Workflow Rules Extender

Common Knowledge now includes a powerful Workflow Rules Extender. This extender allows business rules designers to architect solutions from powerful combinations of both declarative and time and sequence dependant rules. The Workflow Rules Extender provides a graphical editor for defining process flows which can incorporate other rules representations as well as external actions.

Traditionally, rules management systems have focused on declarative representations of business rules, using formats such as decision tables, decision trees and production rules (rete-rules). Unlike the traditional approach using a procedural language representation, a declarative approach allows business rules to be represented in a more understandable and maintainable format. Whilst the best systems will always represent as many business rules as possible in a declarative format, declarative rule formats have a number of limitations relating to the representation of the timing, sequencing and rule inter-dependencies aspects of business rule solutions. These limitations can be overcome by providing for the concept of a "flow" through the system, and defining how rules and actions fit into this flow. This "flow" is often termed "workflow" or "rules-flow".

Considerations of flow within business rules are now being recognised by various authors, commentators, methodologists and product vendors in the field of business rules systems. The responses to this are, however, somewhat varied. Some authors will recommend including flow directly into the definition of the business rules whilst others advocate the restriction of rules representations to declarative formats only. Likewise, some business rules management systems will include facilities for defining basic rule-flows, whilst other vendors will recommend that this be co-ordinated by a dedicated workflow management system. There will be compromises with whichever approach is taken so it is important to make careful consideration of the needs of your particular problem when deciding which approach to adopt.

To understand these issues more fully, it is worth having a quick look at current workflow management systems. The term "workflow" can be easily confused when discussing information systems. This confusion stems from the wide variety of workflow-related terminology and concepts used by vendors, consultants and industry analysts. This in turn, is a consequence of the relative immaturity of the technology, the lack of standardisation and the variety of ways in which a business process can be described. This paper will not attempt to clarify all current workflow terms, rather, we will borrow enough terms as is necessary to explain how a business rules system can be made to satisfy the core workflow requirements of a typical information system.

Let us consider the following definitions:

• Workflow: A Workflow is very general concept describing how to model a process.
• Workflow Management System: A Workflow Management System (WFMS) is a software component that takes as input a formal description of business processes and maintains the state of the processes' executions, thereby delegating activities amongst people and applications.

The first of these definitions is quite clearly a very general description of what workflow can be. This is however a useful definition for us to use as it encompasses most of the explanations of workflow that you are likely to hear from industry commentators. With this definition, we can define workflow models for problems as low-level as the definition of a multi-step mathematical function, or as high-level as an enterprise-wide system for processing customer enquiries. Much of the industry commentary tends to centre around the higher-level enterprise processes, often referring to "Business Process Management". Workflow and Business Process Management tend to have overlapping meanings. Workflow is the preferred term used by technical software developers when denoting a series of related interactions between people and a computer system. Business Process Management has a more broad scope, often covering non-technical issues like analysis organizational impact, from the viewpoint of a manager.

Usages of WFMS's can generally be classified as one of the following three types:

• Enterprise Application Integration (EAI) - A large enterprise will commonly possess a number of disparate applications, each dedicated to a separate functional area. The enterprise may, however, want to combine the functionality of these dedicated applications into a larger organisational business process. This requirement is the purpose of many WFMS's that focus heavily on these integration aspects.
• Co-ordinating people-related tasks - Some WFMSs accompany the process definition tools with easy creation of simple client forms. This approach can deliver high value where the business process involves a lot of people related tasks.
• Embedded workflow engine - With this approach, the workflow engine is embedded within another application. The WFMS is not directly visible to the end-user. The main purpose of this approach is to enable better maintainability and reuse within applications that employ complex workflow-related logic.

It is important to recognise that the Common Knowledge Workflow Rules Extender is not intended to act as an enterprise workflow management system. Rather, it is designed to fulfill the role of an embedded workflow and ruleflow engine within a host system that has a complex set of business rules requirements. Common Knowledge incorporates workflow into rule definitions in order to better represent rules that are utilised by a business during its operations. A dedicated WFMS is generally the solution of choice when an organisation needs off-the-shelf workflow capabilities, including: administration and monitoring of the workflow; pre-built forms for accessing the workflow; and plug-and-play integration with a large array of other software products. Often, however, an organisation's requirements are not centered around these facilities but are focused on the ability to automate a complex business process that is governed by many and varied constraints. Common Knowledge excels at representing and automating this category of requirements.

The Common Knowledge Workflow Rules Extender provides a flexible and feature-rich tool for defining a large variety of complex process flows. In addition to this, the Workflow Rules Extender can be combined with any other Common Knowledge Rules Extender (rules representation) to produce powerful hybrid solutions. For example, a set of Workflow rules could be defined to model a business process that incoporates a Decision Tree for deciding the direction of the process flow at a decision point in the flow. However, the tool’s capabilities also go beyond the rich expressive-power available in the process definition. Flexible integration with other systems can be achieved by combining Workflow with Common Knowledge Channels to enable bidirectional communication with external systems and parties. A range of Channel types are supported by Common Knowledge (examples include SMTP-POP3 E-Mail, Socket, and Microsoft Message Queue).

The Common Knowledge Workflow Rules Extender also provides a feature-rich graphical environment for creating workflow process definitions, including a large palette of tools that can be readily assembled into models that cover a wide range of process types. These processes may range from very low-level processes to very high-level processes. Four useful categorisations of process types are shown below with a sample of the Workflow rules created to illustrate each.

Flowchart: A process-flow model that emphasises the decision-making paths that guide someone through a particular process.

Workflow: A set of activities and events that occur during the execution of a business process.

Statemap: A model describing a system that exist in only one particular state at any given time, and moves from one state to another in response to certain external events.

Ruleflow: Used to define control over the sequence of rule execution and chaining.

The same Workflow Rules Extender can be used to create each of the above types of Workflow rules. The Workflow Rules Extender provides tools to model workflows using a variety of control-flow patterns. By adopting this control-flow perspective on workflow, Common Knowledge provides a base set of tools that can be used to build powerful combinations of complex flows.

Another point worth noting is that workflow can provide an intuitive alternative to using procedural scripting in your business rules. Business rule designers sometimes encounter requirements that are difficult to represent using declarative rule representations. Often these problems are related to the control of execution logic and can thus be solved by using procedural scripting languages. The downside to this approach is that these business rules are now represented in a format that is not intuitive to business-oriented users of the rules system. In this situation workflow can represent an effective alternative. The business rules can be incorporated into a workflow process definition that is graphical and, therefore, more intuitive to the business-minded users of the rules. The rules will have greater visibility to a wider range of people and will become more maintainable and understandable as a result.