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Looking for a specific child in XML using java

I've been looking for the past few hours, and I can't find how to do it.
My XML file:
<list>
<Company id="01">
<Name>Atari</Name>
<Founded>1972</Founded>
<Consoles>
2600
5200
7800
</Consoles>
</Company>
<Company id="02">
<Name>Sega</Name>
<Founded>1960</Founded>
<Consoles>
Master System
Megadrive
Saturn
</Consoles>
</Company>
</list>
Basically, I want the code to find not only the name in one company block, but the name in any company block I wish, and be able to show it to other classes. So far, I've been able to show either or, but only by changing the code directly and not on the fly. The code I'm using:
private static String getTextValue(String def, Element doc, String tag) {
String value = def;
NodeList nl;
nl = doc.getElementsByTagName(tag);
if (nl.getLength() > 0 && nl.item(0).hasChildNodes()) {
value = nl.item(0).getFirstChild().getNodeValue();
}
if(value==null) value = " ";
return value;
}
public static boolean readXML(String xml) {
rolev = new ArrayList<String>();
Document dom;
// Make an instance of the DocumentBuilderFactory
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
// use the factory to take an instance of the document builder
DocumentBuilder db = dbf.newDocumentBuilder();
// parse using the builder to get the DOM mapping of the
// XML file
dom = db.parse(xml);
Element doc = dom.getDocumentElement();
role1 = getTextValue(role1, doc, "Name");
if (getRole1() != null) {
if (!getRole1().isEmpty())
rolev.add(getRole1());
}
role2 = getTextValue(role2, doc, "Founded");
if (role2 != null) {
if (!role2.isEmpty())
rolev.add(role2);
}
role3 = getTextValue(role3, doc, "Consoles");
if (role3 != null) {
if (!role3.isEmpty())
rolev.add(role3);
}
role4 = getTextValue(role4, doc, "Name");
if ( role4 != null) {
if (!role4.isEmpty())
rolev.add(role4);
}
return true;
} catch (ParserConfigurationException pce) {
System.out.println(pce.getMessage());
} catch (SAXException se) {
System.out.println(se.getMessage());
} catch (IOException ioe) {
System.err.println(ioe.getMessage());
}
return false;
}
I used a lot of different methods, some searched up and some made on my own, but this one is the closest I can get to working for what I need. I need to be able to have the place it's looking change on the fly though.

You can use xpath to read XML. See Parsing XML with XPath in Java and/or How to read XML using XPath in Java
In your case, if you wanted to get all of the company names the set path you would use (basically the tag filter) would be "//list/Company/Name/text()"
The rest of the code can basically be copied from the questions I posted. Only your set (filter) would be different.

number´s of parse strings from xml

i have a little question :).My problem is , that i parse a xml and make by every tag there are parsing a new fragment. .But now my problem:
By creating Tabs i must give the FragmentPagerAdapter the numbers of tabs there he must creating.I downt know why i can give him they without array list.Thats the code there say how much tabs he must creating.Normaly it locks like
public final String[] titles = {"123", "123"}; but now i parse it to a string without array.
#Override
public int getCount() {
return Names.length();
}
but this isnt posible with Strings, so my question can anybody can tell me a solution on there i can give him a number of the tags from the xml there he have parse.
the xml:
<rooms>
<room>
<roomname>Wohnzimmer</roomname>
<devices>
<device>
<deviceid>1</deviceid>
<devicename>some name</devicename>
<action1>3</action1>
<action2>4</action2>
<devicetype>some name</devicetype>
<text1>1</text1>
<text2>2</text2>
</device>
</devices>
</room>
<room>
<roomname>Wohnzimmer</roomname>
<devices>
<device>
<deviceid>1</deviceid>
<devicename>some name</devicename>
<action1>3</action1>
<action2>4</action2>
<devicetype>some name</devicetype>
<text1>1</text1>
<text2>2</text2>
</device>
</devices>
</room>
</rooms>
i need the childs there are the xml parser parse from the category rooms(the childs from the tag rooms).i want to count the tags there the rooms tag have. in this case its are 2.
My code looks now so:
#Override
public int getCount() {
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document dom = db.parse("employees.xml");
Element element = (Element) dom.getElementsByTagName("app_type").item(0);
NodeList nodes = dom.getElementsByTagName("tagName");
int count = nodes.getLength();
}
catch (ParserConfigurationException pce) {
pce.printStackTrace();
}
catch (IOException ioe) {
ioe.printStackTrace();
}
catch (SAXException sae) {
sae.printStackTrace();
}
return count;
}
but i get a error on count he cant resolve count.

