Integrating heterogeneous subsystems and business units in a corporation is an increasing priority in a globalized economy in which the ability to adapt quickly in response to changes in market conditions determines the success or failure of an enterprise. This case study of an integration project for a large manufacturing/transport account details the use of components of the WebSphere framework.
From an IT perspective, there are many products, technologies, architectural design patterns, and methodologies available to accomplish the goal of adaptability. In this article I will present an application integration scenario, together with a solution based on technologies and products from the IBM WebSphere software platform.
Our customer (undisclosed) is a large manufacturing/transport account structured into several divisions - Holding, Human Resources, Finance, Services - and production departments. The business problem is to integrate these divisions, the services each one provides, and hence the different subsystems on which each division runs its own business.
As an instance of an integration scenario, let's consider the accounting business flow: suppliers, the goods/services acquisition approval cycle, orders, inventory, invoices, and accounting posting are the usual entities and flows involved in this scenario.
Several subsystems are involved in this kind of integration:
- SAP for materials management
- A third-party subsystem running General Ledger
- Several internally developed J2EE modules
- External business partners, such as banks
The requirements for this integration architecture were:
- From a business perspective:
-To increase speed to comply with new government and industry regulations
-To increase efficiency, reducing operational and resource costs
- From an IT perspective:
-Asset reuse through a unified architecture
-The enabling of nondisruptive additions of new applications to processes
-The minimalizing of subsystem dependencies
- From a functional perspective:
-Information integration through formatting rules and content-based routing
-Application integration through standard protocols while trying to maximize information flow reuse
-Business process integration, accomplished by combining several processes to produce a single flexible and extensible workflow Application Integration Infrastructure
The solution discussed in this article was identified by taking into account the following general driving factors:
- Adoption of standard technologies, where applicable
- Adoption of market leader products in their relevant sectors
- Use of a single approach and of a single adapter technology for all application interactions with SAP, independent of the operating environment involved
- Extensive use of the following technologies:
-Message-oriented middleware
-Publish/subscribe
- The definition of application services to access EIS (Enterprise Information System) subsystems, incorporating parts of a service-oriented architecture in the solution, enabling product reuse in different scenarios; a loose connection between service providers and users; location transparency; independence from protocols, formats, and service life cycles
- Interaction based on events, incorporating elements of an event-driven architecture to provide excellent levels of scalability, robustness, and monitoring, along with zero coupling between the parties involved. (One party detects the change of state and publishes it, and all the services that have subscribed to it will receive the notification.)
- Definition of execution flows, obtained through human interaction and the invocation of the available application services; these flows, activated by events, model the company business processes and are easily modifiable in response to the evolution of company organization and strategies.
The IBM products involved in the resulting integration architecture (see Figure 1) and their features are described in the following sections.
WebSphere Application Server Enterprise Edition
WebSphere Application Server is IBM's J2EE-compliant engine; in its Enterprise Edition, infrastructure services and high-value application services have been added to the standard J2EE (EJB, JSP/servlet, JDBC, JCA, JMS) to make it a key platform for executing business processes. These include:
- The Process Choreographer's support for long-running workflows, including micro and macro flows, compensation, restart, and human interaction
- Support for Web services, protocols and standards, and the UDDI registry
- Support for messaging with point-to-point and publish/subscribe paradigms using JMS and MDB
- Strong characteristics of autonomy, performance, security, scalability, and system management
In this solution, WebSphere Application Server Enterprise Edition is the engine for executing the application workflows and for invoking the services on various EISs, e.g., SAP.
WebSphere MQ
WebSphere MQ (WMQ) is the de facto standard for messaging and queuing middleware. Its message delivery service, with its high quality of service, is available on almost every relevant hardware platform, and accessible from a broad range of programming languages, including Java, C, and COBOL; and operating environments, including J2EE and CICS.
In this architecture the application connectivity service is based on WMQ.
WebSphere Business Integration Message Broker
WebSphere Business Integration Message Broker (WBIMB) is a general and extensible integration broker that can manage data streams coming over WMQ or other protocols (e.g., HTTP), and that provides the following services:
- Routing based on content
- Format transformation
- Augmentation of content
- Topic- and content-based publish/subscribe
- Broadcast/multicast
- Support of custom operations through a complete plug-in architecture that can be implemented by the user
WBIMB provides native integration with WMQ. Both of these products allow you to implement high added-value interoperable application buses for all integration at the data level.
In this architecture, WBIMB is used to broker the exchange of data between the various subsystems involved in batch interactions or that request services such as routing and formatting.
WebSphere Business Integration Adapter for mySAP.com
WebSphere Business Integration Adapters (WBI Adapters) are adapters for business applications and third-party middleware (EISs) based on CrossWorlds technology.
