DOMCatagory

If you do any XML processing then I suggest you try DOMCategory in Groovy. A 'category' itself is feature of the Groovy language, borrowed from the objective C language. The short of it is you can use 'category' classes to wrap a given piece of your code. The objects in the wrapped code then gain new abilities! So what about DOMCatetgory (DOMcat)? This category allows you to work with DOM objects using a simple syntax. So an example would help. Let me first show a simple XML document then I will give a short script that can parse some values from the document.

Here is a real piece of XML I have dealt with. You can see its complexity is more than basic. It contains the namespace 'soap' which maps to http://www.w3.org/2003/05/soap-envelope, and also there are namespaces with values of urn:zimbraAdmin and urn:zimbra. For sake of ease lets say this file is named "zimbra.xml" and is found at the root ('/') of the file system.

<?xml version="1.0"?>
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
<soap:Header>
<context xmlns="urn:zimbra">
 <sessionId id="467" type="admin">467</sessionId>
 <change token="8"/>
</context>
</soap:Header>
<soap:Body>
<GetAllDistributionListsResponse xmlns="urn:zimbraAdmin">
 <dl id="b5d362c5-ef95-4fce-a5bc-1f7b06ece7f6" name="testing2@west.ora.com">
   <a n="uid">testing2</a>
   <a n="mail">testing2@west.ora.com</a>
   <a n="zimbraMailStatus">enabled</a>
   <a n="cn">testing2</a>
   <a n="description">Testing DL for SOAP</a>
   <a n="zimbraId">b5d362c5-ef95-4fce-a5bc-1f7b06ece7f6</a>
   <a n="objectClass">zimbraDistributionList</a>
   <a n="objectClass">zimbraMailRecipient</a>
   <a n="displayName">testing2</a>
   <a n="zimbraMailAlias">testing2@west.ora.com</a>
 </dl>
 <dl id="45c9cd14-811f-426b-888f-42ec05f3d7cc" name="testing3@west.ora.com">
   <a n="uid">testing3</a>
   <a n="mail">testing3@west.ora.com</a>
   <a n="zimbraMailStatus">enabled</a>
   <a n="cn">testing3</a>
   <a n="description">for testing Zimbra SOAP services</a>
   <a n="zimbraId">45c9cd14-811f-426b-888f-42ec05f3d7cc</a>
   <a n="objectClass">zimbraDistributionList</a>
   <a n="objectClass">zimbraMailRecipient</a>
   <a n="displayName">testing3</a>
   <a n="zimbraMailAlias">testing3@west.ora.com</a>
 </dl>
 <dl id="ddcec243-29fd-4aea-b443-912c69b30544" name="testing@west.ora.com">
   <a n="uid">testing</a>
   <a n="mail">testing@west.ora.com</a>
   <a n="zimbraMailStatus">enabled</a>
   <a n="cn">Testing</a>
   <a n="description">Testing DL via SOAP</a>
   <a n="zimbraId">ddcec243-29fd-4aea-b443-912c69b30544</a>
   <a n="objectClass">zimbraDistributionList</a>
   <a n="objectClass">zimbraMailRecipient</a>
   <a n="displayName">Testing</a>
   <a n="zimbraMailAlias">testing@west.ora.com</a>
 </dl>
</GetAllDistributionListsResponse>
</soap:Body>
</soap:Envelope>

Now lets examine parsing this document from disk and examining some of its data. Here is a code snippit to create a DOM object, which we will use later with a DOMCategory.

def reader = new FileReader(new File("/zimbra.xml"))
def doc = DOMBuilder.parse(reader)
def zimbradom = doc.documentElement

Now that we have a dom we can bust out the DOMCategory so that parsing is a snap!

use(groovy.xml.dom.DOMCategory)
{
    soapdom.'soap:Body'[0].'GetAllDistributionListsResponse'[0].'dl'.each { node ->
        println "I am ${node.'@name'}"
    }
}

A simple example but there is a lot to explain here. First you can see that you use indexes to select a given node. In this case our XML document has only one 'soap:Body' node, and only one 'GetAllDistributionListsResponse' node. So we could acutally omit the [0] indexes:

use(groovy.xml.dom.DOMCategory)
{
    soapdom.'soap:Body'.'GetAllDistributionListsResponse'.'dl'.each { node ->
        println "I am ${node.'@name'}"
    }
}

Notice how we select an attribute value on a given element. Simply prefix a '@' symbol before the name of the attribute. See also that the full qualified names are being used to select some elements. Since the document names the element 'soap:Body' it can be selected with that exact name. While the elements that fall in the 'urn:zimbra' and 'urn:zimbraAdmin' namespaces are not prefixed and therefore we do not use a prefix to select said elements (as seen in selecting 'GetAllDistributionListsResponse' and 'dl'). Keep this idea in mind when selecting qualified attributes too!

Samba + Groovy

If you have an application where you need to connect with a Samba server I suggest you use JCIFS. This is a nice library for Java that allows file interaction on a remote machine via Samba. The nice thing about this library is that it uses classes that function just like the file classes you normally use in Java. Here is a nice little groovy script JCIFS:

smbAuth = new NtlmPasswordAuthentication("bob.com", "joe", "smoe")

fullPath = "smb://bob.com/media$/blah.txt"

smbFile = new SmbFile(fullPath, smbAuth)

if(smbFile.exists()) {
    smbDate = new Date(smbFile.getLastModified())
    println "Date on SMB file: ${smbDate}"
}

The above example connects to the samba machine, gets the file we want, and then gets and prints the modified date on that file. You can use this library to write quick scripts to sync files from a non samba machine to another machine (Windows?).

Go Check Out this Loop Tutorial

In combing aboutGroovy I found this nice loop tutorial. I recommend you take a look.

I'm gonna write about Groovy!

Groovy is my choice for hacking something together quick. It has a nice little syntax that help you succinctly express what you want. No semi-colons and type definitions, no problem! Being able to leverage the Java APIs (the best around) with no hassle what-so-ever, pricless! I am writing articles here in hopes that others will pick up and use this fun little language. If nothing else it is a great tool to add to your arsenal.

I'll make sure that I add new things here often. I encourage readers to ask questions, hoping that I can answer them. This could lead me to understand better how groovy could fit into others personal worlds.