An interesting question popped up on my Oracle Middleware and Cloud Computing book site which I like to answer here for the benefits of all the others puzzling at similar integration questions. In the context of using JMS as an integration technology I’d like to summarize the usage scenarios for Oracle WebLogic JMS Store-and-Forward and JMS-bridges (both are included in WebLogic server).
Hi Frank – [ ...] We have a requirement to build 2-way asynchronous integration between an application running on WLS in AWS and a legacy J2EE app running on IBM WebSphere in our Data Centre. From your excepts my understanding is that SQS is intended for use only between AWS apps – is this correct ? I think we need to be looking at a full JMS solution for our integration – perhaps using WLS JMS Store-And-Forward – Thanks, Peter D
Based on your comment I cannot go into great detail or even provide a solid architecture that anwsers you question (one that will save you from more reading) but here are some important points to consider:
- Amazon’s SQS is not restricted to be only used from AWS instances. SQS is purely based on web services (or language bindings that encapsulate those WS calls) so you can use it from any computer. E.g. you can read or write to SQS queues from remote.
- WLS Store-and-Forward (SAF) can only couple WLS instances of the same version and does not bridge to other JMS providers. You cannot use SAF to transfer from WLS JMS to IBM MQSeries (or whatever Websphere might use). JMS is a pretty bad integration technology which requires to have the right messaging classes in your classpath. E.g. when writing messages from Websphere to a WebLogic JMS queue you are required to have the WLS JMS classes in Websphere classpath.
- You can use the WebLogic’s JMS bridge to solve the somehow messy classpath issues. WLS JMS bridge has to be deployed as JCA adapter (still the jar file from the other provider is required but it is not used in custom code). The bridge will automatically forward from e.g. WLS JMS to MQSeries and even supports transcations. However there is no support to bridge between WLS JMS and AWS SQS.
- Unlike let’s say Oracle Service Bus, if you are looking at Apache Camel there is support to convert incoming JMS messages to outgoing SQS. Note to Oracle’s product manager of OSB: we would appreciate to have SQS as a supported transport protocol or possibly as an SOA Suite JCA adapter. Thanks for considering it