What I understood you have an xml and you are looking to parse few tags out of that xml, you can use XML java API
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document dom = db.parse("employees.xml");
Element element = (Element) dom.getElementsByTagName("app_type").item(0);
NodeList nodes = dom.getElementsByTagName('"tagName");
int count = nodes.getLength();
Dont forget to put this in try catch block as this API throws exceptions.
Cheers !!

XML Parsing using DocumentBuilder

I am trying to parse a xml into a map of key-value pairs as follows.
Sample xml document:
<Students>
<StudentA>
<Id>123</Id>
<Address>123 W </Address>
<Courses>
<Course1>CS203</Course1>
<Course2>CS206</Course2>
</Courses>
</StudentA>
<StudentB>
<Id>124</Id>
<Address>124 W </Address>
<Courses>
<Course1>CS202</Course1>
<Course2>CS204</Course2>
</Courses>
</StudentB>
</Students>
The xml parser code:
/**
* Parse the given xml data.
* #param xmlString The xml string to be parsed.
* #return Non-null list of {#link DiscreteDataEntry} values, may be empty.
*/
Map<String, String> parseXML(final String xmlString)
{
final String xmlDataToParse = xmlString;
parentNode = "";
try
{
final InputStream inputStream = new ByteArrayInputStream(xmlDataToParse.getBytes());
final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setNamespaceAware(true);
final DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
final Document document = documentBuilder.parse(inputStream);
final Map<String, String> data = createMapOfAttributeValuesKeyedByName(document.getDocumentElement());
}
catch (final Exception exception)
{
System.out.println("Exception:" + exception);
}
return data;
}
/**
* A recursive method which will loop through all the xml nodes.
* #param node The node.
* #return Non-null map of test values keyed by test name, may be empty.
*/
Map<String, String> createMapOfAttributeValuesKeyedByName(final Node node)
{
final Map<String, String> attributeValuesKeyedByName = new LinkedHashMap<String, String>();
final NodeList nodeList = node.getChildNodes();
for (int index = 0; index < nodeList.getLength(); index++)
{
final Node currentNode = nodeList.item(index);
if (node.getFirstChild() != null && node.getFirstChild().getNodeType() == Node.ELEMENT_NODE)
{
parentNode = getAncestralOrigin(currentNode);
attributeValuesKeyedByName.putAll(createMapOfAttributeValuesKeyedByName(currentNode));
}
else if (node.getFirstChild() != null && node.getFirstChild().getNodeType() == Node.TEXT_NODE)
{
final String attributeName = parentNode.length() > 0 ? parentNode + "." + node.getNodeName().trim() : node.getNodeName().trim();
final String attributeValue = node.getTextContent().trim();
attributeValuesKeyedByName.put(attributeName, attributeValue);
parentNode = "";
}
}
return attributeValuesKeyedByName;
}
/**
* Parses a give node and finds all its ancestors.
* #param node The node whose ancestors have to be found.
* #return A non-null but possible empty string built using the ancestors of the node.
*/
final String getAncestralOrigin(final Node node)
{
String ancestralOrigin = "";
final Node currentParentNode = node.getParentNode();
if (currentParentNode != null && currentParentNode.getNodeType() != Node.DOCUMENT_NODE)
{
ancestralOrigin = currentParentNode.getNodeName();
final String ancestor = getAncestralOrigin(currentParentNode);
if (ancestor.length() > 0)
{
ancestralOrigin = ancestor + "." + ancestralOrigin;
}
}
return ancestralOrigin;
}
The output of the map is :
Key:[Students.StudentA.Id], Value:[123]
Key:[Students.StudentA.Address], Value:[123 W]
Key:[Students.StudentA.Courses.Course1], Value:[CS203]
Key:[Students.StudentA.Courses.Course2], Value:[CS206]
Key:[Students.StudentB.Id], Value:[124]
Key:[Students.StudentB.Address], Value:[124 W]
Key:[Students.StudentB.Courses.Course1], Value:[CS202]
Key:[Students.StudentB.Courses.Course2], Value:[CS204]
But this output works fine if the file is being read with
final BufferedReader bufferedReader = new BufferedReader(new FileReader(new File(url.getFile().replaceAll("%20", " "))));
if the same file is read with
DataInputStream is = new DataInputStream(new FileInputStream(new File(url.getFile().replaceAll("%20", " "))));
the output is different. It does take all CR and LF within the xml doc.
Key:[Students], Value:[123
123 W
CS203
CS206
124
124 W
CS202
CS204]
I am using a dependency jar to read xml file which uses DataInputStream.
I was always under the impression that my xml parsers would take care of CR/LF/NewLine looks like its not.
I am replacing all CR LF and NewLines with empty string before parsing it.
But I would like to know if there are other xml parsers which would take care of itself. Also what is the reason behind BufferedReader skipping CR/LF and NewLine
but where as DataInputStream would not.
Also Is there any other better way to find the ancestors of the child tag, I need them to make the key value unique.
The xml will be as it is and cannot be changed. Also the xml will not be same as being shown here, it will be a generic xml with tags
changing, so I am trying to make a generic xml parser that parses xml child tags and puts them into a map.
The child tags can be duplicated so, I am using the path to the child to make it unique.
Also is there a way to parse the xml with just these tags(StudentA/StudentB) recursively by removing parent tag Students.
Note: The xml format changes and xml that I parse might be changing for every xml file.
So I really can't parse like get children of StudentA.

