Re: [dom4j-user] Asking again - Does node exist

[Christian Niles]

Then XPath is your best bet. You'll want to pre-compile any XPaths you 
intend to keep around for awhile to save from parsing the string all 
the time. You might look at directly using the Jaxen interfaces, since 
they have some more specific functions, such as XPath.booleanValueOf(). 
I'm not sure that these are any more performant than selectNodes(), but 
may be clearer in your code.

best,
christian.
On Wednesday, November 19, 2003, at 03:59  PM, david wrote:

We need this for arbitrary nodes that are entered at runtime.

---------- Original Message ----------------------------------
From: Christian Niles <[EMAIL PROTECTED]>
Date:  Wed, 19 Nov 2003 15:39:12 -0500
To risk stating the obvious, you look for the node ;) In essence, 
you'd
just hand-code the XPath using the DOM4J methods such as
Element.element(String).

So, to search for the /html/head element,

Document doc = new SAXReader().read("http://www.dom4j.org/";);
Element htmlElem = doc.getRootElement();
Element headElem = htmlElem.element("head");
if (headElem != null) {
        // node exists
}
This is more efficient, but requires you to know the document 
structure
beforehand. Use XPath to either save yourself coding when performance
isn't an issue, or when you need to be able to search for an arbitrary
node.

christian.

On Wednesday, November 19, 2003, at 12:39  AM, David Thielen wrote:

 

----- Original Message -----
From: David Thielen
To: [EMAIL PROTECTED]
Sent: Sunday, November 16, 2003 2:59 PM
Subject: Re: [dom4j-user] [dom4j] - Does node exist
Actually this doesn't always work either. The best I have some up 
with
is:
 
    node.selectNodes(text).size() > 0
 
which I am assuming is not very efficient.
 
Is there a better way????
 
thanks - dave
 
 

----- Original Message -----
From: David Thielen
To: [EMAIL PROTECTED]
Sent: Sunday, November 16, 2003 1:45 PM
Subject: [dom4j-user] [dom4j] - Does node exist
Hi;
 
What is the most efficient way to determine if a node exists. The 
only
way I have founs so far is:
 
if (node.matches(text))
 
where text is the xpath to the node I am looking for and node is a
Node I start the search from.
 
thanks - dave






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