Tech 18. May. 2006

BPEL vs. XForms

It took some weeks until I finally recieved the thesis of S. Perkles about Server-side XForms processing. Well, it deals not only about XForms but about building a XForm based frontend for BPEL processes. So I realized that “a Web service’s WSDL document provides all the information needed for creating an XForms based front end to the BPEL process” (Ch. 5.2.2). That’s right but was a new perspective for me.

Within the instance data of the XForm all data elements are included - and structured what is the idea of XForms. So after the validation the instance data could be mapped to a SOAP call, which finally invokes the BPEL process engine. All we need is a connector between the XForms processor and the BPEL engine, which maps the instance data of the XForm to SOAP.

But Perkles goes one step further. Since the WSDL document includes all definitions of the interaction and also references XML shemas for details and type definitions, all XForm-relevant information is actually given here. In consequence it is possible to generate the XForm or even to build a generic XForm, which represents the GUI part of any WSDL document. - A quite impressive idea. Actually I thought something more between the WSDL and the user frontend would be needed.

How that could be done is explained in the thesis. And because it sounds like theory I like to mention the sixth chapter, which presents a case study of an implementation using BPWW4J from IBM. I am curious if I am able to go through this.

Reference: Server-side XForms Processing - A Browser-independent Implemantation of the Next Generation Web Forms by Siegfried Perkles, 2003, TU Vienna

Another article: Send Part of an XForms Instance to a Web Service by developerWorks.

It took some weeks until I finally recieved the thesis of S. Perkles about Server-side XForms processing. Well, it deals not only about XForms but about building a XForm based frontend for BPEL processes. So I realized that “a Web service’s WSDL document provides all the information needed for creating an XForms based front end to the BPEL process” (Ch. 5.2.2). That’s right but was a new perspective for me.

Within the instance data of the XForm all data elements are included - and structured what is the idea of XForms. So after the validation the instance data could be mapped to a SOAP call, which finally invokes the BPEL process engine. All we need is a connector between the XForms processor and the BPEL engine, which maps the instance data of the XForm to SOAP.

But Perkles goes one step further. Since the WSDL document includes all definitions of the interaction and also references XML shemas for details and type definitions, all XForm-relevant information is actually given here. In consequence it is possible to generate the XForm or even to build a generic XForm, which represents the GUI part of any WSDL document. - A quite impressive idea. Actually I thought something more between the WSDL and the user frontend would be needed.

How that could be done is explained in the thesis. And because it sounds like theory I like to mention the sixth chapter, which presents a case study of an implementation using BPWW4J from IBM. I am curious if I am able to go through this.

Reference: Server-side XForms Processing - A Browser-independent Implemantation of the Next Generation Web Forms by Siegfried Perkles, 2003, TU Vienna

Another article: Send Part of an XForms Instance to a Web Service by developerWorks.