After go through long description, I learn that, you want to know other better way to parse XML.
The answer is, Yes, there are some other better way to parse XML. Use StAX or SAX, these are fast and more memory efficient. To learn more read JAXP of Java Tutorial.

DataInputStream is intended to read only something written using a DataOutputStream... i.e. serialized Java objects. It is not intended for reading text input.

Xml document to DOM object using DocumentBuilderFactory

I am currently modifying a piece of code and I am wondering if the way the XML is formatted (tabs and spacing) will affect the way in which it is parsed into the DocumentBuilderFactory class.
In essence the question is...can I pass a big long string with no spacing into the DocumentBuilderFactory or does it need to be formatted in some way?
Thanks in advance, included below is the Class definition from Oracles website.
Class DocumentBuilderFactory
"Defines a factory API that enables applications to obtain a parser that produces DOM object trees from XML documents. "

The documents will be different. Tabs and new lines will be converted into text nodes. You can eliminate these using the following method on DocumentBuilderFactory:
http://download.oracle.com/javase/6/docs/api/javax/xml/parsers/DocumentBuilderFactory.html#setIgnoringElementContentWhitespace(boolean)
But in order for it to work you must set up your DOM parser to validate the content against a DTD or xml schema.
Alternatively you could programmatically remove the extra whitespace yourself using something like the following:
public static void removeEmptyTextNodes(Node node) {
NodeList nodeList = node.getChildNodes();
Node childNode;
for (int x = nodeList.getLength() - 1; x >= 0; x--) {
childNode = nodeList.item(x);
if (childNode.getNodeType() == Node.TEXT_NODE) {
if (childNode.getNodeValue().trim().equals("")) {
node.removeChild(childNode);
}
} else if (childNode.getNodeType() == Node.ELEMENT_NODE) {
removeEmptyTextNodes(childNode);
}
}
}

It should not affect the ability of the parser as long as the string is valid XML. Tabs and newlines are stripped out or ignored by parsers and are really for the aesthetics of the human reader.
Note you will have to pass in an input stream (StringBufferInputStream for example) to the DocumentBuilder as the string version of parse assumes it is a URI to the XML.

The DocumentBuilder builds different DOM objects for xml string with line feeds and xml string without line feeds. Here is the code I tested:
StringBuilder sb = new StringBuilder();
sb.append("<root>").append(newlineChar).append("<A>").append("</A>").append(newlineChar).append("<B>tagB").append("</B>").append("</root>");
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
InputStream xmlInput = new ByteArrayInputStream(sb.toString().getBytes());
Element documentRoot = builder.parse(xmlInput).getDocumentElement();
NodeList nodes = documentRoot.getChildNodes();
System.out.println("How many children does the root have? => "nodes.getLength());
for(int index = 0; index < nodes.getLength(); index++){
System.out.println(nodes.item(index).getLocalName());
}
Output:
How many children does the root have? => 4
null
A
null
B
But if the new newlineChar is removed from the StringBuilder,
the ouptput is:
How many children does the root have? => 2
A
B
This demonstrates that the DOM objects generated by DocumentBuilder are different.

There shouldn't be any effect regarding the format of the XML-String, but I can remember a strange problem, as I passed a long String to an XML parser. The paser was unable to parse a XML-File as it was written all in one long line.
It may be better if you insert line-breaks, in that kind, that the lines wold not be longer than, lets say 1000 bytes.
But sadly i do neigther remember why that error occured nor which parser I took.

How do you traverse and store XML in Blackberry Java app?

