Welcome!

XML Authors: Elizabeth White, Anne Buff, Liz McMillan, Carmen Gonzalez, Paige Leidig

Related Topics: SOA & WOA, XML

SOA & WOA: Article

BPEL Processes and Human Workflow

Using BPEL in business processes that require human interaction

Business Process Execution Language (BPEL), one of the key technologies for Service Oriented Architecture (SOA), has become the accepted mechanism for defining and executing business processes in a common vendor-neutral way. Companies ranging from Oracle, IBM, Microsoft, SAP, and BEA to smaller organizations such as Fuego and Lombardi have committed to BPEL as a building block for SOA. BPEL, which has been designed specifically for defining business processes, supports typical interactions such as synchronous and asynchronous operation invocation, sequential and parallel flows, message correlations, fault and compensation handlers and activities triggered by events. Business processes often require human interactions as well.

Since the BPEL specification doesn't address them, you might think BPEL isn't suitable for business processes that involve people. But that's not the case. In this article, we'll look at different choices for human workflow support - including future possible extensions to the BPEL specification and current vendor solutions - and analyze their relevance in practical scenarios. We'll also discuss real-world scenarios in which BPEL and human workflow services are used and show how one company is using BPEL to integrate people with processes - and the benefits achieved through this approach.

User Interaction in Business Processes
BPEL business processes are defined as collections of activities that invoke services. BPEL doesn't make a distinction between services provided by applications and other interactions, such as human interactions. And that's important since real-world business processes often integrate not only systems and services but also users. User interactions in business processes can be simple, such as approving certain tasks or decisions, or complex, such as delegation, renewal, escalation, nomination, or chained execution.

Task approval is the simplest and probably the most common user interaction. In a business process for opening a new account, a user interaction might be required to decide whether the user is allowed to open the account. If the situation is more complex, a business process might require several users to make approvals, either in sequence or in parallel. In sequential scenarios, the next user often wants to see the decision made by the previous user. Sometimes, particularly in parallel user interactions, users aren't allowed to see the other users' decisions. This improves the decision potential. Sometimes one user doesn't even know which other users are involved - or whether any other users are involved at all.

A common scenario for involving more than one user is workflow with escalation. Escalation is typically used in situations where an activity doesn't fulfill a time constraint. In such a case, a notification is sent to one or more users. Escalations can be chained, going first to the first-line employees and advancing to senior staff if the activity isn't fulfilled.

Sometimes it's difficult or impossible to define in advance which user should perform an interaction. In this case, a supervisor might manually nominate the task to other employees; the nomination can also be made by a group of users or by a decision-support system.

In other scenarios, a business process may require a single user to perform several steps that can be defined in advance or during the execution of the process instance. Even more complex processes might require that one workflow is continued with another workflow.

User interactions aren't limited to approvals; they can also include data entries or process management issues, such as process initiation, suspension, and exception management. This is particularly true in long-running business processes, where, for example, user exception handling can prevent costly process termination and related compensation for those activities that have already been successfully completed.

As a best practice for human workflows, it's usually not wise to associate human interactions directly with specific users; it's better to connect tasks to roles and then associate those roles with individual users. This gives business processes greater flexibility, letting any user with a certain role interact with the process and enabling changes to users and roles to be made dynamically.

BPEL and User Interaction
So far we've seen that user interaction in business processes can get quite complex. Although BPEL specification 1.1 (and the upcoming BPEL 2.0) doesn't specifically cover user interactions, BPEL is appropriate for human workflows. Several vendors today have created workflow services that leverage the rich BPEL support for asynchronous services. In this fashion, people and manual tasks become just another asynchronous service from the perspective of the orchestrating process and the BPEL processes stay 100% standard.

We now see the next generation of workflow specifications emerging around BPEL with the objective of standardizing the explicit inclusion of human tasks in BPEL processes. This proposal is called BPEL4People and was originally put forth by IBM and SAP in July 2005. Other companies, such as Oracle, have also indicated that they intend to participate in and support this effort.

The most important extensions introduced in BPEL4People are people activities and people links. People activity is a new BPEL activity used to define user interactions; in other words, tasks that a user has to perform. For each people activity, the BPEL server must create work items and distribute them to users eligible to execute them. People activities can have input and output variables and can specify deadlines.

To specify the implementation of people activities, BPEL4People introduced tasks. Tasks specify actions that users must perform. Tasks can have descriptions, priorities, deadlines, and other properties. To represent tasks to users, we need a client application that provides a user interface and interacts with tasks: it can query available tasks, claim and revoke them, and complete or fail them.

