BlackBerry/J2ME - SAX parse collection of objects with attributes

Answer 1

package com.ahoy.utils;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.Vector;
import net.rim.device.api.xml.parsers.ParserConfigurationException;
import net.rim.device.api.xml.parsers.SAXParser;
import net.rim.device.api.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import com.ahoy.bean.DealData;

public class XMLDealsParser extends DefaultHandler  {

    boolean currentElement = false;
    String currentValue = null;
    DealData currentDealData = null;
    String previousNodeName = new String("nil");
    public Vector dealVector = new Vector(5);
    //public static Vector geoDataItems = null;
    public XMLDealsParser(String data){
        InputStream inputStream=null;
        SAXParser sp;
        try {
            inputStream = new ByteArrayInputStream(data.getBytes());
            SAXParserFactory spf = SAXParserFactory.newInstance();

            sp = spf.newSAXParser();

            sp.parse(inputStream, this);
        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            Logger.error(" -------XMLDealsParser  >> XMLDealsParser() ",e);

            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            Logger.error(" -------XMLDealsParser  >> XMLDealsParser() ",e);
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            Logger.error(" -------XMLDealsParser  >> XMLDealsParser() ",e);
            e.printStackTrace();
        }
    }

    public Vector getDealList() {
        return dealVector;
    }

    public void setDealList(Vector dealList) {
        this.dealVector = dealList;
    }

    /** Called when tag starts ( ex:- <name>AndroidPeople</name> 
     * -- <name> )*/
    public void startElement(String uri, String localName, String qName,
            Attributes attributes) throws SAXException {

        currentElement = true;

        if (localName.equals("deal"))
        {
            /** Start */ 
            this.currentDealData = new DealData();

        }if (localName.equals("id"))
        {
            /** Start */
        }
    }

    /** Called when tag closing ( ex:- <name>AndroidPeople</name> 
     * -- </name> )*/
    public void endElement(String uri, String localName, String qName)
            throws SAXException {

        currentElement = true;

        /** set value */ 
        if (localName.equalsIgnoreCase("deal"))
        {
            dealVector.addElement(currentDealData);
            return;
        }
        if (localName.equalsIgnoreCase("id"))
        {
            currentDealData.id = currentValue;
        }else if (localName.equalsIgnoreCase("score"))
        {
            currentDealData.score = currentValue;
        }else if (localName.equalsIgnoreCase("shortDescription"))
        {
            currentDealData.shortDescription = currentValue;
        }
        //dealVector.addElement(currentGeoData);
        System.out.println("dealVector.size():"+ dealVector.size());
    }

    /** Called to get tag characters ( ex:- <name>AndroidPeople</name> 
     * -- to get AndroidPeople Character ) */
    public void characters(char[] ch, int start, int length)
            throws SAXException {

        if (currentElement) {
            currentValue = new String(ch, start, length);
            System.out.println("DATA: " + currentValue);
            currentElement = false;
        }
    }

    public void callback(String data) throws Exception {
        // TODO Auto-generated method stub

    }
}

Answer 2

UPDATE updated to skip span and concat values from fields with same name

Hi! I would suggest to use hashtable to handle those "fields":

class XMLObject {
    private Hashtable mFields = new Hashtable();
    private int mN = -1;

    public int getN() {
        return mN;
    }

    public void setN(int n) {
        mN = n;
    }

    public boolean isFieldExist(String key)
    {
        return mFields.containsKey(key);
    }

    public String getStringField(String key) {
        return (String) mFields.get(key);
    }

    public void setStringField(String key, String value) {
        mFields.put(key, value);
    }

    public String getPID() {
        return getStringField("PID");
    }

    public void setPID(String pid) {
        setStringField("PID", pid);
    }

    public String getDcCoverage() {
        return getStringField("dc.coverage");
    }

    public void setDcCoverage(String dcCoverage) {
        setStringField("dc.coverage", dcCoverage);
    }

    public String getFgsOwnerId() {
        return getStringField("fgs.ownerId");
    }

    public void setFgsOwnerId(String fgsOwnerId) {
        setStringField("fgs.ownerId", fgsOwnerId);
    }

    public String dccreator() {
        return getStringField("dc.creator");
    }

    public void dccreator(String dccreator) {
        setStringField("dc.creator", dccreator);
    }

    public String getdcformat() {
        return getStringField("dc.format");
    }

    public void setdcformat(String dcformat) {
        setStringField("dc.format", dcformat);
    }

    public String getdcidentifier() {
        return getStringField("dc.identifier");
    }

    public void setdcidentifier(String dcidentifier) {
        setStringField("dc.identifier", dcidentifier);
    }

    public String getdclanguage() {
        return getStringField("dc.language");
    }

    public void setdclanguage(String dclanguage) {
        setStringField("dc.language", dclanguage);
    }

