deallocateBwForVm(vm);
 			return false;

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/Log.java

@@ -29,6 +29,9 @@ public class Log {
 	/** The disable output flag. */
 	private static boolean disabled;
 	
+	/** Buffer to avoid creating new string builder upon every print. */
+	private static StringBuilder buffer = new StringBuilder();		    
+
 	/**
 	 * Prints the message.
 	 * 
@@ -75,6 +78,39 @@ public class Log {
 		}
 	}
 
+
+	/**
+	 * Prints the concatenated text representation of the arguements.
+	 * 
+	 * @param messages the messages to print
+	 */
+	public static void printConcat(Object... messages) {
+		if (!isDisabled()) {
+			buffer.setLength(0); // Clear the buffer		    
+			for(int i = 0 ; i < messages.length ; i ++) {
+				buffer.append(String.valueOf(messages[i]));
+			}
+			print(buffer);
+		}
+	}
+	
+	/**
+	 * Prints the concatenated text representation of the arguements and a new line.
+	 * 
+	 * @param messages the messages to print
+	 */
+	public static void printConcatLine(Object... messages) {
+		if (!isDisabled()) {
+			buffer.setLength(0); // Clear the buffer		    
+			for(int i = 0 ; i < messages.length ; i ++) {
+				buffer.append(String.valueOf(messages[i]));
+			}
+			printLine(buffer);
+		}
+	}
+
+	
+	
 	/**
 	 * Prints the line passed as a non-String object.
 	 * 
@@ -86,6 +122,8 @@ public class Log {
 	    }
 	}
 
+	
+	
 	/**
 	 * Prints a string formated as in String.format().
 	 * 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/NetworkTopology.java

@@ -57,7 +57,7 @@ public class NetworkTopology {
 	 * @post $none
 	 */
 	public static void buildNetworkTopology(String fileName) {
-		Log.printLine("Topology file: " + fileName);
+		Log.printConcatLine("Topology file: ", fileName);
 
 		// try to find the file
 		GraphReaderBrite reader = new GraphReaderBrite();
@@ -178,15 +178,15 @@ public class NetworkTopology {
 					if (!map.containsValue(briteID)) { // this BRITE node was already mapped?
 						map.put(cloudSimEntityID, briteID);
 					} else {
-						Log.printLine("Error in network mapping. BRITE node " + briteID + " already in use.");
+						Log.printConcatLine("Error in network mapping. BRITE node ", briteID, " already in use.");
 					}
 				} else {
-					Log.printLine("Error in network mapping. CloudSim entity " + cloudSimEntityID
-							+ " already mapped.");
+					Log.printConcatLine("Error in network mapping. CloudSim entity ", cloudSimEntityID,
+							" already mapped.");
 				}
 			} catch (Exception e) {
-				Log.printLine("Error in network mapping. CloudSim node " + cloudSimEntityID
-						+ " not mapped to BRITE node " + briteID + ".");
+				Log.printConcatLine("Error in network mapping. CloudSim node ", cloudSimEntityID,
+						" not mapped to BRITE node ", briteID, ".");
 			}
 		}
 	}
@@ -203,7 +203,7 @@ public class NetworkTopology {
 			try {
 				map.remove(cloudSimEntityID);
 			} catch (Exception e) {
-				Log.printLine("Error in network unmapping. CloudSim node: " + cloudSimEntityID);
+				Log.printConcatLine("Error in network unmapping. CloudSim node: ", cloudSimEntityID);
 			}
 		}
 	}

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/SanStorage.java

@@ -120,7 +120,7 @@ public class SanStorage extends HarddriveStorage {
 	public double addFile(List<File> list) {
 		double result = 0.0;
 		if (list == null || list.size() == 0) {
-			Log.printLine(getName() + ".addFile(): Warning - list is empty.");
+			Log.printConcatLine(getName(), ".addFile(): Warning - list is empty.");
 			return result;
 		}
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/VmSchedulerTimeShared.java

@@ -149,7 +149,7 @@ public class VmSchedulerTimeShared extends VmScheduler {
 							break;
 						}
 						if (!peIterator.hasNext()) {
-							Log.printLine("There is no enough MIPS (" + mips + ") to accommodate VM " + vmUid);
+							Log.printConcatLine("There is no enough MIPS (", mips, ") to accommodate VM ", vmUid);
 							// System.exit(0);
 						}
 						pe = peIterator.next();

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/core/CloudInformationService.java

@@ -237,8 +237,8 @@ public class CloudInformationService extends SimEntity {
 	 */
 	protected void processOtherEvent(SimEvent ev) {
 		if (ev == null) {
-			Log.printLine("CloudInformationService.processOtherEvent(): "
-					+ "Unable to handle a request since the event is null.");
+			Log.printConcatLine("CloudInformationService.processOtherEvent(): ",
+					"Unable to handle a request since the event is null.");
 			return;
 		}
 