To associate people activities and the related tasks with users or groups of users, BPEL4People introduced people links. People links are somewhat similar to partner links; they associate users with one or more people activities. People links are usually associated with generic human roles, such as process initiator, process stakeholders, owners, and administrators.

The actual users who are associated with people activities can be determined at design time, deployment time, or runtime. BPEL4People anticipates the use of directories such as LDAP to select users; however, it doesn't define the query language used to select users. Rather, it foresees the use of LDAP filters, SQL, XQuery, or other methods.

BPEL4People proposes complex extensions to the BPEL specification, however so far it's still quite high level and doesn't yet specify the exact syntax of the new activities mentioned above. Until the specification becomes more concrete, we don't expect vendors to implement the proposed extensions. But while BPEL4People is early in the standardization process, it shows a great deal of promise.

Finally, as it stands today, the BPEL4People proposal raises an important question: Is it necessary to introduce such complex extensions to BPEL to cover user interactions? As described previously, some vendor solutions model user interactions as just another Web Service with well-defined interfaces for both BPEL processes and client applications. This approach doesn't require any changes to BPEL; to become portable, it would only need an industry-wide agreement on the two interfaces. And of course, both interfaces can be specified with WSDL, which gives developers great flexibility and lets them use practically any environment, language, or platform that supports Web Services. An example of such an approach is the Workflow Service in the Oracle BPEL Process Manager, which we'll describe later.

First, we should complete the discussion of standards efforts by pointing out that there are several older workflow specifications, most notably Wf-XML from the Workflow Management Coalition (WfMC). Wf-XML is an XML-based proposal for consistent data transfer between workflow engines. As far as we know, it hasn't been used in any major BPEL engine, probably because WfMC and the Business Process Management Initiative jointly released the XML Process Definition Language. XPDL focuses on the design-time interoperability of different workflow products and is therefore only of very limited relevance to the BPEL community.

Clearly, a single standard approach hasn't yet been adopted for extending BPEL to include human tasks and workflow services. However, this doesn't mean that developers can't use BPEL to develop business processes with user interactions. In the rest of this article, we're pragmatic and describe one approach that works today for integrating user interactions in standard BPEL processes.

Workflow Integration with BPEL
To interleave user interactions with service invocations in BPEL processes we can use a workflow service, which interacts with BPEL using standard WSDL interfaces. This way, the BPEL process can assign user tasks and wait for responses by invoking the workflow service using the same syntax as for any other service. The BPEL process can also perform more complex operations such as updating, completing, renewing, routing, and escalating tasks.

After the BPEL process has assigned tasks to users, users can act on the tasks by using the appropriate applications. The applications communicate with the workflow service by using WSDL interfaces or another API (such as Java) to acquire the list of tasks for selected users, render appropriate user interfaces, and return results to the workflow service, which forwards them to the BPEL process. User applications can also do other tasks such as reassign, escalate, route, suspend, resume, and withdraw. Finally, a workflow service may allow other communication channels, such as e-mail and SMS, as shown in Figure 1.

Oracle BPEL Process Manager uses such an architectural abstraction to integrate standard BPEL functionality with workflow. Loose coupling lets workflow services be deployed on any supported application server. It also allows evolving the workflow service, as specifications such as BPEL4People emerge, without having to change the existing BPEL processes. The workflow service includes a simple yet powerful set of Java APIs and WSDL interfaces for building UI workflow interfaces; these offer maximum interoperability for UI approaches, including JSF, AJAX, .NET, and Adobe Flex.

Case Study
Let's look at a case study that shows how you can incorporate human interactions with BPEL. Consider a business process for opening a new bank account; we'll call this process "New Account." The customer provides the necessary details (such as name, address, social security number, and initial deposit) to open the account. Once the process is initiated, the customer may want to track the status of the request and respond to any additional queries from the bank. This process requires a workflow to enable customer participation and process monitoring so that the customer can track the request status.


More Stories By Matjaz Juric

Dr Matjaz B. Juric is a professor at the University of Maribor. He is the author of Business Process Execution Language for Web Services, 2nd Edition, published by Packt Publishing (www.packtpub.com), and several other books, articles, and conference presentations. He is also the author of courses offered by BPELmentor.com - a training, mentoring, and consulting company (www.BPELmentor.com).

More Stories By Doug H. Todd

Doug Todd is CTO of Enterra Solutions in Yardley, Pa. He has more than 20 years of experience in systems architecture, applications architecture, systems integration, and applications integration with major corporations. Todd is responsible for Enterra’s overall IT strategy and tactical implementation, enterprise information architecture, and technology product offerings.

