DOM Parser query in JAVA

Question

<subjectOf typeCode="SUBJ">
    <annotation classCode="ACT" moodCode="EVN">
        <realmCode code="QD" />
        <code code="SPECIALNOTE"></code>
        <text><![CDATA[<strong>** New York State approval pending. This test is not available for New York State patient testing **</br> ]]></text>
    </annotation>
</subjectOf>
<subjectOf typeCode="SUBJ">
    <annotation classCode="ACT" moodCode="EVN">
        <realmCode code="QD" />
        <code code="PREFERREDSPECIMEN"></code>
        <text><![CDATA[2 mL Second void urine <strong>or </strong>2-hour urine <strong>or </strong>&nbsp;2 mL Urine with no preservative]]></text>
    </annotation>
</subjectOf>

In DOM parsing, how can I traverse through the above XML and get the <text> tag value depending upon a <code> tag attribute having a given value. For example, I want to get the following text:

<strong>** New York State approval pending. This test is not available for New York State patient testing **</br>

...based on the <code> tag with a code attribute where value="SPECIALNOTE".

public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {      
    DocumentBuilderFactory domFactory =  DocumentBuilderFactory.newInstance();          
    domFactory.setNamespaceAware(true);      
    DocumentBuilder builder = domFactory.newDocumentBuilder();     
    Document doc = builder.parse("xml.xml");     
    XPath xpath = XPathFactory.newInstance().newXPath();        // XPath Query for showing all nodes value     

    XPathExpression expr = xpath.compile("/testCodeIdentifier/subjectOf/subjectOf/annotation/code[@code='SPECIALNOTE']");      
    Object result = expr.evaluate(doc, XPathConstants.NODESET);     
    NodeList nodes = (NodeList) result;     
    for (int i = 0; i < nodes.getLength(); i++) {      
        System.out.println("........"+nodes.item(i).getNodeValue()+"........");      
        }   
    } 
}

Appreciate the help in advance...

I downvoted your question and voted for it to be closed. It started to evolve in a really messy way, such that it is not very simple for other users to understand how it evolved. The main question here seemed to be a simple XPath question at first. Now it is no longer clear what is being asked... Please make your Stack Overflow questions simple and clear. If you run into new problems while answering the questions, open new questions, or delete this one, if it becomes obsolete — Lukas Eder
– Lukas Eder, Commented Dec 20, 2011 at 7:31

Wayne · Accepted Answer · 2011-12-19 16:59:36Z

2

First, your XPath expression has an error; subjectOf is repeated unnecessarily:

/subjectOf/subjectOf

Now, assuming you really do need a reference to the code node that precedes the target text element, then use the following:

XPathExpression expr = xpath.compile(
    "/testCodeIdentifier/subjectOf/annotation/code[@code='SPECIALNOTE']");
Node node = (Node) expr.evaluate(doc, XPathConstants.NODE);
System.out.println(getNextElementSibling(node).getTextContent());

Where getNextElementSibling is defined as follows:

public static Node getNextElementSibling(Node node) {
    Node next = node;
    do {
        next = next.getNextSibling();
    } while ((next != null) && (next.getNodeType() != Node.ELEMENT_NODE));
    return next;
}

A couple of notes about this:

The reason that getNextSibling did not originally work for you is (most likely) because the next sibling of the referenced code element is a text node, not an element node. (The whitespace between code and text is significant.) That's why we need getNextElementSibling.
We're selecting a single node, so we're using XPathConstants.NODE instead if XPathConstants.NODELIST

Note that you should probably just do as @Lukas suggests and modify your XPath expression to directly select the target text.

