SOA Redefined : Getting Started - XQuery Dev inside OSB Eclipse

We can use XQuery/XSL in OSB to do the message transformation. But XQuery is preferred over the XSL because of the performance advantage. In this post I will show how to develop an xquery using the osb workshop eclipse.

XQuery - Introduction
XQuery is a light weight language which has got an xml like syntax. XQuery has 3 important parts as below

Namespace declaration
Set of function with their implementations
Declaration of variables
Mentioning the function with which the execution begins.

For further understanding of the XQuery you can refer
http://www.w3schools.com/xquery/xquery_intro.asp

Sample XQuery

Listing-1   xquery version "1.0" encoding "Cp1252";
Listing-2   (:: pragma parameter="$anyType1" type="xs:anyType" ::)
Listing-3   (:: pragma type="xs:anyType" ::)
Listing-4   declare namespace xf = "http://tempuri.org/OSB%20Project%203/sample/";
Listing-5   declare namespace ns1 = "http://tempuri.org/OSB%20Project%203/sample/inputaddress";
Listing-6   declare namespace ns2 = "http://tempuri.org/OSB%20Project%203/sample/outputaddress";
Listing-7
Listing-8   declare function xf:sample($requestDoc as element(*))
Listing-9                   as element(*)
Listing-10   {
Listing-11
Listing-12
Listing-13                  {
Listing-14                  $requestDoc/ns1:FirstName/text()
Listing-15                  }
Listing-16
Listing-17
Listing-18                  {
Listing-19                  $requestDoc/ns1:PhoneNumber/text()
Listing-20                  }
Listing-21
Listing-22
Listing-23   };
Listing-24
Listing-25   declare variable $requestDoc as element(*) external;
Listing-26
Listing-27   xf:sample($requestDoc)

Explanation

Listing 1 - declaration of xquery

Listing 2 to 3 - comments

Listing 4 to 6 - Namespace declarations

Listing 8 to 9

This is the code snippet for the function 'sample' which takes 'requestDoc' which is of type element(*), that is the xml. It returns the type element(*) which is also an xml.

Listing 10 - shows the start of the xquery function

Listing 23 - shows the end of the xquery function

Listing 11 to 22 - the body of the function 'sample'

Here we are doing the transformation. What ever we write it in these lines will be the final output of the

xquery tranformation

Listing 14 or 19 - Here we are assigning the data obtained from request xml to the output response xml.

Listing 25 - declaring the request variable 'requestDoc' as 'external' as type 'element(*)'. So when we test this xquery from the OSB flow, we will bind the request xml with 'requestDoc' variable and we can transform the request xml to the response xml.

Listing 27 - This is the last line of the xquery where the execution of the xquery begins. Suppose if we have multiple functions, what ever function is given in the last line of xquery will be the entry point of execution.

Development of XQuery in OSB Workshop - Eclipse
Open the eclipse and create a project . Right click on the project and create a new xquery

Give some name

Now give the request binding variables.
Here I have added only one variable.
Give the 'Parameter Name' as 'requestDoc' and click on 'Add' so that we can add the request binding variable.

Similarly mention the response also

Now we have created the xquery. It will be now opened in the osb eclipse editor. The editor has 3 parts.

Design
Source
Test

We can use 'Design' part if we have the source and destination schemas.

Now click on 'Source' and you can see the xquery source code.

Now modify the xquery as below

xquery version "1.0" encoding "Cp1252";
(:: pragma parameter="$anyType1" type="xs:anyType" ::)
(:: pragma type="xs:anyType" ::)
declare namespace xf = "http://tempuri.org/OSB%20Project%203/sample/";
declare namespace ns1 = "http://tempuri.org/OSB%20Project%203/sample/inputaddress";
declare namespace ns2 = "http://tempuri.org/OSB%20Project%203/sample/outputaddress";
declare function xf:sample($requestDoc as element(*))
    as element(*)
     {


          {
          $requestDoc/ns1:FirstName/text()
          }