Comments (4) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Arnaud Blandin 05/12/06 12:42:10 PM EDT

Hi,

Thanks for this great article that summarizes part of the issue of integrating Human Workflow in BPEL processes.
At Intalio, we have decided to implement BPEL4People without extending the BPEL 2.0 spec. Our implementation is based on a 5 year experience of integrating human users within business processes.
The Intalio|Workflow component is based on XForms and a set of processes deployed as BPEL 2.0 code on the Intalio|Server (aka PXE). The nice thing is that the forms representing the tasks are edited graphically through a WYSISWYG editor integrated in Intalio|Designer, an eclipse based application.
It leads me to another comment, having BPEL supporting human interaction is one side of the problem. The other side is focused on the business side of the process design. It is important to have a visual representation of Human interactions within a process. Intalio|Designer has adopted the BPMN specification to describe business processes but BPMN does not yet fully support 'Human task' as a first class citizen.

One last comment is that Intalio|Workflow Community Edition comes for free as well as the entire product ;). Check out our community website to become a member of our community.

SYS-CON Belgium News Desk 04/12/06 03:16:51 PM EDT

Business Process Execution Language (BPEL), one of the key technologies for Service Oriented Architecture (SOA), has become the accepted mechanism for defining and executing business processes in a common vendor-neutral way. Companies ranging from Oracle, IBM, Microsoft, SAP, and BEA to smaller organizations such as Fuego and Lombardi have committed to BPEL as a building block for SOA. BPEL, which has been designed specifically for defining business processes, supports typical interactions such as synchronous and asynchronous operation invocation, sequential and parallel flows, message correlations, fault and compensation handlers and activities triggered by events. Business processes often require human interactions as well.

SYS-CON India News Desk 04/12/06 02:31:28 PM EDT

Business Process Execution Language (BPEL), one of the key technologies for Service Oriented Architecture (SOA), has become the accepted mechanism for defining and executing business processes in a common vendor-neutral way. Companies ranging from Oracle, IBM, Microsoft, SAP, and BEA to smaller organizations such as Fuego and Lombardi have committed to BPEL as a building block for SOA. BPEL, which has been designed specifically for defining business processes, supports typical interactions such as synchronous and asynchronous operation invocation, sequential and parallel flows, message correlations, fault and compensation handlers and activities triggered by events. Business processes often require human interactions as well.

SOA Web Services Journal News Desk 04/12/06 02:20:52 PM EDT

Business Process Execution Language (BPEL), one of the key technologies for Service Oriented Architecture (SOA), has become the accepted mechanism for defining and executing business processes in a common vendor-neutral way. Companies ranging from Oracle, IBM, Microsoft, SAP, and BEA to smaller organizations such as Fuego and Lombardi have committed to BPEL as a building block for SOA. BPEL, which has been designed specifically for defining business processes, supports typical interactions such as synchronous and asynchronous operation invocation, sequential and parallel flows, message correlations, fault and compensation handlers and activities triggered by events. Business processes often require human interactions as well.

