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Vijay Mandava is a Principal Technology Strategist at BEA Systems where he
helps clients build solutions using BEA products. He has been with BEA for over 7 years and has over 12 years experience in building large
scale distributed systems.
WLS 10.3 Tech Preview supports SCA
Posted by vijay.mandava on February 15, 2008 at 9:59 AM | Permalink
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WebLogic 10.3 Tech preview now supports SCA runtime. SCA is a set of specifications and in a nutshell, in my opinion it is the next evolution of building interoperable distributed systems.
The claim to fame for SOAP based web services is that it provided a programming model where clients do not care as to which programming language the service is implemented. The client can be written in any language that has a SOAP binding. The only restriction on the client is that it has to use the SOAP API.
Thus by service enabling your existing business services and modifying your legacy clients to speak SOAP, web services have made enterprise integration easier compared to yester years.
Now SCA takes this interoperability to the next level, where now your clients can stay as is and do not have to use the same transport as the service. All the client knows is that it is a remotable service.
Let us say you have a Java client that was talking to an EJB. Now this EJB has been converted into a web service. In this case, the Java client does not have to change to use SOAP API. Instead it can still use its EJB client code because the web service (which is an SCA component) can be decorated with an EJB binding.
Thus the service can be implemented in one technology such as Spring, POJO, EJB, web service or BPEL and it can be decorated with a different binding(Spring, POJO, EJB, web services etc) to support different clients.
I used the word "decoration" loosely and every component technology (Spring, POJO, EJB etc) that wants to participate in the SCA framework should support SCA metadata. The SCA specification defines language bindings for each of the technologies.
The SCA specification has two main parts - implementation of service components (which can be done in any language) and the assembly model which is the linking of components through wiring (which is done through XML files).
Since WebLogic 10.3 Tech Preview includes an SCA runtime customers now have multiple technology choices to build their business logic -- POJO, EJB, Spring or SCA.
By including the SCA runtime on WLS, customers can take advantage of the RASP functionality provided by WLS for the deployed SCA components. The infrastructural capabilities such as security, transactions, reliable messaging that are to be handled declaratively through policies under the SCA specification can all be provided by WLS.
As I understand it today, SCA only focuses on business services and it will still have to use other presentation frameworks and data access frameworks to provide a total solution. Service Data Objects (SDO) is the preferred mechanism to represent business data.
I would like to hear your thoughts on SCA in general and how you predict its adoption in the near future.
Loosely Coupled Synchronous Design Patterns with Service Bus
Posted by vijay.mandava on September 7, 2007 at 3:46 PM | Permalink
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SOA Journey
Posted by vijay.mandava on June 13, 2007 at 11:29 AM | Permalink
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I have been working with several customers who are either defining their SOA strategy or starting to execute their next leg of the journey. What is interesting is their first leg of the journey. The two most common legs I have seen either starts with mediation or starts with governance.
For the group who is leading with governance, they tend to focus on discovery, quality of service, versioning, dependency analysis, design time and runtime governance, reuse, ROI measurement and runtime usage analysis.
For the group who is leading with mediation, they tend to focus on loose coupling and keeping services completely agnostic of clients. They do not give importance to discovery and tend to implement governance functionality such as versioning, monitoring, runtime usage analysis etc through the mediation layer.
The other legs I have seen customers start their SOA journey is around their data layer, presentation tier and business processes. These projects typically started off as point solutions and then built momentum towards a SOA transformation.
I would like to hear your comments.
ESBs and State Management
Posted by vijay.mandava on June 13, 2007 at 9:30 AM | Permalink
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We have always positioned ALSB as a stateless, low latency ESB that shines in implementing the Validation, Enrichment,Transformation,Routing,Orchestration and Monitoring(VETROM) pattern. The key here is stateless. Often, we get requirements where we need to maintain state. A simple example is to send a message and wait for the response.
To implement that pattern, ALSB provides a simple mechanism where a message based business service implements a request-reply paradigm. The idea is within the business service, you define the request queue and the reply queue and the business service waits until a message arrives in the reply queue.
The only problem with this architecture is if the ALSB server crashes before the reply message arrives, when the server comes back up, there is nobody listening on that reply queue, thus message can get stuck.
To mitigate these stuck messages, a design approach of setting a policy on the reply queue to move the messages to another ExceptionQueue after a configurable time and design a proxy service to consume those messages and take the appropriate action can be utilized.
In one POC, that we recently worked, we had a client sending a non-persistent message to a request queue and was synchronously waiting on a reply queue for 10 seconds. In that scenario, we did not have to worry about stuck messages, since the client would not care about the message after 10 seconds and we implemented the above mentioned request-reply business service approach.
What kind of requirements do you see in your ESB evaluations and are you are taking the route of always positioning a BPM+ESB in the stateful case. One of my customer is looking at ESB+Gigaspaces to handle the stateful ESB requirements.
I would like to hear your thoughts...
Alignment of IT strategy and Business Strategy
Posted by vijay.mandava on February 18, 2007 at 10:00 PM | Permalink
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Every business uses IT today to streamline its processes to provide better operational efficiencies and thus improving their bottom line. So every body sees IT as a cost saver, but how many truly use IT to generate new revenue opportunities. I do not mean creating another channel for customers but a truly new product to your customers that generates top line growth.
How are your company’s IT strategies aligned with your business strategies? Do your business strategies only and always drive your IT strategies or do you routinely create an IT strategy that helps your company redefine their business strategy. Is IT considered a cost center or a strategic division that can also generate top line growth to your company?
From my experience, this answer varies on multiple factors such as culture of the company, the organization structure, the industry vertical, the kind of metrics used to fund new initiatives and the chargeback model used for shared services.
I would like to hear your thoughts around this topic.
WLS-SONIC Integration
Posted by vijay.mandava on February 18, 2007 at 7:47 PM | Permalink
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I recently worked with a customer on a WLS application hosting MDBs listening on Sonic queues. I just assumed that the onMessage call of the message driven bean will be running on a WebLogic thread. But much to my surprise, we found that if the MDB is running in a non transactional manner, the thread executing the onMessage is actually a Sonic thread from the Sonic libraries. I am curious if the behavior is similar with other foreign JMS providers too.
Integration Approaches between BPM and ESB
Posted by vijay.mandava on February 18, 2007 at 7:23 PM | Permalink
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