SDT Core

The SDA project was conceived in 2008 and aims to produce Java libraries that (ultimately) support parsing, validation and transformation of SDA content. The SDT core library supplies classes to parse and execute transformation scripts. It depends on the SDA core library and on Jaxen for XPath support.

What is SDT

SDT is to SDA what XSLT is to XML. In other words, it is a language that allows you to create mapping and transformation recipes to read and write SDA content.

For example, this recipe parses an 'addressbook' in SDA format and produces a new SDA document with the same data in a different format, while using functions to transform the node values:

transform {

    param "filename" { select "'addressbook.sda'" }
    variable "doc" { select "document($filename)" }

    node "contacts" {
        foreach "$doc/addressbook/contact" {
            node "person" { 
                value "upper-case(firstname)"
                node "phones" {
                    value "fn:string-join(phonenumber,',')"
                }
            }
        }
    }
}

As you can see the transform reads like a scripting language if you are already familiar with SDA and XPath. I do not expect you to grasp the SDT syntax at a glance, so please refer to the tutorial and specification for details.

Running the demo

You may read up on SDA before running the SDT demo, but this is not required.

In order to run the demo, get demo.jar, addressbook.sda and addressbook.sdt from the latest release and copy these to a temporary directory where you will run the demo. Assuming the java executable is in your path, run it like this:

java -jar demo.jar addressbook.sdt addressbook.sda

This will transform the data in the file addressbook.sda according to the recipe shown earlier.

addressbook {
    contact "1" {
        firstname "Alice"
        phonenumber "06-11111111"
        phonenumber "06-22222222"
    }
    contact "2" {
        firstname "Bob"
        phonenumber "06-33333333"
        phonenumber "06-44444444"
    }
}

into

output {
    contacts {
        person "ALICE" {
            phones "06-11111111,06-22222222"
        }
        person "BOB" {
            phones "06-33333333,06-44444444"
        }
    }
}

Have a look at the code to see how it was done. I hope this demonstrates the use of SDT for transformation of SDA content. This also concludes my SDA trilogy, but who knows - there may be more to come.