Dear All,
I have problems with variables when accessing an XML file. I definitley can set the variables (which I have tested by printing them on the screen) But when I try to use them, e. g. in other methods, they are still 0 or null. Following the two classes and the XML file.
What am I doing wrong?
public class Speed {
private int entryTime;
private int exitTime;
private int length;
private int speedLimit;
private int speed;
private String regno;
public void setEntry(String entry) {
entryTime = Integer.parseInt(entry);
}
public void setExit(String exit) {
exitTime = Integer.parseInt(exit);
//Just to test the variable value
System.out.println(exitTime);
}
public void setLength(String l) {
length = Integer.parseInt(l);
}
public void setSpeedLimit(String sl) {
speedLimit = Integer.parseInt(sl);
}
public void setRegno(String reg) {
regno = reg;
//Just to test the variable value
System.out.println(regno);
}
public int getSpeedLimit() {
return speedLimit;
}
public int getLength() {
return length;
}
void createReport() {
//calculate speed of car
speed = 3600 / 20; //Instead of the 20 there should be (exitTime - entryTime)
//but this always results into / 0. So, for testing, I
//replaced it with 20.
//if speed over limit print car details
if (speed > speedLimit) {
System.out.println("Reg no " + regno + " speed " + speed);
}
}
}
import org.xml.sax.*;
import java.io.*;
import java.util.*;
public class TrafficProcess extends HandlerBase{
//Place your variables here
String elementName;
public TrafficProcess() {
}
public static void main(String[] args) {
try {
System.out.println("...Starting");
Class loadedClass = Class.forName("com.ibm.xml.parser.SAXDriver");
Parser xParser = (Parser)loadedClass.newInstance();
TrafficProcess fp = new TrafficProcess();
xParser.setDocumentHandler(fp);
xParser.setErrorHandler(fp);
xParser.parse("traffic.txt"); //File holding XML DTD and source
}
catch(Exception e)
{System.out.println("Problem with XML processor "+e);}
}
public void error(SAXParseException se){
//No code needed here
}
public void warning(SAXParseException se){
//No code needed here
}
public void startDocument() throws SAXException{
}
public void startElement(String elementName, AttributeList al) throws SAXException{
this.elementName = elementName;
}
public void endElement(String elementName) throws SAXException{
//When the end of element EXITTIME is reached all variables needed to
//calculate the speed and create the report have been set.
//So we can call the appropriate methods now
if (elementName.equals("EXITTIME")) {
Speed s = new Speed();
s.createReport();
}
}
public void endDocument() throws SAXException{
Speed s = new Speed();
System.out.println("Data for M1 Roadworks north of Luton, speed limit "
+ s.getSpeedLimit() + ", length in miles is " + s.getLength());
}
public void characters(char[] chars, int start, int length)throws SAXException{
//Create a String variable stringValue and hand over the value of the
//current element. Then set each variable needed for speed calculation and
//comparison with the value of the corresponding element
String stringValue = new String(chars, start, length);
Speed s = new Speed();
if (elementName.equals("LENGTH"))
s.setLength(stringValue);
if (elementName.equals("SPEEDLIMIT"))
s.setSpeedLimit(stringValue);
if (elementName.equals("ENTRYTIME"))
s.setEntry(stringValue);
if (elementName.equals("EXITTIME"))
s.setExit(stringValue);
if (elementName.equals("REGNO"))
s.setRegno(stringValue);
}
}
<?xml version = "1.0" standalone = "yes"?>
<!DOCTYPE CARLIST[
><!ELEMENT LOCATION (#PCDATA)>
<!ELEMENT LENGTH (#PCDATA)>
<!ELEMENT SPEEDLIMIT (#PCDATA)>
<!ELEMENT CARS (REGNO, ENTRYTIME, EXITTIME)*>
<!ELEMENT REGNO (#PCDATA)>
<!ELEMENT ENTRYTIME (#PCDATA)>
<!ELEMENT EXITTIME (#PCDATA)>
]>
<CARLIST>
<LOCATION> M1 Roadworks north of Luton </LOCATION>
<LENGTH>1</LENGTH>
<SPEEDLIMIT>30</SPEEDLIMIT>
<CARS>
<REGNO>X239FRP</REGNO>
<ENTRYTIME>41000</ENTRYTIME>
<EXITTIME>41060</EXITTIME>
<REGNO>Z239ASW</REGNO>
<ENTRYTIME>41050</ENTRYTIME>
<EXITTIME>41280</EXITTIME>
<REGNO>P389WDE</REGNO>
<ENTRYTIME>42000</ENTRYTIME>
<EXITTIME>42307</EXITTIME>
<REGNO>FE239XTY</REGNO>
<ENTRYTIME>47000</ENTRYTIME>
<EXITTIME>47050</EXITTIME>
</CARS>
</CARLIST>
