BEA WebLogic Process Integrator Overview

 

BEA WebLogic Process Integrator is a workflow management system that you use to automate business processes. A business process is a series of interconnected business activities that produce some desired result. A graphical representation of a business process is a workflow. You define and monitor workflows using the BEA WebLogic Process Integrator Studio, a BEA WebLogic Process Integrator client application.

The following sections provide an overview of workflow concepts and BEA WebLogic Process Integrator components:

• Business Processes and Workflows

• Workflow Automation and Management

• Business Organizations and Workflows

• Workflow Design and Integration

• BEA WebLogic Process Integrator Components

• Defining a Workflow

 

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Business Processes and Workflows

In order for a business organization to be effective, numerous discrete business activities must be performed in a sequence that produces the desired result. Business processes provide a way to structure and connect those business activities to achieve the desired result.

For example, in a Web-based ordering system, business activities must work in sequence so that orders are expedited and products are shipped in a timely manner. A business process provides the necessary structure to those business activities: an order is submitted, product availability is checked, customer credit is verified, the order is confirmed, and so on, until the product is shipped.

A business process, however, can be broken down into some basic elements, and the interaction between those elements can be represented graphically. In a typical business process, the basic elements are as follows:

• Start — trigger the start of a business process, and may include externally initiated events, such as order submissions.

• Tasks — perform some business activity, such as checking product availability.

• Decisions — define a business rule that determines the flow of the business process, such as deciding whether a customer's credit is satisfactory.

• End — terminate the process.

We can represent the basic elements of a business process graphically using a workflow diagram such as the one shown in the following figure.

Figure 1-1 Workflow Diagram

 

In this workflow diagram, a start event, such as submitting an order, starts the business process. The order flows from task to task until it encounters a decision, which might cause the flow to change direction. Eventually, the flow reaches an end event, completing the process.

Workflow diagrams such as this one provide a graphical syntax that you can use to model business processes, and to describe how numerous discrete business activities should be sequenced to produce the desired result.

 

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Workflow Automation and Management

In an e-business world, businesses must perform effectively at a rapid pace. To achieve this level of performance, many companies automate their business processes. For these companies, software performs most of the work in a business process.

An automated business process does not, however, entirely replace people with computers. People might still be involved in an automated process, either by making discretionary decisions or by handling exceptions or problems as they arise. Perhaps more importantly, people enable automated business processes by defining, implementing, and managing them. This raises human involvement in business processes to a higher level, enabling people to focus on design and optimization, leaving the execution of routine tasks to computers.

To automate their business processes, organizations use a workflow management system: a system that defines, manages, and executes business processes using software. The order in which business activities are executed in the process is driven by a computer representation of the process called a workflow. A workflow automates a business process by controlling the sequence of activities in the process, and by invoking the appropriate resources required by the various activities in the process. These resources might be software components that perform a required activity, or they might be people who respond to messages generated by the business process.

To achieve this level of workflow automation, a workflow management system provides support in three broad areas:

• Workflow definition and execution—capturing the definition of the workflow, managing the execution of workflow processes in an operational environment, and sequencing the various activities to be performed.

• Data administration—managing the people involved in a workflow, rerouting tasks when needed, and maintaining business workflow calendars that govern the times at which workflows start and end.

• Workflow monitoring—tracking the status of workflow processes, and dynamically configuring the workflow run-time system.

BEA WebLogic Process Integrator supports all three areas of workflow management. BEA WebLogic Process Integrator supports the execution of workflows using its run-time process engine, and the definition and monitoring of workflows with the BEA WebLogic Process Integrator Studio client application.

 

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Business Organizations and Workflows

Businesses typically structure themselves hierarchically, starting with organizations. Each organization can represent a business function, such as accounting, human resources, or information technology, and might operate independently with separate management authority. Within each organization, a set of roles is defined. For example, in an information technology organization, the roles of manager, analyst, and programmer might be defined. For each role, specific individuals are assigned to perform the tasks within the role.

The following figure shows this kind of hierarchical business model.

Figure 1-2 Hierarchical Business Organization

 

BEA WebLogic Process Integrator workflows are organized around this kind of business model, with organizations defined first, followed by roles for each organization, and users for each role.

Organizations, roles, and users can be defined as follows:

• Organization—an entire company; a division, region or location within a company; a geograhical location; or any other distinction that is relevant to the particular business of a company. Using BEA WebLogic Process Integrator, one or more workflows can be defined for an organization.

• Role—a common area of responsibility, ability, or authorization level that is shared by a group of individuals who belong to a particular organization.

• User—an individual assigned to a role who has the necessary permission to perform a particular task in the workflow, such as responding to messages generated by a workflow.

