diff --git a/src/org/gcube/vremanagement/vremodeler/impl/util/XMLUtil.java b/src/org/gcube/vremanagement/vremodeler/impl/util/XMLUtil.java
index d9710e7..8cc39ae 100644
--- a/src/org/gcube/vremanagement/vremodeler/impl/util/XMLUtil.java
+++ b/src/org/gcube/vremanagement/vremodeler/impl/util/XMLUtil.java
@@ -1,20 +1,31 @@
 package org.gcube.vremanagement.vremodeler.impl.util;
 
+import java.io.StringWriter;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.Enumeration;
 import java.util.Hashtable;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
 import org.gcube.common.core.utils.logging.GCUBELog;
 import org.gcube.vremanagement.vremodeler.db.DBInterface;
 import org.gcube.vremanagement.vremodeler.impl.ModelerService;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+
 
 
 
 /**
  * 
- * @author lucio
+ * @author Lucio Lelii
  *
  */
 public class XMLUtil {
@@ -25,95 +36,97 @@ public class XMLUtil {
 	/**
 	 * it creates the XML output for VDLGenerator
 	 * 
-	 * @param res
-	 * @return String
+	 * @param res the result set of the query on database
+	 * @return String the XML
 	 */
 	public static String PrepareCollectionXML(ResultSet res, ArrayList<String> relatedCollection){
-		StringBuilder temp= new StringBuilder();
-		String selectedString="false";
-		temp.append("<ResultSet>");
+		
+		Document doc= null;
+        try {
+        	doc= DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+		} catch (ParserConfigurationException e1) {
+			logger.error("Error creating XML Message");
+			e1.printStackTrace();
+		}
+		
+		Element root= doc.createElement("ResultSet");
+				
 		try{
 			while (res.next()){
-				
-				    selectedString= relatedCollection.contains(res.getString("ID")) ? "true" : "false";
-					temp.append("<Collection><ID>");
-					temp.append(res.getString(1));
-					temp.append("</ID><Name>");
-					temp.append(res.getString(2));
-					temp.append("</Name><Info><Description>");
-					temp.append(res.getString(3));
-					temp.append("</Description><NumberOfMembers>");
-					temp.append(res.getString(4));
-					temp.append("</NumberOfMembers><CreationTime>");
-					temp.append(res.getString(5));
-					temp.append("</CreationTime><LastUpdateTime>");
-					temp.append(res.getString(6));
-					temp.append("</LastUpdateTime></Info><Selected>");
-					temp.append(selectedString);
-					temp.append("</Selected></Collection>");
+					Element collection = addElements(doc, "Collection", 
+							new Element[]{createTextElement(doc, "ID", res.getString(1)), 
+										  createTextElement(doc, "Name", res.getString(2)), 
+										  addElements(doc, "Info", 
+												  new Element[]{
+												     createTextElement(doc, "Description",res.getString(3)), 
+												     createTextElement(doc, "NumberOfMembers",res.getString(4)), 
+												     createTextElement(doc, "CreationTime",res.getString(5)), 
+												     createTextElement(doc, "LastUpdateTime",res.getString(6))}), 
+										  createTextElement(doc, "Selected",relatedCollection.contains(res.getString(1)) ? "true" : "false") });									
+					root.appendChild(collection);
 			}
 		}catch(SQLException e){
 			logger.error("database error "+e.getMessage());
 			e.printStackTrace();
 		}
-		temp.append("</ResultSet>");
+		doc.appendChild(root);
 		//logger.debug("VDLMODEL: request collection XML: "+temp);
-		return temp.toString();
+		return docToString(doc);
 	}
 	
 	
+	
+	@SuppressWarnings("unchecked")
 	public static String PrepareGHNsXML(ResultSet res, ArrayList<String> relatedGHNs){
-		StringBuilder temp = new StringBuilder(),
-			runningInstancesString ;
+		Document doc= null;
+        try {
+        	doc= DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+		} catch (ParserConfigurationException e1) {
+			logger.error("Error creating XML Message");
+			e1.printStackTrace();
+		}
+		Element root= doc.createElement("ResultSet");
+		
 		ResultSet riRes;
-		String selectedString="false";
-		temp.append("<ResultSet>");
+						
 		try{
 			while (res.next()){
-					selectedString= relatedGHNs.contains(res.getString("ID")) ? "true" : "false";
 					riRes= DBInterface.queryDB("select RI.id, RI.name from RUNNINGINSTANCE as RI, GHNRELATEDRI as REL where REL.GHNID='"+res.getString("ID")+"' and REL.RIID=RI.ID");
-					runningInstancesString= new StringBuilder();
+					Element risElement=doc.createElement("RunningInstances");
 					while (riRes.next()){
-						runningInstancesString.append("<RunningInstance id=\"");
-						runningInstancesString.append(riRes.getString(1));
-						runningInstancesString.append("\" name=\"");
-						runningInstancesString.append(riRes.getString(2));
-						runningInstancesString.append("\" />");
+						Element riElement= createTextElement(doc, "RunningInstances", null, new Couple<String, String>("id", riRes.getString(1)), new Couple<String, String>("name", riRes.getString(2)));
+						risElement.appendChild(riElement);
 					}
 					
