Thread: XML with SAX

Greetings all! I have a brief question about parsing an XML document using SAX and DOM. I have an XML document with a structure like this...

<Holidays>
   <Carrier>
      <name>Company 1</name> 
      <interval>5</interval> 
   </Carrier>
   <Carrier>
      <name>company 2</name> 
      <interval>7</interval> 
      <Holiday>
         <Name>Thanksgiving 2009</Name> 
         <Date>11/26/2009</Date> 
      </Holiday>
      <Holiday>
         <Name>Christmas 2009</Name> 
         <Date>12/25/2009</Date> 
      </Holiday>
   </Carrier>
</Holidays>

Not all <Carrier> observe a <Holiday>.. What I am trying to do is get all the <Holiday>s for the <Carrier> that I specify. Do I need to reconstruct my XML or can it be done with the format it is in now?

When I try to get <Date> I end up getting all dates in the entire file, not just the ones that match my specified <Carrier>.

I wrote this little snippet for you.

import java.io.File;
import java.io.IOException;
import java.util.List;
 
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;
 
public class SaxParsing {
 
    @SuppressWarnings("unchecked")
    public static void main(final String... arguments) throws JDOMException, IOException {
        final SAXBuilder builder = new SAXBuilder();
        final Document document = builder.build(new File("c:/holidays.xml"));
 
        System.out.println("-----------------------------------------------------------------------");
        System.out.println("Printing the XML document");
        System.out.println("-----------------------------------------------------------------------");
        System.out.println(new XMLOutputter(Format.getPrettyFormat()).outputString(document));
        System.out.println("");
        System.out.println("-----------------------------------------------------------------------");
 
        final Element rootElement = document.getRootElement();
 
        if (rootElement != null) {
            final List<Element> carrierElements = rootElement.getChildren("Carrier");
 
            if (carrierElements != null && !carrierElements.isEmpty()) {
                for (final Element carrierElement : carrierElements) {
                    if (carrierElement != null) {
                        final List<Element> holidayElements = carrierElement.getChildren("Holiday");
 
                        if (holidayElements != null && !holidayElements.isEmpty()) {
                            for (final Element holidayElement : holidayElements) {
                                if (holidayElement != null) {
                                    System.out.println("");
                                    System.out.println("Found Holiday with " + carrierElement.getChildText("name"));
                                    System.out.println("Name: " + holidayElement.getChildText("Name"));
                                    System.out.println("Date: " + holidayElement.getChildText("Date"));
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

Hope that helps

// Json

JSon,

Thanks for the reply. I had a litle trouble getting it to work but looks like this is going to work much better that the mess I was trying to create. Thanks again.

Now that I have this part working I've been thinking about how to setup the objects. I'm hoping that there is a better way. Currently I have an object Carriers and an object Carrier.

Carriers is setup like this...

package org.me.orderentry;
 
import java.applet.Applet;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
 
public class Carriers {
    private ArrayList<Carrier> carriers = new ArrayList<Carrier>();
    private Applet applet;
    private String carrierList;
 
    public Carriers(Applet a) {
        applet = a;
        carrierList = "";
        setCarriers();
    }
 
    public ArrayList<Carrier> getCarriers() {
        return carriers;
    }
 
    public Carrier getCarrier(int index) {
        return carriers.get(index);
    }
 
    @SuppressWarnings("unchecked")
    public void setCarriers() {
        URL url;
        try {
            url = new URL(applet.getCodeBase(), "/orderentrytoolkit/carriers_xml");
 
            final SAXBuilder builder = new SAXBuilder();
            final Document document = builder.build(url.openStream());
 
            final Element rootElement = document.getRootElement();
 
            if (rootElement != null) {
                final List<Element> carrierElements = rootElement.getChildren("Carrier");
 
                if (carrierElements != null && !carrierElements.isEmpty()) {
                    for (final Element carrierElement : carrierElements) {
                        if (carrierElement != null) {
                            carriers.add(new Carrier(applet, carrierElement.getChildText("Name")));
                        }
                    }
                }
            }
        } catch (IOException err) {
            err.printStackTrace();
        } catch (JDOMException err) {
            err.printStackTrace();
        }
    }
}

and carrier is setup like this...

