This week, MuleSoft released version 3.1 of its enterprise service bus, Mule ESB. Mule 3.0 was released in September with one major focus: "simplify everything...to make Mule 3 more accessible to everyone". Mule 3.1 takes the simplification further by focusing on Mule Cloud Connect, Mule Flow and BPM.
Mule Cloud Connect is the branding for Mule's ability to use publicly available services. Version 3.1 ships with only four connectors to use Twitter, SalesForce and online payment services Authorize.Net and Cybersource. All of the Mule announcements use Twitter as an example, so to change things up below is an example of Authorize.NET processing a credit card payment:
<auth:config merchantLogin="<YOUR MERCHANT LOGIN>" merchantTransactionKey="<YOUR MERCHANT TRANSACTION KEY>" name="auth" testMode="true"/>
<flow name="payment">
<http:inbound-endpoint address="http://localhost:9898/payment" exchange-pattern="request-response"/>
<auth:authorization-and-capture cardNumber="370000000000002" expDate="12/12" amount="400"/>
<expression-transformer>
<return-argument evaluator="bean" expression="responseReasonText"/>
</expression-transformer>
</flow>
Developers can also build their own cloud connectors (instructions, login required) that use their own, custom XML schema for configuration.
Mule Flow, which was introduced in version 3.0, was improved with added support for three higher-level abstractions: "invoke" which calls a service, "poll" which monitors an endpoint and triggers a process when something arrives, and "enricher" which can take the results of a system call and inject them into the payload of the currently running process. In addition, version 3.1 upgrades the underlying version of Apache CXF to 2.3.0 and adds support for Spring Security v3.
Lastly, Mule loosened up its relationship with Business Process Management (BPM). jBPM is "now a component in Mule rather than a transport, this not only enable the use case when we are connecting to an external BPM engine but also enable the use case when using jBPM "inside" Mule to process messages". One practical implication of this change is that the BPM transport that was deprecated as of Mule 3.0.1 has now been removed in 3.1. The new recommended way to interact with BPM is via the "<bpm:process>" message processor.
While Mule code is open source under the CPAL license, extra features like the Mule management console and other features require a commercial license. Other alternatives to Mule include Apache ServiceMix, Apache Synapse and JBoss ESB. With 3.1's Flow capability, Mule also starts to resemble integration solutions like Apache Camel and Spring Integration.