A little help with XML

Question

Nperic 0 Newbie Poster

15 Years Ago

Hey there,
I am just a little confused with the code below, i parse the XML file although i cant call functions from outside the main. My programming isnt really up to scratch. Ive had a long break so now im paying for it :(

Any help/ suggestions would be very grateful!

package Util;
ALL IMPORTS DONE BY ECLIPSE

public class XMLreader{	

	public static void main(String argv[]){
		try{	
			File file = new File("c:\\Programming Garmin Files\\2009-01-26-09-00-09.tcx");
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			Document doc = db.parse(file);
			doc.getDocumentElement().normalize();
			System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
			NodeList nodeLst = doc.getElementsByTagName("Trackpoint");
			
			//this works but i wish to call the functions from outside this class
			readLatitude(nodeLst, 5);
		}catch(Exception e){
			e.printStackTrace();
		}
	}

	public static float readLatitude(NodeList nodeLst, int index){
		float latArr[] = new float[nodeLst.getLength()];
		try{
			for(int i=0; i<nodeLst.getLength(); i++){
				Node fstNode = nodeLst.item(i);
				if(fstNode.getNodeType() == Node.ELEMENT_NODE){
					Element fstElmnt =(Element)fstNode;
					
					NodeList latiElmntLst = fstElmnt.getElementsByTagName("LatitudeDegrees");
				    Element latiElmnt = (Element) latiElmntLst.item(0);
			    	NodeList latitude = latiElmnt.getChildNodes();
			    	latArr[i] = Float.valueOf(latitude.item(0).getNodeValue().trim()).floatValue();
			    	System.out.println("Latitude Degrees :"+ latArr[i]);
				}
			}
		}catch(NullPointerException e){
			e.printStackTrace();
		}
		//System.out.println(latArr[index]);
		return latArr[index];
	}
	public static float readLongitude(NodeList nodeLst, int index){
		float longArr[] = new float[nodeLst.getLength()];
		for(int i=0; i<nodeLst.getLength(); i++){
			Node fstNode = nodeLst.item(i);
			if(fstNode.getNodeType() == Node.ELEMENT_NODE){
				Element fstElmnt =(Element)fstNode;
				
				NodeList longElmntLst = fstElmnt.getElementsByTagName("LongitudeDegrees");
		    	Element longElmnt = (Element) longElmntLst.item(0);
		    	NodeList longitude = longElmnt.getChildNodes();
		    	longArr[i] = Float.valueOf(longitude.item(0).getNodeValue().trim()).floatValue();
		    	//System.out.println("Longitude Degrees :"+ longArr[i]);
			}
		}
		return longArr[index];
	}
	
	public static float readAltitude(NodeList nodeLst, int index){
		float altArr[] = new float[nodeLst.getLength()];
		try{
			for(int i=0; i<nodeLst.getLength(); i++){
				Node fstNode = nodeLst.item(i);
				if(fstNode.getNodeType() == Node.ELEMENT_NODE){
					Element fstElmnt =(Element)fstNode;
					
					NodeList altElmntLst = fstElmnt.getElementsByTagName("LongitudeDegrees");
			    	Element altElmnt = (Element) altElmntLst.item(0);
			    	NodeList altitude = altElmnt.getChildNodes();
			    	altArr[i] = Float.valueOf(altitude.item(0).getNodeValue().trim()).floatValue();
			    	//System.out.println("Altitude Degrees :"+ altArr[i]);
				}
			}
		}catch(NullPointerException e){
			e.printStackTrace();
		}
		return altArr[index];
	}

	public static void readDate(NodeList nodeLst){
		for(int i= 0; i<nodeLst.getLength(); i++){
			Node fstNode = nodeLst.item(i);			
			if(fstNode.getNodeType() == Node.ELEMENT_NODE){
				Element fstElmnt =(Element)fstNode;
				
				NodeList dateElmntLst = fstElmnt.getElementsByTagName("Time");
		    	Element dateElmnt = (Element) dateElmntLst.item(0);
		    	NodeList date = dateElmnt.getChildNodes();
		    	