I'm having a problem accessing the contents of an XML document.
My goal is this:
Take an XML source and parse it into a fair equivalent of an associative array, then store it as a persistable object.
the xml is pretty simple:
<root>
<element>
<category_id>1</category_id>
<name>Cars</name>
</element>
<element>
<category_id>2</category_id>
<name>Boats</name>
</element>
</root>
Basic java class below. I'm pretty much just calling save(xml) after http response above. Yes, the xml is properly formatted.
import java.io.IOException;
import java.util.Hashtable;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.util.Vector;
import net.rim.device.api.system.PersistentObject;
import net.rim.device.api.system.PersistentStore;
import net.rim.device.api.xml.parsers.DocumentBuilder;
import net.rim.device.api.xml.parsers.DocumentBuilderFactory;
public class database{
private static PersistentObject storeVenue;
static final long key = 0x2ba5f8081f7ef332L;
public Hashtable hashtable;
public Vector venue_list;
String _node,_element;
public database()
{
storeVenue = PersistentStore.getPersistentObject(key);
}
public void save(Document xml)
{
venue_list = new Vector();
storeVenue.setContents(venue_list);
Hashtable categories = new Hashtable();
try{
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory. newInstance();
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
docBuilder.isValidating();
xml.getDocumentElement ().normalize ();
NodeList list=xml.getElementsByTagName("*");
_node=new String();
_element = new String();
for (int i=0;i<list.getLength();i++){
Node value=list.item(i).getChildNodes().item(0);
_node=list.item(i).getNodeName();
_element=value.getNodeValue();
categories.put(_element, _node);
}
}
catch (Exception e){
System.out.println(e.toString());
}
venue_list.addElement(categories);
storeVenue.commit();
}
The code above is the work in progress, and is most likely heavily flawed. However, I have been at this for days now. I can never seem to get all child nodes, or the name / value pair.
When I print out the vector as a string, I usually end up with results like this:
[{ = root, = element}]
and that's it. No "category_id", no "name"
Ideally, I would end up with something like
[{1 = cars, 2 = boats}]
Any help is appreciated.
Thanks

Here's a fixed version of your program. Changes that I made are as follows:
I removed the DocBuilder-stuff from the save() method. These calls are needed to construct a new Document. Once you have such an object (and you do since it is passed in as an argument) you don't need the DocumentBuilder anymore. A proper use of DocumentBuilder is illustrated in the main method, below.
_node,_element need not be fields. They get new values with each pass through the loop inside save so I made them local variables. In addition I changed their names to category and name to reflect their association with the elements in the XML document.
There's never a need to create a new String object by using new String(). A simple "" in enough (see the initialization of the category and name variables).
Instead of looping over everything (via "*") the loop now iterates over element elements. Then there is a an inner loop that iterates over the children of each element, namely: its category_id and name elements.
In each pass of the inner we set either the category or the name variable depending on the name of the node at hand.
The actual value that is set to these variables is obtained by via node.getTextContent() which returns the stuff between the node's enclosing tags.
class database:
public class database {
private static PersistentObject storeVenue;
static final long key = 0x2ba5f8081f7ef332L;
public Hashtable hashtable;
public Vector venue_list;
public database() {
storeVenue = PersistentStore.getPersistentObject(key);
}
public void save(Document xml) {
venue_list = new Vector();
storeVenue.setContents(venue_list);
Hashtable categories = new Hashtable();
try {
xml.getDocumentElement().normalize();
NodeList list = xml.getElementsByTagName("element");
for (int i = 0; i < list.getLength(); i++) {
String category = "";
String name = "";
NodeList children = list.item(i).getChildNodes();
for(int j = 0; j < children.getLength(); ++j)
{
Node n = children.item(j);
if("category_id".equals(n.getNodeName()))
category = n.getTextContent();
else if("name".equals(n.getNodeName()))
name = n.getTextContent();
}
categories.put(category, name);
System.out.println("category=" + category + "; name=" + name);
}
} catch (Exception e) {
System.out.println(e.toString());
}
venue_list.addElement(categories);
storeVenue.commit();
}
}
Here's a main method:
public static void main(String[] args) throws Exception {
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
.newInstance();
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
docBuilder.isValidating();
Document xml = docBuilder.parse(new File("input.xml"));
database db = new database();
db.save(xml);
}

Thank you so much. With only slight modification I was able to do exactly what I was looking for.
Here are the modifications I had to do:
Even though I am building in 1.5, getTextContent was not available. I had to use category = n.getFirstChild().getNodeValue(); to obtain the value of each node. Though there may have been a simple solution like updating my build settings, I am not familiar enough with BB requirements to know when it is safe to stray from the default recommended build settings.
In the main, I had to alter this line:
Document xml = docBuilder.parse(new File("input.xml"));
so that it was reading from an InputStream delivered from my web server, and not necessarily a local file - even though I wonder if storing the xml local would be more efficient than storing a vector full of hash tables.
...
InputStream responseData = connection.openInputStream();
Document xmlParsed = docBuilder.parse(result);
Obviously I skipped over the HTTP connection portion for the sake of keeping this readable.
Your help has saved me a full weekend of blind debugging. Thank you very much! Hopefully this post will help someone else as well.

//res/xml/input.xml
private static String _xmlFileName = "/xml/input.xml";
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
InputStream inputStream = getClass().getResourceAsStream( _xmlFileName );
Document document = builder.parse( inputStream );