 

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Workflow Design and Integration

Theories of system design suggest that, ideally, systems should be designed using a top-down approach. In reality, systems are designed from both the top down and the bottom up. Both approaches are also used for the design of automated workflows, as the following figure shows.

Figure 1-3 Designing Workflows

 

In this design process, business analysts perform three steps:

1. Define the main process flow.

2. Identify the components required by the workflow.

3. Integrate individual components into the overall design to produce the workflow template.

The template represents the flow of the business process with all of the necessary activities linked in the proper sequence. This workflow representation of the business process is not, however, fully automated at this point.

As we mention in Workflow Automation and Management automated workflows invoke software components to perform the activities required by a business process, such as checking the account balance of a particular customer. When invoking a software component, the workflow can also pass some information to the component to identify the customer, such as an account number. The software component performs some processing to retrieve the account balance, and then returns that information to the workflow.

The software components that the workflow invokes can be built specifically for the workflow being designed, or they can be existing applications invoked by the workflow. These software components are typically Enterprise JavaBeans (EJBs), Java classes in Java applications, or application executables. To make the workflow template fully automated, the template must be integrated with these software components, as the following figure shows.

Figure 1-4 Integrating a Workflow with Business Operations

 

In BEA WebLogic Process Integrator, the functions performed by EJBs and Java classes, and called by workflows, are called business operations. The information that is passed between workflows and software components are stored in entities called variables. You use the BEA WebLogic Process Integrator Studio to design workflow templates and integrate them with software applications by specifying the business operations invoked by a workflow, and the variables used by a workflow to store information.

 

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BEA WebLogic Process Integrator Components

BEA WebLogic Process Integrator is a Java 2 Enterprise Edition (J2EE) implementation of a workflow management system. BEA WebLogic Process Integrator consists of three components, as shown in the following figure.

Figure 1-5 BEA WebLogic Process Integrator Components

 
 

The central component is the run-time process engine which implements the functionality of BEA WebLogic Process Integrator through a collection of EJBs. The BEA WebLogic Process Integrator Studio and the Worklist are client applications that access the services of the process engine. Each of these components is described more fully in the following sections.

Run-Time Process Engine

The central component of BEA WebLogic Process Integrator is the run-time process engine. The process engine is built on the WebLogic Server infrastructure, so installing WebLogic Server is a prerequisite for using BEA WebLogic Process Integrator. The process engine also requires a JDBC database to store persistent data, such as workflow templates.

The process engine is a collection of EJBs that provide the following services:

• Creation and maintenance of workflow templates

• Startup and termination of running workflows

• Run-time control and management of workflow instances as they progress from task to task

• Monitoring of the status and performance of workflows

Studio Client Application

The BEA WebLogic Process Integrator Studio is a client application with a graphical user interface that business analysts, system administrators, and others can use to perform the following tasks:

• Define workflow templates

• Administer data by:

  • Adding, updating, and removing organizations, roles, and users

  • Assigning users to and removing them from roles

  • Configuring levels of permission for users

  • Rerouting tasks from one user to another for a specified period of time

  • Creating business calendars that are used to control the execution of workflows

• Monitor workflows by:

  • Displaying the status of running workflows

  • Modifying the tasks associated with running workflows, such as by reassigning tasks or by forcing work to be redone

  • Displaying the workload status of the system in graphical form

  • Viewing historical data for workflows to identify bottlenecks and inefficiencies

  • Viewing user or role worklists to maintain workflows dynamically

Worklist Client Application

Automated workflows sometimes need input from people. This input might include making discretionary decisions (for example, about credit information), handling exceptions, or troubleshooting problems in the workflow. The Worklist application is a client program that enables people to interact with a running workflow. That interaction is typically performed through a graphical user interface. The interface lists tasks for specific users or roles. Users or roles interact with the workflow by performing the tasks assigned to them.

System Architecture

The following figure shows the overall architecture of BEA WebLogic Process Integrator.

Figure 1-6 BEA WebLogic Process Integrator System Architecture

 

In addition to the process engine and the Studio and Worklist clients, the system architecture includes the following components:

• Template store — holds workflow templates created using the Studio. The template store is implemented through a JDBC database, such as Oracle or SQL Server.

• Instance store —holds running instances of workflows. When started, a workflow is converted to a workflow instance. For any workflow, multiple instances can be running at the same time. System administrators can monitor workflow instances using the Studio. The instance store is implemented through a JDBC database, such as Oracle or SQL Server.