@ThingsExpo Stories
SYS-CON Events announced today that TeleStax, the main sponsor of Mobicents, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. TeleStax provides Open Source Communications software and services that facilitate the shift from legacy SS7 based IN networks to IP based LTE and IMS networks hosted on private (on-premise), hybrid or public clouds. TeleStax products include Restcomm, JSLEE, SMSC Gateway, USSD Gateway, SS7 Resource Adaptors, SIP Servlets, Rich Multimedia Services, Presence Services/RCS, Diame...
Samsung VP Jacopo Lenzi, who headed the company's recent SmartThings acquisition under the auspices of Samsung's Open Innovaction Center (OIC), answered a few questions we had about the deal. This interview was in conjunction with our interview with SmartThings CEO Alex Hawkinson. IoT Journal: SmartThings was developed in an open, standards-agnostic platform, and will now be part of Samsung's Open Innovation Center. Can you elaborate on your commitment to keep the platform open? Jacopo Lenzi: Samsung recognizes that true, accelerated innovation cannot be driven from one source, but requires a...
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at Internet of @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, will discuss how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money! Speaker Bio: Esmeralda Swartz, CMO of MetraTech, has spent 16 years as a marketing, product management, and busin...
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, will address the big issues involving these technologies and, more important, the results they will achieve. How important are public, private, and hybrid cloud to the enterprise? How does one define Big Data? And how is the IoT tying all this together?
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core of our infrastructures. At the same time, we have old approaches made new again like micro-services...
SYS-CON Events announces a new pavilion on the Cloud Expo floor where WebRTC converges with the Internet of Things. Pavilion will showcase WebRTC and the Internet of Things. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices--computers, smartphones, tablets, and sensors – connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades.
The only place to be June 9-11 is Cloud Expo & @ThingsExpo 2015 East at the Javits Center in New York City. Join us there as delegates from all over the world come to listen to and engage with speakers & sponsors from the leading Cloud Computing, IoT & Big Data companies. Cloud Expo & @ThingsExpo are the leading events covering the booming market of Cloud Computing, IoT & Big Data for the enterprise. Speakers from all over the world will be hand-picked for their ability to explore the economic strategies that utility/cloud computing provides. Whether public, private, or in a hybrid form, clo...
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridsto...
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
As the Internet of Things unfolds, mobile and wearable devices are blurring the line between physical and digital, integrating ever more closely with our interests, our routines, our daily lives. Contextual computing and smart, sensor-equipped spaces bring the potential to walk through a world that recognizes us and responds accordingly. We become continuous transmitters and receivers of data. In his session at Internet of @ThingsExpo, Andrew Bolwell, Director of Innovation for HP’s Printing and Personal Systems Group, will discuss how key attributes of mobile technology – touch input, senso...
The Internet of Things (IoT) is making everything it touches smarter – smart devices, smart cars and smart cities. And lucky us, we’re just beginning to reap the benefits as we work toward a networked society. However, this technology-driven innovation is impacting more than just individuals. The IoT has an environmental impact as well, which brings us to the theme of this month’s #IoTuesday Twitter chat. The ability to remove inefficiencies through connected objects is driving change throughout every sector, including waste management. BigBelly Solar, located just outside of Boston, is trans...
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, will examine three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics...
Internet of @ThingsExpo Silicon Valley announced on Thursday its first 12 all-star speakers and sessions for its upcoming event, which will take place November 4-6, 2014, at the Santa Clara Convention Center in California. @ThingsExpo, the first and largest IoT event in the world, debuted at the Javits Center in New York City in June 10-12, 2014 with over 6,000 delegates attending the conference. Among the first 12 announced world class speakers, IBM will present two highly popular IoT sessions, which will take place November 4-6, 2014 at the Santa Clara Convention Center in Santa Clara, Calif...
The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at Internet of @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., will show what is needed to leverage the IoT to transform your business. He will discuss opportunities and challenges ahead for the IoT from a market and tec...
From a software development perspective IoT is about programming "things," about connecting them with each other or integrating them with existing applications. In his session at @ThingsExpo, Yakov Fain, co-founder of Farata Systems and SuranceBay, will show you how small IoT-enabled devices from multiple manufacturers can be integrated into the workflow of an enterprise application. This is a practical demo of building a framework and components in HTML/Java/Mobile technologies to serve as a platform that can integrate new devices as they become available on the market.
SYS-CON Events announced today that O'Reilly Media has been named “Media Sponsor” of SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. O'Reilly Media spreads the knowledge of innovators through its books, online services, magazines, and conferences. Since 1978, O'Reilly Media has been a chronicler and catalyst of cutting-edge development, homing in on the technology trends that really matter and spurring their adoption by amplifying "faint signals" from the alpha geeks who are creating the future. An...
The Transparent Cloud-computing Consortium (abbreviation: T-Cloud Consortium) will conduct research activities into changes in the computing model as a result of collaboration between "device" and "cloud" and the creation of new value and markets through organic data processing High speed and high quality networks, and dramatic improvements in computer processing capabilities, have greatly changed the nature of applications and made the storing and processing of data on the network commonplace.
SYS-CON Events announced today that Aria Systems, the recurring revenue expert, has been named "Bronze Sponsor" of SYS-CON's 15th International Cloud Expo®, which will take place on November 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Aria Systems helps leading businesses connect their customers with the products and services they love. Industry leaders like Pitney Bowes, Experian, AAA NCNU, VMware, HootSuite and many others choose Aria to power their recurring revenue business and deliver exceptional experiences to their customers.
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce the value of the network in helping organizations to maximize their company’s cloud experience.
As a disruptive technology, Web Real-Time Communication (WebRTC), which is an emerging standard of web communications, is redefining how brands and consumers communicate in real time. The on-going narrative around WebRTC has largely been around incorporating video, audio and chat functions to apps. In his session at Internet of @ThingsExpo, Alex Gouaillard, Founder and CTO of Temasys Communications, will look at a fourth element – data channels – and talk about its potential to move WebRTC beyond browsers and into the Internet of Things.