We are planning for an upgrade of Mule 4 in a few months. In the meantime we are in the process of putting the development on hold as it’s impossible to locate anyone with Mule 3 certified resources. Do you have any suggestions? The director of the integration program was crying out for assistance. It seems like this is the norm since numerous organizations still rely on the older Mule 3 version.
If you’re an Mule 4 certified muley, but with no prior Mule 3 experience, would you be able to create Mule applications? I was faced with this issue when I was working on a project using Mule 3. This blog post, I’d like to write about my experience and discuss some of the significant differences in Mule 3 I found.
DataWeave 1.0 Vs DataWeave 2.0
Let’s examine the changes that have been made to DataWeave. Mule 3 uses Mule Expression Language (MEL) to evaluate the data contained in variables, properties and payload. DataWeave 1.0 can be used to create messages. There are many evaluation tools that use MEL to process diverse inputs, such as Groovy or JSON. Users need to transform their binary data into Java objects in order to gain access to the data.
In Mule 3, I had to convert the payload from string to print it in Logger. Transform Message is a component that is able to alter input data after it has been converted into an object. With Mule 4, everything is much simpler. The data that is received is recognized instantly, which means there is no need to convert it.
When working using Mule 3, be aware that the syntax of code differs in comparison to Mule 4. I strongly recommend the MuleSoft online document. It contains everything you need to set up different components as well as learn how certain functions function in DataWeave 1.0. This information is essential when making a transformation code to your data. Check out this MuleSoft tutorial for beginners in telugu to learn more.
Error handling
The Mule 3 error handling is a part of Mule 3, the error handling is composed from Java handlers for exceptions. It provides details about the specifics of the error that is thrown.
There are five other exception strategies:
Catch an exception strategy.
Strategy for avoiding exceptions by choice.
Reference strategy for exceptions.
Rollback exception strategy.
Default exception strategy.
In Mule 4 The Java Throwables are still available however, their error management mechanism built upon that of the Mule runtime engine’s error handling. If there’s an error being thrown into the component. In that situation all information about the error will include the error’s type as well as all its primary characteristics.
There are three error handling strategies within Mule 4:
Default error handler,
On error propagate scope,
On error continue scope.
As part of the course of my Mule 3 application, I needed to send the error message that was received from the Process API to the System API and include the success response. To accomplish this I had to first extract the error information from the error, and then implement a Catch the exception technique. For Mule 4, I could only utilize the Error Continue error handler.
Therefore, the concept of error handling is different for Mule 3 and Mule 3. For Mule 3, it is composed from JavaException Handling and the process in Mule 4, error handling is Mule specific. Also, MuleSoft documentation is an excellent source of information detailing how to build an error-handling strategy that is appropriate for the Mule 3 application.
Message models
A different aspect is model messages. The model message in Mule 4, a message is composed of attributes, payload , and variables. When using Mule 3, the message is contained within the message object. It comprises a head (Inbound properties and outbound) as well as a payload. It’s certainly more complex when compared to Mule 3. Because of its intricate structure, it’s more difficult to extract the necessary information from the metadata available in Mule 3. When creating an Mule 3 application, the metadata required to build applications may not be stored in a single spot.
Maven and project structure
The moment I realized that I didn’t have a pom-file I was stunned! In Mule 3 there are two kinds of projects: Mule project and MuleSoft application which includes Maven project. The Mule 4 version has the Maven project as well. Mule 4, all projects are automatically mavenized. Anypoint Studio, released with Mule 4, has Maven embedded, but this isn’t the case with Mule 3. In addition it is the case that in Mule 3, an application is a zip-based package that can be distributed but it is in Mule 4, it is a jar file that is able to be deployed and shared.
The most important thing to keep in mind is that if you wish for the Mule 3 project to have a pom file, you must make it by yourself. Mavenize your projects by selecting the project’s name. Then, click on Mule > Mavenize, as shown in the following image. The dependencies of your project will be generated by default.
Anypoint Studio
The final thing that caught my focus within Mule 4 was Anypoint Studio. The flow options within Mule 3 are not collapsible and there’s no option to build an individual palette. There are icons for the components that are different as well. These are minor tweaks but not to the point that one has to learn how to navigate within Anypoint Studio released with Mule 4.
Conclusion
It was a challenge to adjust the working environment of Mule 3 and learn these differentiators between the versions. The development of apps using Mule 3 without a Mule 3 certification is going to take longer. My opinion is that Mule 4 is more language-agnostic in regards to prerequisites needed for MuleSoft online training India. Mule 3, on the other hand, appears to be more Java-oriented. However, learning about the distinctions has been a wonderful experience. It was fascinating to observe how Mule has changed.
Beginning using Mule 3? Take a look at Mule 3’s documentation. Mule 3 documentation. There’s plenty of information on how to build your app. I found the provided examples about the configuration of components extremely useful. Also, don’t overlook that you can also visit the MuleSoft Help forum which has hundreds of questions on Mule 3 or Mule 4 differences answered by the top MuleSoft experts. Have fun!