@@ -294,7 +294,7 @@ public class CloudInformationService extends SimEntity {
 	 * @post $none
 	 */
 	private void notifyAllEntity() {
-		Log.printLine(super.getName() + ": Notify all CloudSim entities for shutting down.");
+		Log.printConcatLine(super.getName(), ": Notify all CloudSim entities for shutting down.");
 
 		signalShutdown(resList);
 		signalShutdown(gisList);

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/core/CloudSim.java

@@ -183,7 +183,7 @@ public class CloudSim {
 	 * @post $none
 	 */
 	public static double startSimulation() throws NullPointerException {
-		Log.printLine("Starting CloudSim version " + CLOUDSIM_VERSION_STRING);
+		Log.printConcatLine("Starting CloudSim version ", CLOUDSIM_VERSION_STRING);
 		try {
 			double clock = run();
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/core/SimEntity.java

@@ -532,7 +532,7 @@ public abstract class SimEntity implements Cloneable {
 		}
 
 		if (entityId < 0) {
-			Log.printLine(getName() + ".send(): Error - " + "invalid entity id " + entityId);
+			Log.printConcatLine(getName(), ".send(): Error - " + "invalid entity id ", entityId);
 			return;
 		}
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/lists/PeList.java

@@ -205,7 +205,7 @@ public class PeList {
 			status = "WORKING";
 		}
 
-		Log.printLine(resName + " - Machine: " + hostId + " is " + status);
+		Log.printConcatLine(resName, " - Machine: ", hostId, " is ", status);
 
 		setStatusFailed(peList, failed);
 	}

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/network/datacenter/NetDatacenterBroker.java

@@ -223,8 +223,8 @@ public class NetDatacenterBroker extends SimEntity {
 		setDatacenterIdsList(CloudSim.getCloudResourceList());
 		setDatacenterCharacteristicsList(new HashMap<Integer, DatacenterCharacteristics>());
 
-		Log.printLine(CloudSim.clock() + ": " + getName() + ": Cloud Resource List received with "
-				+ getDatacenterIdsList().size() + " resource(s)");
+		Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Cloud Resource List received with ",
+				getDatacenterIdsList().size(), " resource(s)");
 
 		for (Integer datacenterId : getDatacenterIdsList()) {
 			sendNow(datacenterId, CloudSimTags.RESOURCE_CHARACTERISTICS, getId());
@@ -254,7 +254,7 @@ public class NetDatacenterBroker extends SimEntity {
 		cloudletsSubmitted--;
 		// all cloudlets executed
 		if (getCloudletList().size() == 0 && cloudletsSubmitted == 0 && NetworkConstants.iteration > 10) {
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": All Cloudlets executed. Finishing...");
+			Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": All Cloudlets executed. Finishing...");
 			clearDatacenters();
 			finishExecution();
 		} else { // some cloudlets haven't finished yet
@@ -279,12 +279,12 @@ public class NetDatacenterBroker extends SimEntity {
 	 */
 	protected void processOtherEvent(SimEvent ev) {
 		if (ev == null) {
-			Log.printLine(getName() + ".processOtherEvent(): " + "Error - an event is null.");
+			Log.printConcatLine(getName(), ".processOtherEvent(): Error - an event is null.");
 			return;
 		}
 
-		Log.printLine(getName() + ".processOtherEvent(): "
-				+ "Error - event unknown by this DatacenterBroker.");
+		Log.printConcatLine(getName(), ".processOtherEvent(): ",
+				"Error - event unknown by this DatacenterBroker.");
 	}
 
 	/**
@@ -402,7 +402,7 @@ public class NetDatacenterBroker extends SimEntity {
 	 */
 	protected void clearDatacenters() {
 		for (Vm vm : getVmsCreatedList()) {
-			Log.printLine(CloudSim.clock() + ": " + getName() + ": Destroying VM #" + vm.getId());
+			Log.printConcatLine(CloudSim.clock(), ": ", getName(), ": Destroying VM #", vm.getId());
 			sendNow(getVmsToDatacentersMap().get(vm.getId()), CloudSimTags.VM_DESTROY, vm);
 		}
 
@@ -425,7 +425,7 @@ public class NetDatacenterBroker extends SimEntity {
 	 */
 	@Override
 	public void shutdownEntity() {
-		Log.printLine(getName() + " is shutting down...");
+		Log.printConcatLine(getName(), " is shutting down...");
 	}
 
 	/*
@@ -434,7 +434,7 @@ public class NetDatacenterBroker extends SimEntity {
 	 */
 	@Override
 	public void startEntity() {
-		Log.printLine(getName() + " is starting...");
+		Log.printConcatLine(getName(), " is starting...");
 		schedule(getId(), 0, CloudSimTags.RESOURCE_CHARACTERISTICS_REQUEST);
 	}
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/network/datacenter/NetworkDatacenter.java

@@ -147,8 +147,8 @@ public class NetworkDatacenter extends Datacenter {
 			// checks whether this Cloudlet has finished or not
 			if (cl.isFinished()) {
 				String name = CloudSim.getEntityName(cl.getUserId());
-				Log.printLine(getName() + ": Warning - Cloudlet #" + cl.getCloudletId() + " owned by " + name
-						+ " is already completed/finished.");
+				Log.printConcatLine(getName(), ": Warning - Cloudlet #", cl.getCloudletId(), " owned by ", name,
+						" is already completed/finished.");
 				Log.printLine("Therefore, it is not being executed again");
 				Log.printLine();
 

