Provide a virtual node structure for unavailable nodes.

[mathieucarbou]

Reported by christopher.klewes, Apr 20, 2011
First I would like to say thanks for your framework. It's really nice and I'm loving to create XML documents with it.

I recently wanted to read from a XML file which has many optional elements and therefore can occure very differing. I stumbled upon #gotoChild(String xPath) which enables the traversal to a specific child. This is really great but unfortunately it throws an Exception if this child doesn't exists. So I found the #hasTag(String xPath) method which can check this. This works great but bloats up my code extremely.

For example I have the following XML document with the root "user" and the element "name" but it also could optionally contain "login" and "password".

  <user>
    <name>moo</name>
  </foo>

To check this the code would look like

  if(user.hasTag("name")) 
  {
     String name = user.gotoChild("name").getText()
  }

  if(user.hasTag("login")) 
  {
     String login = user.gotoChild("login").getText()
  }

[...]
... and so on!

I would like to have something like Groovys XML slurper. It provides unavaiable nodes/tags if you try to traverse to structured which aren't available.

The code could look like this:

String name = user.gotoChild("name").getText()

Instead of throwing a exception here you could collect the state and return an unavailable tag which returns null on the .getText() call. Also if we try to do something like this:

XMLTag address = user.gotoChild("address")

String street = address.gotoChild("street").getText()

Could also work if you provide a unavailable tag which results null in case of unfound structures.

What do you think?

Hope to hear from you!

Best Regards
Chris
Jun 14, 2011 Delete comment Project Member #1 mathieu.carbou
Yes, I also think that having a null object is a very good idea !!