		    	//System.out.println("Time :"+((Node)date.item(0)).getNodeValue().trim());
		    	String dateStr = ((Node)date.item(0)).getNodeValue().trim().toString();
		    	String temp[]; temp = dateStr.split("T");
		   		System.out.println("Date: " + temp[0] + "    Time: " + temp[1]);
			}
		}
	}
	
	public static void readDistance(NodeList nodeLst){
		for(int i= 0; i<nodeLst.getLength(); i++){
			Node fstNode = nodeLst.item(i);			
			if(fstNode.getNodeType() == Node.ELEMENT_NODE){
				Element fstElmnt =(Element)fstNode;
				
				NodeList distElmntLst = fstElmnt.getElementsByTagName("DistanceMeters");
		    	Element distElmnt = (Element) distElmntLst.item(0);
		    	NodeList distance = distElmnt.getChildNodes();
		    	float fDistance = Float.valueOf(distance.item(0).getNodeValue().trim()).floatValue();
		    	System.out.println("Distance(meters) :"+ fDistance);
			}
		}
	}
	
	public float getLongitude(int index){
		return readLongitude(nodeLst, index);
	}
	public float getLatitude(int index){
		return readLatitude(nodeLst, index);
	}
	public float getAltitude(int index){
		return readAltitude(nodeLst, index);
	}
	
	
	
}

thanks again!

java

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6 Replies
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Latest Post 15 Years Ago Latest Post by Ezzaral

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JamesCherrill 4,733 Most Valuable Poster

15 Years Ago

You call a public static method from outside the class by using itsclass name and method name, eg
XMLreader.readLatitude(...)

JamesCherrill 4,733 Most Valuable Poster

15 Years Ago

OK, misunderstood Q. Sorry.
Can't see why you're passing nodeLst around like that. It's set up during initialisation, and then accessed by all the methods, so why not make it a variable at the class level and let all the methods access it directly? In that case all you need to pass in the index you want.
ps: You may be getting into problems mixing static and non-static in this code. It looks like you are getting the XML data from a file, then providing access to results calculated from it. Maybe you should make all the code non-static, and just instantiate an instance for each data file - move your code from main(...) to a new constructor that takes the file as a parameter: public XMLreader(File file) { etc } then create it from the main method:

public static void main(String argv[]){
  XMLReader reader =   new XMLreader(new File("...");
  reader.readAltitude(index)...
}

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Nperic 0 Newbie Poster · Answer 1 · 2009-04-15T19:41:20+00:00

You call a public static method from outside the class by using itsclass name and method name, eg
XMLreader.readLatitude(...)

Oh, what i meant was the functions down below aren't recognizing the nodelist made in the main. So it requires a null variable to be initialized.

public float getDistance(int index){
		return XMLreader.readAltitude(nodeLst, index);
	}

brings up this error.

- nodeLst cannot be resolved

Thankyou for your response :D

Nperic 0 Newbie Poster · Answer 2 · 2009-04-16T11:29:55+00:00

Thanks James!
You have totally changed my perspective on how i designed the class! Very thankful for that. Now i am stuck with another error :(

When i run the function in the main, the functions list the values although theyre stopped by a NullPointerException.

double altitude = Double.parseDouble(altList.item(0).getTextContent());

seems to be the problem, i think it is the way i am gathering the values or the way i am converting the values.
Here is the new revamped code :D

package gps;

import java.io.File;
import java.io.IOException;
import java.util.GregorianCalendar;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import model.Activity;
import model.Author;
import model.Creator;
import model.Lap;
import model.Position;
import model.TrackPoint;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class XMLReader{
	public static void main(String[] args) throws Exception{
		String inFile = "c:\\Programming Garmin Files\\2009-01-26-09-00-09.tcx";
XMLReader reader = new XMLReader();



//reader.posReader(inFile);
	reader.trackReader(inFile);
	
	reader.lapReader(inFile);
	reader.creatorReader(inFile);
	reader.authorReader(inFile);
	reader.activityReader(inFile);
}


public Position[] posReader(String inFile) throws Exception{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Trackpoint");

Position[] position = new Position[nodeLst.getLength()];
for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		NodeList latList = fstElmnt.getElementsByTagName("LatitudeDegrees");
double latitude = Double.parseDouble(latList.item(0).getTextContent());
NodeList longList = fstElmnt.getElementsByTagName("LongitudeDegrees");
double longitude = Double.parseDouble(longList.item(0).getTextContent());