The internal architecture and the fundamental standard technologies are common to all adapters in the WBI family. Each adapter contains a specific part relating to the EIS with which it must interface (e.g., mySAP.com); this part is typically based on an API and/or events provided by the EIS producer.
WBI Adapter services are available for the following operating environments:
- WAS
- WBIMB
- WBI InterChange Server
These adapters can take on a passive or active role:
- They can be activated by WAS or WBIMB to execute an operation on the EIS where they operate.
- They can be programmed to detect a modification of the state information managed by EIS, and as a consequence, generate an event.
In this architecture WBI Adapters are used to deal with mySAP.com from WBIMB as well as from WAS (see Figure 2).
Some Integration Scenarios - Process Flow
Example scenario: when an invoice arrives in paper form, an administration employee activates the workflow in order to manage it. The invoice data is entered via a browser, the relevant order is verified, receipt of goods or use of a service is verified, and regulation of payment is managed by a separate workflow. When feedback on payment is received, the invoice is archived and the payment is registered in the accounts subsystem.
Integration between procedures and applications is implemented through execution flows, which are created in a declarative rather than a programming way using the appropriate language (FDL [Flow Definition Language]) and development environment (the WebSphere Studio Integration Edition).
The flows are executed in WAS by the Process Choreographer component. Process flows can be activated by:
- Business events, generated by the SAP adapter when a modification to the state has been detected
- Scheduling, i.e., by defining rules for automatic flow activation in WAS
- Human intervention, e.g., when a new paper invoice is received from a supplier an employee starts a new flow instance to manage it
A business flow is typically composed of one or more tasks, each involving a human interaction or a process activity:
- Human interactions are accomplished through a customizable Web GUI (namely the process Web client) included in WAS; users authorized to operate on these flows are classified into roles and operate on tasks assigned to them executing basic "task claim" and "task completion" operations.
- Process activities are programmed using the services and standards provided by the WAS programming model, such as EJBs and Web services.
Application Connectivity with SAP
Example scenario: verification of the order associated with the invoice received - and verification of the existence of goods in inventory are typical services implemented by SAP, and these can be exposed and used in process flows.
SAP is accessed through services: the services provided by the WBI Adapter are described in WSDL and invoked by WAS via XML/JMS through the WSIF (Web Services Invocation Framework). These services can be used in a process flow executed in WAS.
The services approach is complemented by the adoption of a transport mechanism (WMQ) with assured and guaranteed delivery attributes:
For insert/update/delete interactions (with side effects or business logic invocation) the use of persistent messages guarantees that the operation will be completed even in the case of a node failure, increasing the robustness of the internal infrastructure.
For retrieval interactions or operations, in which double execution after the restoring of a failed node does not cause any undesirable effects, using nonpersistent messages improves performance without compromising robustness.
Event-Driven Interactions
Example scenarios: when a new item arrives it is registered in the inventory; this operation is published as an event, which causes a workflow to start in WAS. In another example, a suspended invoice process can finally be completed.
The events are detected and/or generated by WBI Adapters in the case of SAP, for example, or by third-party applications that are involved in the architecture.
The events are transported by the application connectivity subsystem (WMQ) as messages. With its characteristics of secure and guaranteed delivery and the use of persistent messages, WMQ allows the activity to be completed even in cases of node failure.
The events are addressed to WBIMB, which transmits them, for example, via JMS/MDB to all the subsystems that have subscribed to receive them, carrying out any required processing and transformations to the transported data.
Data Manipulation and Batch Integration
In each phase of its life cycle, data is treated as a business object and not as an opaque byte stream; this is made possible through the virtualization of the base information provided by the WBI Adapters and through WBIMB parsing.
Data transmitted with standard protocols and formats such as JMS and XML can be manipulated in various ways; it is possible to adapt its format to the needs of the receiver or combine it with data retrieved from EISs (e.g., SAP or J2EE modules), and send it to file-based applications.
Example scenario: toward the end of each month it is necessary to activate the payment process of the invoices/bills that are about to expire. At a scheduled time a process flow starts in WAS: a summary of all payments to be made is displayed via a browser; when the user confirms the operation, the data regarding the payment to be carried out is sent to WBIMB, processed, and put into files that are sent to the different banks as appropriate.
This solution can be implemented with the help of products that build on WBIMB's data manipulation capabilities, in this case extended with file tranfer and batch features through Primeur's Spazio File Extender for WBIMB (see Figure 3).
Conclusion
This project, part of which is already in production and part of which is in the process of being completed, has provided several advantages, including increased efficiency, reduced operating costs, and the ability to reuse services and data. In addition, the solution is scalable and has been quick to meet business requirements.
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