-					temp.append("<GHN><ID>");
-					temp.append(res.getString(1));
-					temp.append("</ID><Host>");
-					temp.append(res.getString(2));
-					temp.append("</Host><Info><Security>");
-					temp.append(res.getString(3));
-					temp.append("</Security><UpTime>");
-					temp.append(res.getString(4));
-					temp.append("</UpTime><Memory><VirtualAvailable>");
-					temp.append(res.getString(5));
-					temp.append("</VirtualAvailable><VirtualSize>");
-					temp.append(res.getString(6));
-					temp.append("</VirtualSize><LocalAvailableSpace>");
-					temp.append(res.getString(7));
-					temp.append("</LocalAvailableSpace></Memory><Site><Location>");
-					temp.append(res.getString(8));
-					temp.append("</Location><Country>");
-					temp.append(res.getString(9));
-					temp.append("</Country><Domain>");
-					temp.append(res.getString(10));
-					temp.append("</Domain></Site><RunningInstances>");
-					temp.append(runningInstancesString);
-					temp.append("</RunningInstances><Libraries></Libraries></Info><Selected>");
-					temp.append(selectedString);
-					temp.append("</Selected></GHN>");
+					Element ghnEl = addElements(doc, "GHN", new Element[]{
+						createTextElement(doc, "ID",res.getString(1)), 
+						createTextElement(doc, "Host",res.getString(2)),
+						addElements(doc, "Info", new Element[]{
+								createTextElement(doc, "Security", res.getString(3)),
+								createTextElement(doc, "UpTime", res.getString(4)),
+								addElements(doc, "Memory", new Element[]{
+										createTextElement(doc, "VirtualAvailable", res.getString(5)),
+										createTextElement(doc, "VirtualSize", res.getString(6)),
+										createTextElement(doc, "LocalAvailableSpace", res.getString(7))}),
+								addElements(doc, "Site", new Element[]{
+										createTextElement(doc, "Location", res.getString(8)),
+										createTextElement(doc, "Country", res.getString(9)),
+										createTextElement(doc, "Domain", res.getString(10))}),
+								createTextElement(doc, "Libraries", null),
+								createTextElement(doc, "Selected", relatedGHNs.contains(res.getString("ID")) ? "true" : "false")
+						})
+					});
+			
+					root.appendChild(ghnEl);
 			}
 		}catch(SQLException e){
 			logger.error("database error "+e.getMessage());
 		}
 		
-		temp.append("</ResultSet>");
+		doc.appendChild(root);
 		//logger.debug("VDLMODEL: request collection XML: "+temp);
-		return temp.toString();
+		
+		return docToString(doc);
 	}
 	
 	/**
@@ -123,89 +136,92 @@ public class XMLUtil {
 	 */
 	public static String PrepareMCFormatXML(ResultSet resNative, ResultSet resDerivable, ResultSet allMF, Hashtable<String, ArrayList<String>> selectedMetadata){
 		
-		Hashtable<String, ArrayList<String>> MDFHash= new Hashtable<String, ArrayList<String>>();
-		StringBuilder temp;
-		StringBuilder keyTemp=null;
-		StringBuilder totalMFList=new StringBuilder();
-		totalMFList.append("<MFL>");
-		ArrayList<String> tempArray;
-		try{
+		Document doc= null;
+        try {
+        	doc= DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+		} catch (ParserConfigurationException e1) {
+			logger.error("Error creating XML Message");
+			e1.printStackTrace();
+		}
+		Hashtable<Element, ArrayList<Element>> MDFHash= new Hashtable<Element, ArrayList<Element>>();
 			