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/network/datacenter/Switch.java

@@ -80,7 +80,7 @@ public class Switch extends SimEntity {
 
 	@Override
 	public void startEntity() {
-		Log.printLine(getName() + " is starting...");
+		Log.printConcatLine(getName(), " is starting...");
 		schedule(getId(), 0, CloudSimTags.RESOURCE_CHARACTERISTICS_REQUEST);
 	}
 
@@ -380,7 +380,7 @@ public class Switch extends SimEntity {
 
 	@Override
 	public void shutdownEntity() {
-		Log.printLine(getName() + " is shutting down...");
+		Log.printConcatLine(getName(), " is shutting down...");
 	}
 
 }

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/power/PowerVmAllocationPolicyMigrationAbstract.java

@@ -156,7 +156,7 @@ public abstract class PowerVmAllocationPolicyMigrationAbstract extends PowerVmAl
 				break;
 			}
 
-			Log.printLine("Under-utilized host: host #" + underUtilizedHost.getId() + "\n");
+			Log.printConcatLine("Under-utilized host: host #", underUtilizedHost.getId(), "\n");
 
 			excludedHostsForFindingUnderUtilizedHost.add(underUtilizedHost);
 			excludedHostsForFindingNewVmPlacement.add(underUtilizedHost);
@@ -196,7 +196,7 @@ public abstract class PowerVmAllocationPolicyMigrationAbstract extends PowerVmAl
 		if (!Log.isDisabled()) {
 			Log.printLine("Over-utilized hosts:");
 			for (PowerHostUtilizationHistory host : overUtilizedHosts) {
-				Log.printLine("Host #" + host.getId());
+				Log.printConcatLine("Host #", host.getId());
 			}
 			Log.printLine();
 		}
@@ -299,7 +299,7 @@ public abstract class PowerVmAllocationPolicyMigrationAbstract extends PowerVmAl
 			PowerHost allocatedHost = findHostForVm(vm, excludedHosts);
 			if (allocatedHost != null) {
 				allocatedHost.vmCreate(vm);
-				Log.printLine("VM #" + vm.getId() + " allocated to host #" + allocatedHost.getId());
+				Log.printConcatLine("VM #", vm.getId(), " allocated to host #", allocatedHost.getId());
 
 				Map<String, Object> migrate = new HashMap<String, Object>();
 				migrate.put("vm", vm);
@@ -326,7 +326,7 @@ public abstract class PowerVmAllocationPolicyMigrationAbstract extends PowerVmAl
 			PowerHost allocatedHost = findHostForVm(vm, excludedHosts);
 			if (allocatedHost != null) {
 				allocatedHost.vmCreate(vm);
-				Log.printLine("VM #" + vm.getId() + " allocated to host #" + allocatedHost.getId());
+				Log.printConcatLine("VM #", vm.getId(), " allocated to host #", allocatedHost.getId());
 
 				Map<String, Object> migrate = new HashMap<String, Object>();
 				migrate.put("vm", vm);
@@ -519,7 +519,7 @@ public abstract class PowerVmAllocationPolicyMigrationAbstract extends PowerVmAl
 			Vm vm = (Vm) map.get("vm");
 			PowerHost host = (PowerHost) map.get("host");
 			if (!host.vmCreate(vm)) {
-				Log.printLine("Couldn't restore VM #" + vm.getId() + " on host #" + host.getId());
+				Log.printConcatLine("Couldn't restore VM #", vm.getId(), " on host #", host.getId());
 				System.exit(0);
 			}
 			getVmTable().put(vm.getUid(), host);

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/power/PowerVmAllocationPolicyMigrationInterQuartileRange.java

@@ -119,8 +119,8 @@ public class PowerVmAllocationPolicyMigrationInterQuartileRange extends
 	 */
 	protected void setSafetyParameter(double safetyParameter) {
 		if (safetyParameter < 0) {
-			Log.printLine("The safety parameter cannot be less than zero. The passed value is: "
-					+ safetyParameter);
+			Log.printConcatLine("The safety parameter cannot be less than zero. The passed value is: ",
+					safetyParameter);
 			System.exit(0);
 		}
 		this.safetyParameter = safetyParameter;

modules/cloudsim/src/main/java/org/cloudbus/cloudsim/power/PowerVmAllocationPolicyMigrationMedianAbsoluteDeviation.java

@@ -119,8 +119,8 @@ public class PowerVmAllocationPolicyMigrationMedianAbsoluteDeviation extends
 	 */
 	protected void setSafetyParameter(double safetyParameter) {
 		if (safetyParameter < 0) {
-			Log.printLine("The safety parameter cannot be less than zero. The passed value is: "
-					+ safetyParameter);
+			Log.printConcatLine("The safety parameter cannot be less than zero. The passed value is: ",
+					safetyParameter);
 			System.exit(0);
 		}
 		this.safetyParameter = safetyParameter;