package org.me.orderentry;
 
import java.applet.Applet;
import java.io.IOException;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
 
import java.util.Date;
import java.util.List;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
 
public class Carrier {
 
    Applet applet;
    private String name;
    private int interval;
    private ArrayList<String> holidays = new ArrayList<String>();
    SimpleDateFormat formatter;
 
    public Carrier(Applet a, String newName) {
        applet = a;
        name = newName;
        interval = 0;
        formatter = new SimpleDateFormat("MM/dd/yyyy");
        setCarrier();
    }
 
    public void setName(String newValue) {
        name = newValue;
    }
 
    public String getName() {
        return name;
    }
 
    public void setInterval(int newValue) {
        interval = newValue;
    }
 
    public int getInterval() {
        return interval;
    }
 
    public boolean isHoliday(Date date) {
        String tmpDate = formatter.format(date);
        if (holidays.contains(tmpDate)) {
            return true;
        } else {
            return false;
        }
    }
 
    public ArrayList<String> getHolidays() {
        return holidays;
    }
 
    @SuppressWarnings("unchecked")
    public void setCarrier() {
        URL url;
        try {
            url = new URL(applet.getCodeBase(), "/orderentrytoolkit/carriers_xml");
 
            final SAXBuilder builder = new SAXBuilder();
            final Document document = builder.build(url.openStream());
 
            final Element rootElement = document.getRootElement();
 
            if (rootElement != null) {
                final List<Element> carrierElements = rootElement.getChildren("Carrier");
 
                if (carrierElements != null && !carrierElements.isEmpty()) {
                    for (final Element carrierElement : carrierElements) {
                        if (carrierElement != null) {
                            if (name.equals(carrierElement.getChildText("Name"))) {
                                interval = Integer.parseInt(carrierElement.getChildText("Interval"));
 
                                final List<Element> holidaysElements = carrierElement.getChildren("Holidays");
                                if (holidaysElements != null && !holidaysElements.isEmpty()) {
                                    for (final Element holidaysElement : holidaysElements) {
                                        final List<Element> holidayElements = holidaysElement.getChildren("Holiday");
 
 
                                        if (holidayElements != null && !holidayElements.isEmpty()) {
                                            for (final Element holidayElement : holidayElements) {
                                                if (holidayElement != null) {
                                                    holidays.add(holidayElement.getChildText("Date"));
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        } catch (IOException err) {
            err.printStackTrace();
        } catch (JDOMException err) {
            err.printStackTrace();
        }
    }
}

I suppose my question is if ArrayList is ok to use in this case or if I should try a different approach. I'd like to have instances of the Carrier object with the name of the carrier (ex: Carrier1) and the carriers object holding all of those so I can do something like carriers.Carrier18.getInterval() but I just cant figure out how to get instances named (thats the reason i used ArrayList). I use the arraylist to populate a jComboBox so the list is always in the same order as the carriers are. That way I can do carriers.getCarrier(jComboBox.getSelectedIndex()). getInterval() and not worry about indexes being out of sync.

Anyway, if someone has a better idea, I'd sure like to hear what you have to say. Thanks

JSon,

Thanks again for the quick reply. I had been thinking about this last night some more and was unable to post. I don't think my application should ever know the actual names of the carriers. I am designing it to be used across multiple divisions and the carriers will be different for each. Maps will be new for me and I am definitely going to see how it works out. I did not know any java at all before starting this project so it's all been one big learning experience.

You said "you could of course" in your reply. Does that mean you think my original solution was wrong and a map is a better solution or is it just an alternative. As I learn, I am trying to get better. this type of feedback helps immensely. Thanks again.