+		Element mflEl= doc.createElement("MFL");
+		ArrayList<Element> tempArray;
+		try{
 			while (allMF.next())
 			{
-				temp= new StringBuilder();
-				temp.append("<Element><MFID>");
-				temp.append(allMF.getString(1));
-				temp.append("</MFID><MFName>");
-				temp.append(allMF.getString(2));
-				temp.append("</MFName><URI>");
-				temp.append(allMF.getString(3));
-				temp.append("</URI><Language>");
-				temp.append(allMF.getString(4));
-				temp.append("</Language></Element>");
-				totalMFList.append(temp);
+				
+				Element elementEl=addElements(doc, "Element", new Element[]{
+						createTextElement(doc, "MFID", allMF.getString(1)),
+						createTextElement(doc, "MFName", allMF.getString(2)),
+						createTextElement(doc, "URI", allMF.getString(3)),
+						createTextElement(doc, "Language", allMF.getString(4))
+				}); 
+				mflEl.appendChild(elementEl);
 			}
 			
-			totalMFList.append("</MFL>");
-			
+			//setting the native MDF
 			while(resNative.next()){
-				keyTemp= new StringBuilder();
-				keyTemp.append("<CollectionID>");
-				keyTemp.append(resNative.getString(1));
-				keyTemp.append("</CollectionID><Name>");
-				keyTemp.append(resNative.getString(2));
-				keyTemp.append("</Name><Description>");
-				keyTemp.append(resNative.getString(3));
-				keyTemp.append("</Description>");
-				temp= new StringBuilder();
-				temp.append("<MetadataFormat><Id>");
-				temp.append(resNative.getString(4));
-				if(selectedMetadata.isEmpty())
-					temp.append("</Id><Selectable>True</Selectable><Selected>True</Selected></MetadataFormat>");
+				Element tmpKeyEl= addElements(doc, "Collection", new Element[]{
+						createTextElement(doc,"CollectionID" , resNative.getString(1)),
+						createTextElement(doc,"Name" , resNative.getString(2)),
+						createTextElement(doc,"Description" , resNative.getString(3))
+				});
+				
+				Element tmpEl;
+				
+				if(selectedMetadata.isEmpty() || (selectedMetadata.containsKey(resNative.getString(1))) && (selectedMetadata.get(resNative.getString(1)).contains(resNative.getString(4))) )
+					 tmpEl= addElements(doc, "MetadataFormat", new Element[]{
+								createTextElement(doc, "Id", resNative.getString(4)),
+								createTextElement(doc, "Selectable", "True"),
+								createTextElement(doc, "Selected", "True"),
+						});
 				else{
-					if((selectedMetadata.containsKey(resNative.getString(1))) && (selectedMetadata.get(resNative.getString(1)).contains(resNative.getString(4))))
-						temp.append("</Id><Selectable>True</Selectable><Selected>True</Selected></MetadataFormat>");
-					else
-						temp.append("</Id><Selectable>True</Selectable><Selected>False</Selected></MetadataFormat>");
+					tmpEl= addElements(doc, "MetadataFormat", new Element[]{
+							createTextElement(doc, "Id", resNative.getString(4)),
+							createTextElement(doc, "Selectable", "True"),
+							createTextElement(doc, "Selected", "False"),
+					});
 				}
 				//logger.debug("MDFProva: "+keyTemp+" "+temp);
-				
-								
-				if(MDFHash.contains(keyTemp.toString())) MDFHash.get(keyTemp.toString()).add(temp.toString());
+				if(MDFHash.contains(tmpKeyEl)) MDFHash.get(tmpKeyEl).add(tmpEl);
 				else{
-					tempArray=new ArrayList<String>();
-					tempArray.add(temp.toString());
-					MDFHash.put(keyTemp.toString(), tempArray );
+					tempArray=new ArrayList<Element>();
+					tempArray.add(tmpEl);
+					MDFHash.put(tmpKeyEl, tempArray );
 				}
 				//logger.debug("MDFProva: Native "+MDFHash.get(keyTemp).size());
 			}
 			