Here's how to get the text directly (as a String):

XPathExpression expr = xpath.compile(
    "/testCodeIdentifier/subjectOf/annotation[code/@code='SPECIALNOTE']/text/text()");
String text = (String) expr.evaluate(doc, XPathConstants.STRING);
System.out.println(text);

Here's how to first get a reference to the element and then retrieve the contents of its CDATA section:

XPathExpression expr = xpath.compile(
    "/testCodeIdentifier/subjectOf/annotation[code/@code='SPECIALNOTE']/text");
Node text = (Node) expr.evaluate(doc, XPathConstants.NODE);
System.out.println(text.getTextContent());

answered Dec 19, 2011 at 16:59

Wayne

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4 Comments

GOK Over a year ago

subjectOf is two times in my hierarchy...the above is the sample code to show how the xml looks and what i needed to show in the question to make others understand..

Wayne Over a year ago

In trying to help us understand, you only confused. We can only work with what you show us, so if what you show us doesn't match reality, then we're doomed to provide incomplete answers. In any event, my answer still stands; just put the extra subjectOf in as necessary. Have you tried the code in my answer?

GOK Over a year ago

I have incorporated it... i was not confused the above comment was only FYI. I can understand that.. i am not a dumbo...Every Solution which was given by you is much appeciated...but whenever you have called up .getTextContent() it gives me NullPointerException... i dont have any idea..but <text> tag is present...

Wayne Over a year ago

This is why you need to show your exact input and the exact code you're using. My code was tested before I answered with it. It is working on my machine. Also, @Lukas's answer should work. Clearly, there is some difference in your code that you haven't revealed.

Lukas Eder · Accepted Answer · 2011-12-20 07:27:49Z

2

Fix your XPath expression like this:

/testCodeIdentifier/subjectOf/annotation[code/@code='SPECIALNOTE']/text

You could then, for instance, access the CDATA content using

Node.getTextContent();

UPDATE: The above XPath seemed correct at the time I posted it. In the meantime, you have completely changed your XML code and now, the XPath would read

/testCodeIdentifier/subjectOf/code/subjectOf/annotation[code/@code='SPECIALNOTE']/text

Or, because I am guessing that this question is so messy, it's still wrong, just do:

//annotation[code/@code='SPECIALNOTE']/text

edited Dec 20, 2011 at 7:27

answered Dec 19, 2011 at 14:08

Lukas Eder

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6 Comments

Lukas Eder Over a year ago

@GOK: I'm sorry, I misunderstood your question. I'll fix my answer

GOK Over a year ago

Thank u for understanding my query, vry less ppl get to that pt...:)

GOK Over a year ago

for (int i = 0; i < nodes.getLength(); i++) { System.out.println("aaaaa"); System.out.println("........"+nodes.item(i).getTextContent()+"........"); } Did i did correct ?? i think the current one is <code> tag we need to get the <text> tag info... can i have the syntax to access the next tag..i know nextsibling() but its not helpful..

Wayne Over a year ago

"its not doing it" is not a helpful statement. You can edit your question to show exactly what input you're using and exactly what code you tried and exactly what output you received and exactly what output you expected. That is how a good question is written.

GOK Over a year ago

@lwburk I have updated the exact code replica to make u understand whats i need and when i run this program it gives me a error as : Exception in thread "main" java.lang.NullPointerException at com.parse.demo.getNextElementSibling(demo.java:26) at com.parse.demo.main(demo.java:20)

|

GOK · Accepted Answer · 2011-12-20 11:14:05Z

-1

Finally i have got the answer for my question by myself.... Below code is being working for my XML to be parsed...

  XPath xpath = XPathFactory.newInstance().newXPath();
   // XPath Query for showing all nodes value
  XPathExpression expr = xpath.compile("//testCodeIdentifier/subjectOf/order/subjectOf/annotation/code[@code='SPECIALNOTE']/following-sibling::text/text()");

  Object result = expr.evaluate(doc, XPathConstants.NODESET);
  NodeList nodes = (NodeList) result;
  for (int i = 0; i < nodes.getLength(); i++) {

      System.out.println(nodes.item(i).getNodeValue()); 

  }

Thank you people who have ansewered in this post but this is a possible solution for it. Have a mark on it.

answered Dec 20, 2011 at 11:14

GOK

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