//TEST
/*
System.out.println("BLOCK---------------------");
System.out.println("Latitude: " + latitude);
System.out.println("Longitude: " + longitude);
*/
			position[i] = new Position(latitude, longitude);
		}
	}
	return position;		
}
public TrackPoint[] trackReader(String inFile) throws ParserConfigurationException, SAXException, IOException{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Trackpoint");

TrackPoint[] trackpoint = new TrackPoint[nodeLst.getLength()];
for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		//String time = fstNode.getFirstChild().getTextContent();
GregorianCalendar timeDate = new GregorianCalendar();
NodeList altList = fstElmnt.getElementsByTagName("AltitudeMeters"); 
double altitude = Double.parseDouble(altList.item(0).getTextContent());
NodeList distList = fstElmnt.getElementsByTagName("DistanceMeters");
double distance = Double.parseDouble(distList.item(0).getTextContent());

//TEST
/*
System.out.println("BLOCK---------------------");
System.out.println("Altitude: " + altitude);
System.out.println("Distance: " + distance);
*/
			
			trackpoint[i] = new TrackPoint(timeDate, null, altitude, distance);
		}
	}
	return trackpoint;		
}
public Lap[] lapReader(String inFile) throws ParserConfigurationException, SAXException, IOException{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Activity");

Lap[] lap = new Lap[nodeLst.getLength()];
for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		//String time = fstNode.getFirstChild().getTextContent();
GregorianCalendar timeDate = new GregorianCalendar();
NodeList ttsList = fstElmnt.getElementsByTagName("TotalTimeSeconds"); 
double totaltime = Double.parseDouble(ttsList.item(0).getTextContent());
NodeList distList = fstElmnt.getElementsByTagName("DistanceMeters");
double distance = Double.parseDouble(distList.item(0).getTextContent());
NodeList maxList = fstElmnt.getElementsByTagName("MaximumSpeed");
double maxSpeed = Double.parseDouble(maxList.item(0).getTextContent());
NodeList calList = fstElmnt.getElementsByTagName("Calories");
double calories = Double.parseDouble(calList.item(0).getTextContent());
NodeList intList = fstElmnt.getElementsByTagName("Intensity");
String intensity = intList.item(0).getTextContent();
NodeList cadList = fstElmnt.getElementsByTagName("Cadence");
int cadence = Integer.parseInt(cadList.item(0).getTextContent());
NodeList trigList = fstElmnt.getElementsByTagName("TriggerMethod");
String triggerMethod = trigList.item(0).getTextContent();

//TEST
/*
System.out.println("BLOCK---------------------");
System.out.println("TotalTime: " + totaltime);
System.out.println("Distance: " + distance);
System.out.println("Max Speed: " + maxSpeed);
System.out.println("Calories: " + calories);
System.out.println("Intensity: " + intensity);
System.out.println("Cadence: " + cadence);
System.out.println("Trigger Method: " + triggerMethod);
*/
			lap[i] = new Lap(timeDate, totaltime, distance, maxSpeed, calories, intensity, cadence, triggerMethod);
		}
	}
	return lap;
}
public Creator[] creatorReader(String inFile) throws ParserConfigurationException, SAXException, IOException{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Activity");

Creator[] creator = new Creator[nodeLst.getLength()];
for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		//String time = fstNode.getFirstChild().getTextContent();
NodeList nameList = fstElmnt.getElementsByTagName("Name"); 
String name = nameList.item(0).getTextContent();
NodeList unitList = fstElmnt.getElementsByTagName("UnitId");
String unitId = unitList.item(0).getTextContent();
NodeList prodList = fstElmnt.getElementsByTagName("ProductID");
int prodId = Integer.parseInt(prodList.item(0).getTextContent());
NodeList versList = fstElmnt.getElementsByTagName("VersionMajor");
String version = versList.item(0).getTextContent();

//TEST
/*
System.out.println("BLOCK---------------------");
System.out.println("Product Name: " + name);
System.out.println("UnitID: " + unitId);
System.out.println("ProductID: " + prodId);
System.out.println("Version(major): " + version);
*/
			
			creator[i] = new Creator(name, unitId, prodId, version);
		}
	}
	return creator;
}

public Author[] authorReader(String inFile) throws ParserConfigurationException, SAXException, IOException{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Author");

