Month: April 2012

During my years on the Mule Community forum I’ve noticed that there are some problem areas that are more common than others. One recurring question, that I thought I should address here, is how to preserve message order in JMS.

The first solution coming to mind is to use exclusive consumer, but I’ve come to realise that there are some disadvantages with exclusive consumer such as having active consumers doing nothing (I don’t like the idea of having workers ready to dig in but they are not allowed to). Another thing is that, with exclusive consumer, a message might block another message even though they really don’t have anything to do with each other. For example, let’s say we’re dealing with car orders, then you probably don’t want a order for a Volvo, that doesn’t go through, to block a order for a Saab (I’m Swedish).

For the past few months we’ve been busy working hard on the next version of Mule, release 3.3.  This release candidate includes all the new features and improvements from Milestone  1 and Milestone 2, as well as those that we have introduced since.

As you’ll see, we didn’t slow down as we neared feature-complete, but continued to make high-impact improvements.  In a nutshell, this release includes:

• Mule Expression Language – a concise way to work with any payload, message headers and attachments.
• HTTP Response builder – a new element that makes it easy to work with HTTP responses for REST or general resource calls.
• HTTP Proxy – a new pattern that allows you to front any HTTP resource with routing, filtering and caching.
• Transformations – improved implicit transformation capabilities, enforcement and lookups, which make it easier to work with different data types and content types.
• Syntax Sugar – a couple of new elements have been added to make it easier to work with variables and the payload and to make flows more concise and easier to read.

Flow Controls, as the name suggests, control how messages are sent and received within a Mule flow. In the following examples, we’ll learn about the various Flow Controls that Mule offers. First up: Choice Router.

Choice Router allows us to route a request to a specific path based on an expression. Mule provides implementations of all the common enterprise integration patterns from this recommended book. The Choice router enables content-based routing, which is a common way to introduce routing logic based on content of the current message.