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Wednesday September 26 2001 Enabling Web Services with BEA WebLogic Using WebLogic and CapeConnect from CapeClear BEA Systems, Inc., announced full support for Web Services in release 6.1 of their industry leading WebLogic Application Server. Though they had provided this starting from the Beta release of Version 6.1, it was not until the formal release of version 6.1 that developers really started getting serious about taking a look at their Web Services support. In this article, we shall take a look at some of the practical considerations in implementing Web Services in general and then see how we can address those within the BEA WebLogic platform. Of course, during the course of our discussion, we are well aware that it is not feasible for every company to migrate to version 6.1 of the BEA WebLogic Application Server. This is due to the fact that several companies have existing systems on previous versions of WebLogic and they would like to protect their investments in such systems. We shall also discuss options open to a company having version 4.5, 5.1, 6.0 of the WebLogic Application Server in order to enable select aspects of their functionality as Web Services. Web Services Today Web Services as they stand today comprise open Internet standards like WSDL, SOAP, and UDDI. WSDL is used to describe the Web Service, UDDI is used to publish and query Web Services, and finally SOAP is used to invoke the Web Service. This is the common Web Services programming model, as we all know. Web Services provide compelling benefits to organizations that plan to use them. Primary among these include: low-cost of development, open Internet standards, and chiefly the overwhelming support demonstrated by all the system software providers like BEA, IBM, Microsoft, Sun, Oracle, etc. Along with these large organizations, we are seeing a number of smaller organizations announcing toolkits and platforms that ease the development of Web Services. For any organization, finding Web Services platforms and tools is not a problem. Getting them to work together may be though. At the same time, organizations with existing business applications are looking beyond just the simple "describe, list, and invoke programming" approach as propagated by the Web Services programming model. Some of the common concerns that are raised by organizations today are the following:
As noted above, organizations are evaluating these very aspects of Web Services. It would be very difficult to find a Web Services platform today that addresses all of the above. In the remaining part of this article, we shall take a look at how organizations using or planning to use Web Services within the BEA WebLogic platform can address some of the issues. To analyze the options available for implementing Web Services within WebLogic server, we need to classify organizations into two kinds, those that have existing applications on WebLogic Server 4.5/5.1/6.0 and those that are planning to develop afresh on WebLogic 6.1 or planning to migrate to WebLogic 6.1 Customers with Existing Applications on Versions Prior to 6.1 In this case, there is no support for Web Services standards like WSDL, UDDI, or SOAP. For organizations to migrate to version 6.1 of WebLogic is often not practical from a business sense. One of the extreme options that a company can choose is to implement the Web Services standards within their application. But this requires deep technical expertise and extensive testing. On the other hand, there are several Web Services platforms that are available today from vendors that help protect existing investment in EJBs and help expose the functionality in them as Web Services. Let us consider how this can be achieved today using a Web Services enabling platform like CapeConnect for J2EE from CapeClear Software (http://www.capeclear.com/). We shall assume that the application is running on one of the following versions of WebLogic: 4.5, 5.1, or 6.0. CapeConnect is a Web Services platform that allows you to expose your existing Java and EJB components as Web Services, providing full support for WSDL, UDDI, and SOAP. Let us take a look at the following diagram showing how this is possible:
We will start from the extreme right where the current application functionality resides in the WebLogic Application Server. Of course, it is important to note that one does not expose functionality present in the EJBs as it is. Instead, the organization will accordingly decide on aspects of this functionality that need to be exposed. In the diagram we assume that the EJBs represent the functionality that needs to be exposed as Web Services. The steps involved in exposing these EJBs are Web Services are as follows:
So from the above process we find that using a CapeConnect Web Services platform is a convenient way to expose functionality in existing EJBs as Web Services. Exposing Web Services and using them via the generated stubs, however, is more of a Point-to-Point integration scenario. A Point-to-Point integration between two applications means that both applications are aware of each other's details, thereby resulting in tighter integration. This, however, sacrifices key features like being able to adapt to changes in the two applications. As we had highlighted before, though, such a process suffers from inherent drawbacks, some of which are listed below:
Until recently, this strength has been somewhat mitigated by the fact that there were several competing Java commerce platform vendors that did not comply, nor intend to comply, with the J2EE standard, Sun's platform for enterprise computing. In the main, companies have quoted their lack of faith in the technology, though the loss of existing code bases and the work to convert the rest must have been overwhelming. To some extent this was no doubt in part due to the proprietary, counter standards approach to application servers that has been the norm until recently. Customers Migrating to or Using Version 6.1 WebLogic 6.1 enables full support for Web Services standards like WSDL and SOAP. For organizations that are planning to migrate to WebLogic 6.1, they can continue to use a third-party Web Services platform like CapeConnect. In this section, however, we shall take a look at the Web Services support provided by WebLogic 6.1 itself. In summary, WebLogic 6.1 provides the following features as shown below. Note that we relate this to the components that CapeConnect software provides as we saw in the previous section:
From this discussion, it should be clear how the WebLogic 6.1 Web Services solution closely mirrors the approach CapeConnect employs to enable the EJBs in pre-6.1 versions of WebLogic. Apart from an additional way of invoking your Web Services (asynchronous), this simple enabling of Web Services in WebLogic 6.1 still suffers from the same drawbacks that we listed before: lack of business process support, lack of support for XML-standards, etc. BEA WebLogic Integration So, what is BEA trying to do to address these issues, without which acceptance of Web Services into enterprises will remain but a dream? BEA have introduced a new product called BEA WebLogic Integration, which is really an integrated offering of four products in one:
If you look in detail at the B2B Integration part of the BEA WebLogic Integration product, you find that it really takes the simple Web Services that we described in the previous section to a more complex level typically used in a business scenario. It thus meets some of the requirements that we identified in this article. Some of the features that it provides are as follows:
Conclusion From this article, readers should be able to get an understanding of possible approaches available today to help enable Web Services in BEA WebLogic Application Server. We considered not only organizations that will continue to use older versions of WebLogic Application Server in which there is no native Web Services support, but we also saw the simple Web Services support provided by WebLogic version 6.1. The solutions for both these cases, however, fall short of complex business processes that are prevalent in organizations today. It is hoped that platforms like the BEA WebLogic Integration solution will provide a single platform that will help to address issues of multi-party, collaborative processes that will help ease organizations into global electronic business. The author hopes to provoke debate from vendors of Web Services platforms and toolkits regarding their efforts to solve the problems outlined here. Similar articles: |