+			
+			//setting the derivable MDF
 			while(resDerivable.next()){
-				keyTemp= new StringBuilder();
-				keyTemp.append("<CollectionID>");
-				keyTemp.append(resDerivable.getString(1));
-				keyTemp.append("</CollectionID><Name>");
-				keyTemp.append(resDerivable.getString(2));
-				keyTemp.append("</Name><Description>");
-				keyTemp.append(resDerivable.getString(3));
-				keyTemp.append("</Description>");
-				temp= new StringBuilder();
-				temp.append("<MetadataFormat><Id>");
-				temp.append(resDerivable.getString(4));
-				if(selectedMetadata.isEmpty())
-					temp.append("</Id><Selectable>True</Selectable><Selected>False</Selected></MetadataFormat>");
+				Element tmpKeyEl= addElements(doc, "Collection", new Element[]{
+						createTextElement(doc,"CollectionID" , resDerivable.getString(1)),
+						createTextElement(doc,"Name" , resDerivable.getString(2)),
+						createTextElement(doc,"Description" , resDerivable.getString(3))
+				});
+				
+				Element tmpEl;
+				if(selectedMetadata.isEmpty() || !(selectedMetadata.containsKey(resDerivable.getString(1))) && (selectedMetadata.get(resDerivable.getString(1)).contains(resDerivable.getString(4))))
+					tmpEl= addElements(doc, "MetadataFormat", new Element[]{
+							createTextElement(doc, "Id", resDerivable.getString(4)),
+							createTextElement(doc, "Selectable", "True"),
+							createTextElement(doc, "Selected", "False"),
+					});
 				else{
-					if((selectedMetadata.containsKey(resDerivable.getString(1))) && (selectedMetadata.get(resDerivable.getString(1)).contains(resDerivable.getString(4))))
-						temp.append("</Id><Selectable>True</Selectable><Selected>True</Selected></MetadataFormat>");
-					else 
-						temp.append("</Id><Selectable>True</Selectable><Selected>False</Selected></MetadataFormat>");
+					tmpEl= addElements(doc, "MetadataFormat", new Element[]{
+							createTextElement(doc, "Id", resDerivable.getString(4)),
+							createTextElement(doc, "Selectable", "False"),
+							createTextElement(doc, "Selected", "False"),
+					});
 				}
 				//logger.debug("MDFProva: Derivable "+keyTemp+" "+temp);
-				if(MDFHash.contains(keyTemp.toString())) MDFHash.get(keyTemp.toString()).add(temp.toString());
+				if(MDFHash.contains(tmpKeyEl)) MDFHash.get(tmpKeyEl).add(tmpEl);
 				else{
-					tempArray=new ArrayList<String>();
-					tempArray.add(temp.toString());
-					MDFHash.put(keyTemp.toString(), tempArray );
+					tempArray=new ArrayList<Element>();
+					tempArray.add(tmpEl);
+					MDFHash.put(tmpKeyEl, tempArray );
 				}
 			}
 			
@@ -215,44 +231,31 @@ public class XMLUtil {
 			e.printStackTrace();
 		}
 		
-		StringBuilder resultString= new StringBuilder();
-		
-		resultString.append("<ResultSet>");
-		resultString.append(totalMFList);
-		resultString.append("<CollectionList>");
-		String key;
-		Enumeration<String> k=MDFHash.keys();
+		Element collectionListEl= doc.createElement("CollectionList");
+		Element key;
+		Enumeration<Element> k=MDFHash.keys();
 		while (k.hasMoreElements()){
 			key= k.nextElement();
-			ArrayList<String> tempMD=MDFHash.get(key);
+			ArrayList<Element> tempMD=MDFHash.get(key);
 			//logger.debug("ArrayProva"+tempMD.size());
-			resultString.append("<Collection>");
-			resultString.append(key);
-			resultString.append("<MetadataFormatList>");;
-			for (String obj: tempMD){
-				resultString.append(obj);
-				//logger.debug("ArrayProva "+obj);
-			}
-			resultString.append("</MetadataFormatList></Collection>");
-			
+			collectionListEl.appendChild(addElements(doc, "Collection", new Element[]{
+					key, addElements(doc, "MetadataFormatList", tempMD.toArray(new Element[0]))
+			}));
 		}
 		
-		resultString.append("</CollectionList></ResultSet>");
+		doc.appendChild(addElements(doc, "ResultSet", new Element[]{mflEl, 	collectionListEl}));
 		//logger.debug("VDLMODEL: request MCFormat XML "+resultString);
-		return resultString.toString();
+		return docToString(doc);
 	}
 	
