Re: getAttribute()

[Nigel S. <nig...@us...>]

Don't seem to have a record of replying to this...

> I put my little own getAttribute() function in the class. Did I miss
> something or is there really only getAttributes(), and if there's no
> attribute of that kind available it causes an error? That were my
experience
> with v2.20. Well I use a DTD to my XML that even expands some attributes
to
> a value if none is given but I guess DTDs aren't parsed.

Version 3 only has a getAttributes() function, but it has an optional
parameter that turns it into a getAttribute() function.

DTDs aren't parsed.  Have observed that this is a deficiency, wasn't sure
how important it was to our users.  Not sure how complex it would be to
parse and use either.

Comments?

> Another question, how can/ should I comment the class now that I did a
> little change? I tried to scan the mozilla license for some information. I
> hope it's not illegal to redistribute the class inside my package (it's
not
> the core, I just use it for the free QML-interpreter at
> http://questml.com ).

Comment it?  Well in the JavaDoc style:
http://java.sun.com/j2se/javadoc/writingdoccomments/index.html and you
should label yourself as the author using the @author tag.

> My own function actually returns not null but an empty string if the
> attribute is not found, which I think is not really standard but very nice
> for my own purpoes. Now in case it's not a workaround for something that's
> already in the class here goes my source (just as reference with no intend
> to have it in any "official" version).
>
>     function getAttribute($absoluteXPath, $attributeName)
>     {
>         $attributeValue = "";
>         $attributes = $this->getAttributes($absoluteXPath);
>         foreach ($attributes as $key => $value)
>         {
>             if ($key == $attributeName && $attributeValue == "")
>                 $attributeValue = $value;
>         }
>
>         return $attributeValue;
>     }

I think that the Php.XPath class should stick to returning an unset value if
the attribute is not set.   It probably makes for a more useful function.
You can use the empty() and isset() functions to determine the state of the
return value, but I agree that it might be a little annoying to use.

What you could do is create a Php.XPath "wrapper" and overwrite the supplied
getAttributes() function that handles errors and nulls in the way you want
it too.  I think that would be the best idea.  ie.

class MyXPath extends XPath {
  // My overridden version of getAttributes.  Means return value is ""
instead of null.
  function getAttributes($absoluteXPath, $attrName=NULL) {
    $ret = parent::getAttributes($absoluteXPath, $attrName);
    if (!$ret) return "";
    return $ret;
  }
}

Cheers

Nigel