    public String getdcpublisher() {
        return getStringField("dc.publisher");
    }

    public void setdcpublisher(String dcpublisher) {
        setStringField("dc.publisher", dcpublisher);
    }

    public String getdcsubject() {
        return getStringField("dc.subject");
    }

    public void setdcsubject(String dcsubject) {
        setStringField("dc.subject", dcsubject);
    }

    public String getdctitle() {
        return getStringField("dc.title");
    }

    public void setdctitle(String dctitle) {
        setStringField("dc.title", dctitle);
    }

    public String getdctype() {
        return getStringField("dc.type");
    }

    public void setdctype(String dctype) {
        setStringField("dc.type", dctype);
    }

    public String toString() {
        StringBuffer sb = new StringBuffer();
        sb.append("N:" + mN + ";");
        Enumeration keys = mFields.keys();
        while (keys.hasMoreElements()) {
            String key = (String) keys.nextElement();
            sb.append(key + ":" + mFields.get(key) + ";\n");
        }
        return sb.toString();
    }
}

Then in handler you will not have to set some specific class member, just put value using "name" attribute as a key:

class XMLObjectHandler extends DefaultHandler {
    private String mCurrentTag = "";
    private String mCurrentText = "";
    private Attributes mCurrentAttr = null;
    private XMLObject[] mXMLObjects = new XMLObject[] {};
    private XMLObject mCurrentXMLObject = new XMLObject();
    private boolean mIgnoreTag = false;

    public XMLObject[] getXMLObjects() {
        return mXMLObjects;
    }

    public void startElement(String uri, String localName, String name,
            Attributes attributes) throws SAXException {
        mIgnoreTag = mCurrentTag.equalsIgnoreCase("field")
                && name.equalsIgnoreCase("span");

        if (!mIgnoreTag) {
            mCurrentTag = name;
            mCurrentAttr = attributes;
        } else {
            mCurrentText += " ";
        }
        if (mCurrentTag.equalsIgnoreCase("object")) {
            mCurrentXMLObject = new XMLObject();
            mCurrentXMLObject.setN(Integer
                    .parseInt(mCurrentAttr.getValue("no")));
        }
    }

    public void characters(char[] ch, int start, int length)
            throws SAXException {
        if (mCurrentTag.equalsIgnoreCase("field"))
            mCurrentText = mCurrentText.concat(new String(ch, start, length));
    }

    public void endElement(String uri, String localName, String name)
            throws SAXException {
        if (name.equalsIgnoreCase("field")) {
            String fieldName = mCurrentAttr.getValue("name");
            if(mCurrentXMLObject.isFieldExist(fieldName))
            {
                mCurrentText = mCurrentXMLObject.getStringField(fieldName) 
                                + " " + mCurrentText;
            }           
            mCurrentXMLObject.setStringField(fieldName, mCurrentText);
        } else if (name.equalsIgnoreCase("object")) {
            Arrays.add(mXMLObjects, mCurrentXMLObject);
        }
        if (!mIgnoreTag) {
            mCurrentTag = "";
            mCurrentText = "";
        } else {
            mCurrentText += " ";
        }
    }
}

See sample usage:

    public Scr() {
        StringBuffer sb = new StringBuffer();
        sb.append("<Objects>");
        sb.append("<Object no=\"1\">");
        sb
                .append("<field name=\"PID\">ilives:87877</field>"+
            "<field name=\"dc.coverage\">Charlottetown</field>"+
            "<field name=\"fgs.ownerId\">fedoraAdmin</field>");
        sb.append("</Object>");
        sb.append("<Object no=\"2\">");
        sb
                .append("<field name=\"PID\">ilives:87878</field>"+
            "<field name=\"dc.coverage\">Rimston</field>"+
            "<field name=\"fgs.ownerId\">jamesAdmin</field>");
        sb.append("</Object>");
        sb.append("</Objects>");

        String xml = sb.toString();
        ByteArrayInputStream bais = 
            new ByteArrayInputStream(xml.getBytes());       
        XMLObject[] xmlObjects = getXMLObjects(bais);
        for (int i = 0; i < xmlObjects.length; i++) {
            XMLObject o = xmlObjects[i];
            add(new LabelField(o.toString()));
        }
    }

    static XMLObject[] getXMLObjects(InputStream is) {
        XMLObjectHandler xmlObjectHandler = new XMLObjectHandler();
            try {
                SAXParser parser = SAXParserFactory.newInstance()
                        .newSAXParser();
                parser.parse(is, xmlObjectHandler);
            } catch (ParserConfigurationException e) {
                e.printStackTrace();
            } catch (SAXException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        return xmlObjectHandler.getXMLObjects();
    }
}

alt text http://img441.imageshack.us/img441/1372/saxj.jpg

PS If there will be performance issues (say having over 1000 xml objects) just replace hashtable with class members and update handler accordingly...