• Plug-in framework — enables third-party developers to extend the functionality provided by BEA WebLogic Process Integrator. The Framework also enables IT departments to seamlessly integrate their systems and applications with BEA WebLogic Process Integrator, thereby simplifying the workflow definition process. Plug-ins are Java classes that are loaded at run time, and that can modify the definition and run-time behavior of selected workflow components.

During run time, the process engine can interact with other applications by performing the following tasks:

• Asynchronously sending or receiving application events in the form of XML documents or JMS messages

• Invoking EJB components and Java classes through an RMI call

• Sending e-mail messages to users of the BEA WebLogic Process Integrator system or outside parties using the SMTP protocol

The process engine also provides a public API that enables external applications to access process engine services.

 

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Defining a Workflow

The BEA WebLogic Process Integrator workflow model is organized hierarchically, as the following figure shows.

Figure 1-7 BEA WebLogic Process Integrator Workflow Model

 
 

In this scheme, organizations are at the top. Roles and workflow templates are attached to an organization, and workflow template definitions are attached to workflow templates. Users belong to an organization, and may also be associated with roles.

To define a workflow according to this model, you perform the following steps using the BEA WebLogic Process Integrator Studio:

1. Specify an organization and its roles, and the users that belong to them.

2. Create a workflow template for the organization you specified.

   A workflow template is a folder that represents a workflow, and is attached to an organization. Give the folder a meaningful workflow name, such as Order Processing or Billing.

3. Create one or more workflow template definitions within the workflow template folder.

   A workflow template definition is a version of the workflow template. You distinguish between workflow template definitions by their effective and expiration dates. For example, you can have one workflow template definition that is valid from January to June, and a second one that is valid from July to December. At run time, the process engine starts an instance of the workflow template definition by selecting the most effective definition.

   Each workflow template definition contains workflow components. These components include the graphical representation of the workflow (called nodes), and the actions, variables, and exceptions handlers that are part of the workflow.

Workflow Components

You create a workflow template definition using four types of components: nodes, actions, variables, and exception handlers. This section describes these components.

Nodes

Nodes are geometric shapes that you use to graphically depict a workflow. The Studio provides the following six nodes:

• Start — represents the beginning of a workflow. A workflow can have the following types of start nodes: predefined, timed, manually initiated, event, or plug-in defined.

• Task — represents a unit of work or discrete activity in the workflow. During the execution of a workflow, task nodes progress through four different stages: created, activated, executed, and done. You can specify task actions in each stage. The task actions are executed as each stage occurs.

• Event — represents a wait state that is activated by the receipt of an XML message. Once an event node is activated, any actions defined within the event node are executed, and the process flow proceeds to the next node.

• Join — represents one of two conditions that must be fulfilled before the node that follows the join node is activated. There are two types of joins: AND and OR. In an AND join, the nodes linked by the join node must be satisfied before the node that follows the join node is activated. In an OR join, only one of the nodes linked by the join node must be satisfied before the node that follows the join node is activated.

• Decision — represents a condition (specified in the node) that must be evaluated. The result of the evaluation determines the path the workflow follows. Conditions can evaluate to either true or false. If a condition is verified, it is true. If it is not, it is false.

• Done — represents the end of a workflow.

Actions

Actions are units of work that you can specify in any node except a join node. An action can be as simple as assigning a task to a user, or as complicated as sending and receiving XML messages. There are several types of actions:

• Task actions — used to specify and control tasks. For example, you can specify task actions such as execute a task, mark a task as done, or assign a task to a user or a role.

• Workflow actions — used to manage an entire workflow, such as stopping the current workflow or starting a subworkflow.

• Integration actions — used to integrate the workflow with external software components or applications. This can be done by, for example, calling an executable program or sending an XML message to another application.

• Exception handling actions — used to invoke and exit an exception handler, and to make an exception handler the active one for a workflow.

• Miscellaneous actions — used to perform additional actions, such as sending e-mail, making an audit entry, or canceling a workflow event.

• Custom actions (plug-ins) — actions that you define and integrate into the workflow.

Variables

Variables hold run-time values and data obtained usually from outside sources, such as external applications.

Variables can hold values that are returned by business operations, that are extracted from XML documents, or that are set explicitly by workflow actions. Variables can also be used by the workflow for several other purposes, such as to evaluate a condition in a decision node, or to store the result of a response from the Worklist client application.

BEA WebLogic Process Integrator supports the following types of variables: Boolean, date, double, entity EJB, integer, Java object, session EJB, string, and XML.

Exception Handlers

Exception handlers are used to generate, trap, and respond to exception conditions that are generated internally or externally. Exceptions can be abnormal conditions that you define in the workflow and that you want to trap, or they can be server exceptions that you trap and respond to accordingly. Workflows can contain exception handlers that are provided by the system or that are defined by you.