 	/**
-	 * 
-	 * @param resNative
-	 * @param resDerivable
-	 * @return
+	 * 	
+	 * @return the XML representing the quality string
 	 */
 	public static String PrepareQualityXML(){
 		StringBuilder qualityString=new StringBuilder();
 		qualityString.append("<ResultSet>");
 		qualityString.append("<Quality><DisplayName>Response Time</DisplayName><Description>This quality parameter indicates the importance of response time (i.e., the delay from a function request to the reception of the response) ");
-		
 		qualityString.append("in selecting the resource (both in number and type) needed to satisfy the Digital Library definition criteria. E.g., the specification of a 100% response time will result in a maximization of the resources ");
 		qualityString.append("allocated as to minimise the response time. </Description><Multiple value=\"true\"/><CanBeEmpty value=\"false\"/><AllowedValues><Value default=\"true\" selected=\"false\">*</Value></AllowedValues></Quality>");
 		qualityString.append("<Quality><DisplayName>Robustness</DisplayName><Description>This quality parameter indicates the importance of robustness (i.e., the resilience to faults) in selecting the resource (both in number and type)");
@@ -275,43 +278,44 @@ public class XMLUtil {
 	
 	/**
 	 * 
+	 * @param res
+	 * @param selectedFunct
+	 * @param selectedCS
+	 * @return
 	 */
+	@SuppressWarnings("unchecked")
 	public static String PrepareFunctionalityXML(ResultSet res, ArrayList<Integer> selectedFunct, ArrayList<String> selectedCS){
-		StringBuilder toReturn=new StringBuilder();
-		toReturn.append("<Resultset>");
+		
+		Document doc= null;
+        try {
+        	doc= DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
+		} catch (ParserConfigurationException e1) {
+			logger.error("Error creating XML Message");
+			e1.printStackTrace();
+		}
+		Element root= doc.createElement("ResultSet");
+		
 		try {
 			while(res.next()){
-				StringBuilder temp= new StringBuilder();
-				temp.append("<Functionality id=\"");
-				temp.append(res.getInt(1));
-				temp.append("\" name=\"");
-				temp.append(res.getString(2));
-				temp.append("\" ");
-				if (res.getInt(1)==10) temp.append(" enableCS=\"true\" ");
-				if(selectedFunct.contains(res.getInt(1))) temp.append("selected=\"true\">");
-				else {
-					temp.append("selected=\"false\">");
-					temp.append("<FunctionalityDescription>");
-					temp.append(res.getString(3));
-					temp.append("</FunctionalityDescription>");
-				}
+								
+				Element functionalityEl= createTextElement(doc, "Functionality", null, new Couple<String, String>("id", res.getInt(1)+""), 
+							new Couple<String, String>("name", res.getString(2)),
+							new Couple<String, String>("enableCS", res.getInt(1)==10 ? "true" : "false"),
+							new Couple<String, String>("selected", selectedFunct.contains(res.getInt(1)) ? "true" : "false")
+					);
+				functionalityEl.appendChild(createTextElement(doc, "FunctionalityDescription", res.getString(3)));
+				
 				ResultSet subFunctRes=DBInterface.queryDB("select * from FUNCTIONALITY where father='"+res.getInt(1)+"';");
 				while(subFunctRes.next()){
-					temp.append("<child>");
-					temp.append("<Functionality id=\"");
-					temp.append(subFunctRes.getInt(1));
-					temp.append("\" name=\"");
-					temp.append(subFunctRes.getString(2));
-					temp.append("\" ");
-                    if(selectedFunct.contains(subFunctRes.getInt(1))) temp.append("selected=\"true\">");
-                    else temp.append("selected=\"false\">");
-                    temp.append("<FunctionalityDescription>");
-                    temp.append(subFunctRes.getString(3));
-                    temp.append("</FunctionalityDescription>");
-                    temp.append("</Functionality></child>");
+					Element subFunctEl=createTextElement(doc,"Functionality" , null, new Couple<String, String>("id", subFunctRes.getInt(1)+""), 
+								new Couple<String, String>("name", subFunctRes.getString(2)),
+								new Couple<String, String>("enableCS", subFunctRes.getInt(1)==10 ? "true" : "false"),
+								new Couple<String, String>("selected", selectedFunct.contains(subFunctRes.getInt(1)) ? "true" : "false"));
+					
+					subFunctEl.appendChild(createTextElement(doc, "FunctionalityDescription", subFunctRes.getString(3)));
+					functionalityEl.appendChild(addElements(doc, "child", new Element[]{subFunctEl}));				
 				}
-				temp.append("</Functionality>");
- 			    toReturn.append(temp);
+				root.appendChild(functionalityEl);
 			}
 		} catch (SQLException e) {
 			logger.error("VDLModelService: DB error preparing XML for Functionality");
@@ -321,31 +325,15 @@ public class XMLUtil {
 		try {
 			ResultSet csRes=DBInterface.queryDB("select * from cs;");
 			if (csRes.next()){
-							
-				StringBuilder temp= new StringBuilder();
-				temp.append("<CS id=\"-1\" name=\"Workflows\" ");
-				//if(selectedFunct.contains(res.getInt(1))) temp+="selected=\"true\">";
-				//else 
-				temp.append("selected=\"false\">");
-				temp.append("<CSDescription>This class of functions contains compound functions defined by aggregating existing functions in structured workflows as to deliver advanced features.</CSDescription>");				
-				
+				Element csEl= createTextElement(doc, "CS", null, new Couple<String, String>("id", "-1"), new Couple<String, String>("name", "Workflows"), new Couple<String, String>("selected", "false"));
+				csEl.appendChild(createTextElement(doc,"CSDescription" , "This class of functions contains compound functions defined by aggregating existing functions in structured workflows as to deliver advanced features."));
 				do{
-					temp.append("<child><CS id=\"");
-					temp.append(csRes.getString(1));
-					temp.append("\" name=\"");
-					temp.append(csRes.getString(2));
-					temp.append("\" ");
-					if(selectedCS.contains(csRes.getString(1))) temp.append("selected=\"true\">");
-					else temp.append("selected=\"false\">");
-					temp.append("<CSDescription>");
-					temp.append(csRes.getString(3));
-					temp.append("</CSDescription>");
-					temp.append("</CS></child>");
-				
+					Element subCsEl= createTextElement(doc, "CS", null, new Couple<String, String>("id", csRes.getString(1)), new Couple<String, String>("name", csRes.getString(2)), new Couple<String, String>("selected", selectedCS.contains(csRes.getString(1)) ? "true" : "false"));
+					subCsEl.appendChild(createTextElement(doc,"CSDescription" , csRes.getString(3)));
+					csEl.appendChild(addElements(doc, "child", new Element[]{subCsEl}));
 				}while (csRes.next());
-				temp.append("</CS>");
-				toReturn.append(temp);
-
+			
+				root.appendChild(csEl);
 			}
 			