Author[] author = new Author[nodeLst.getLength()];
for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		NodeList nameList = fstElmnt.getElementsByTagName("Name"); 
String name = nameList.item(0).getTextContent();
NodeList bversList = fstElmnt.getElementsByTagName("VersionMajor"); 
String bvers = bversList.item(0).getTextContent();
NodeList typeList = fstElmnt.getElementsByTagName("Type"); 
String type = typeList.item(0).getTextContent();
NodeList langList = fstElmnt.getElementsByTagName("LangID"); 
String langID = langList.item(0).getTextContent();
NodeList partList = fstElmnt.getElementsByTagName("PartNumber"); 
String partNum = partList.item(0).getTextContent();

//TEST
/*
System.out.println("BLOCK---------------------");
System.out.println("Name: " + name);
System.out.println("Version: " + bvers);
System.out.println("Type: " + type);
System.out.println("LangID: " + langID);
System.out.println("Part Number: " + partNum);
*/
			
			author[i] = new Author(name, bvers, type, langID, partNum);
		}
	}
	return author;
}
public Activity[] activityReader(String inFile) throws ParserConfigurationException, SAXException, IOException{
	File file = new File(inFile);
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(file);
	doc.getDocumentElement().normalize();
	System.out.println("Root element: " + doc.getDocumentElement().getNodeName() + "\n");
NodeList nodeLst = doc.getElementsByTagName("Activities");
NodeList nodeLst2 = doc.getElementsByTagName("Creator");
Activity[] activity = new Activity[nodeLst.getLength()];
List<Lap> laps = null;

for(int i= 0; i<nodeLst.getLength(); i++){
	Node fstNode = nodeLst.item(i);			
	if(fstNode.getNodeType() == Node.ELEMENT_NODE){
		Element fstElmnt =(Element)fstNode;
		String sport = fstNode.getFirstChild().getNodeName();
		NodeList idList = fstElmnt.getElementsByTagName("Id"); 
String Id = idList.item(0).getTextContent();

//creator
for(int j=0; j<nodeLst.getLength(); j++){
	Node scndNode = nodeLst2.item(i);			
	if(scndNode.getNodeType() == Node.ELEMENT_NODE){
		NodeList nameList = fstElmnt.getElementsByTagName("Name"); 
	String name = nameList.item(0).getTextContent();
	NodeList unitList = fstElmnt.getElementsByTagName("UnitId");
	String unitId = unitList.item(0).getTextContent();
	NodeList prodList = fstElmnt.getElementsByTagName("ProductID");
	int prodId = Integer.parseInt(prodList.item(0).getTextContent());
	NodeList versList = fstElmnt.getElementsByTagName("VersionMajor");
	String version = versList.item(0).getTextContent();
	
	activity[i] = new Activity(sport, Id, laps, new Creator(name, unitId, prodId, version));
	
	//TEST
	/*
	System.out.println("BLOCK---------------------");
	System.out.println("Sport: " + sport);
	System.out.println("ID: " + Id);
	System.out.println("Name: " + name);
	System.out.println("UnitID: " + unitId);
	System.out.println("ProductID: " + prodId);
	System.out.println("Version(major): " + version);
	*/
					}
				}
				
			}
		}
		return activity;
	}
}

Also, if the XML tags are

<Activities>
		<Activity Sport="Biking">

How do i get the Sport value? i tried getAttributes although it doesnt work :(

Nperic 0 Newbie Poster · Answer 3 · 2009-04-16T12:02:03+00:00

Nperic 0 Newbie Poster

15 Years Ago

And if it helps, here is the XML file. Thank you everyone for your consideration :D

This attachment is potentially unsafe to open. It may be an executable that is capable of making changes to your file system, or it may require specific software to open. Use caution and only open this attachment if you are comfortable working with zip files.

2009-01-26-09-00-09.zip (17.15 KB)

Ezzaral 2,714 Posting Sage Team Colleague Featured Poster · Answer 4 · 2009-04-16T23:46:56+00:00

I believe you should be able to cast the Node to an Element and use Element.getAttribute(java.lang.String)
(Just guessing though - we use JDOM here instead of that api)

A little help with XML

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