Displaying message at empty node in blackberry xml parsing - blackberry

Question

In parsing an XML result in a blackberry application, which returns nodes in the form;
<searches>
<search id ='1234'>
<name> somename </name>
<address> some address </address>
<sector> some sector </sector>
<contacts> 12345, me#me.com </contacts>
<searches>
when a search is made which doesn't have any matches the result is returned empty, that is;
<name></name>
<address></address>
<sector></sector>
<contacts></contacts>
don't return with the results. It appears just as <searches></searches> . How do I specify a dialog alert in such cases when the search results return just <searches></searches>
here is my Http connection attached with the parser.
try{
HttpConnection connection = (HttpConnection)Connector.open("http://someurl.xml",Connector.READ_WRITE);
URLEncodedPostData postData = new URLEncodedPostData(URLEncodedPostData.DEFAULT_CHARSET, false);
postData.append("username", "someusername");
postData.append("password", "somepassword");
postData.append("term", word);
connection.setRequestMethod(HttpConnection.POST);
connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
connection.setRequestProperty("User-Agent","Profile/MIDP-2.0 Configuration/CLDC-1.0");
OutputStream requestOut = connection.openOutputStream();
requestOut.write(postData.getBytes());
connection.getHeaderField("Content-type");
DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
docBuilder.isValidating();
InputStream detailIn = connection.openInputStream();
doc = docBuilder.parse(detailIn);
requestOut.close();
connection.close();
NodeList list = doc.getElementsByTagName("name");
NodeList list1 = doc.getElementsByTagName("address");
NodeList list2 = doc.getElementsByTagName("sector");
NodeList list3 = doc.getElementsByTagName("contacts");
callback(list,list1,list2,list3);
requestOut.close();
connection.close();
}
catch(Exception ex){
System.out.println(ex.toString());
}
do I use if's or for ?

Answer 1

I don't have the Eclipse plug-in in front of me (so I can't test this code), but something like this should work:
doc = docBuilder.parse(detailIn);
requestOut.close();
connection.close();
NodeList list = doc.getElementsByTagName("name");
NodeList list1 = doc.getElementsByTagName("address");
NodeList list2 = doc.getElementsByTagName("sector");
NodeList list3 = doc.getElementsByTagName("contacts");
if (list == null || list.getLength() == 0) {
// no results, so post an alert on the UI thread
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
Dialog.alert("No results found!");
}
});
}
This only tests the existence of the name element, assuming that if name is missing, so will the others (address, sector, and contacts). If that's not true for your application, you could choose to make the if statement check list1, list2, and list3 also.