 			
@@ -353,9 +341,8 @@ public class XMLUtil {
 			logger.error("VDLModelService: DB error retreiving CS");
 			e.printStackTrace();
 		}
-		
-		toReturn.append("</Resultset>");
-		return toReturn.toString();
+		doc.appendChild(root);
+		return docToString(doc);
 	}
 	
 	
@@ -408,5 +395,61 @@ public class XMLUtil {
 		return toReturn.toString();
 	}	
 
+	/**
+	 * transform a Document into string
+	 * 
+	 * @param doc Document
+	 * @return a String
+	 */
+	public static String docToString(Document doc){
+		
+		String temp= null;
+		try{
+			DOMSource domSource = new DOMSource(doc);
+			
+			TransformerFactory tf = TransformerFactory.newInstance();
+			Transformer serializer = tf.newTransformer();
+			StringWriter sw= new StringWriter();
+			StreamResult sr= new StreamResult(sw);
+			serializer.transform(domSource, sr);
+			temp=sr.getWriter().toString();
+		}catch(Exception e){
+			logger.error("transformation to String Error");
+			e.printStackTrace();
+		}
+		return temp;
+	}
+	/**
+	 * 
+	 * @param doc the root Document
+	 * @param root the element tag name
+	 * @param elements elements to add
+	 * @return the result element
+	 */
+	public static Element addElements(Document doc, String root, Element[] elements){
+		Element returnEl= doc.createElement(root);
+		for (Element el: elements){
+			returnEl.appendChild(el);
+		}
+		return returnEl;
+	}
+	
+	/**
+	 * 
+	 * @param doc the root Document
+	 * @param Tag the element tag name
+	 * @param text the text to add at the element
+	 * @return the result element
+	 */
+	public static Element createTextElement(Document doc, String Tag, String text, Couple<String, String> ... attributes ){
+		Element returnEl= doc.createElement("UpTime");
+		if (attributes!=null){
+			for (Couple<String, String> attribute : attributes){
+				returnEl.setAttribute(attribute.first, attribute.second);
+			}
+		}
+		if (text!=null) returnEl.appendChild(doc.createTextNode(text));
+		return returnEl;
+	}
 	
 }