This document discusses how to access variables in Groovy scripts and Java code within Mule applications. There are two types of variables in Mule: flow variables, which are limited to a specific flow, and session variables, which are global to the entire application. The document provides examples of how to retrieve variable values using different methods like getInvocationProperty() and getSessionProperty() in Groovy, and set variables using setProperty() and setSessionProperty(). It demonstrates retrieving variables set in a Mule flow and also setting variables in Groovy scripts to be accessed in flows.

1. By Anirban Sen Chowdhary

2. We have often seen that people asking how the variables can be accessed in Groovy Script or
Java..
Well, accessing variables in Groovy Script or Java are almost in same way and we will see a
simple demo of doing it.

3. But before we start, we will be seeing what are the variables we have in Mule…
Mule basically have 2 types of variables:-
• Flow variables :- Flow variables are the variables in Mule whose scope is limited to a flow
or a sub flow and whose values doesn’t cross outside a flow level.
• Session variables :- Session variables are basically global variable in that application and
it’s scope is all over the flow declared or designed in the application. Session variables
can be declared in any flow and can be accessed from any other flow or sub flow

4. Now, let’s see how can we access a Session variable and a Flow variable from a Groovy
script..
Let’s consider we have defined a Session variable and a Flow variable in our flow as follow
:-
<set-variable variableName="myflowVariable" value="TestFlowVariable" doc:name="Variable"/>
<set-session-variable variableName="mysessionVariable" value="TestSessionVariable"
doc:name="Session Variable"/>
Now, we will see how to retrieve these values in Groovy script

5. Now, we can use the following to retrieve a Flow variables in a Groovy script :-
message.getInvocationProperty('myflowVariable')
Or
message.getProperty("myflowVariable", org.mule.api.transport.PropertyScope.INVOCATION)
Or simply
flowVars['myflowVariable']
Any of the above code will retrieve the value of Flow variables in Groovy

6. Similarly we can use the following to retrieve a Session variable in a Groovy script :-
message.getSessionProperty('mysessionVariable')
Or
message.getProperty(" 'mysessionVariable ", org.mule.api.transport.PropertyScope.SESSION)
Or simply
sessionVars['mysessionVariable ']
Any of the above code will retrieve the value of Session variables in Groovy

7. So, let’s test our application… our Mule flow will be as follows :-
You can see we are setting the variables in the flow and we will be retrieving the values in
the Groovy scripts and print it in logger

8. So, if we test the application we will get the Session variable and Flow variables values in
console as follows :-
So we are getting the values of the Session variable and Flow variables with all the method
we have used in Groovy
We can use the same methods in our Java class to retrieve the values of variables

9. So, now we will look to set variables from Groovy script and access it in flow :-
You can set the Flow variables in Groovy using the following syntax :-
message.setProperty('key', 'value', org.mule.api.transport.PropertyScope.INVOCATION);
or
message.setInvocationProperty('key','value');

10. And you can set the Session variables in Groovy using the following syntax :-
message.setProperty('key', 'value', org.mule.api.transport.PropertyScope.SESSION);
or
message.setSessionProperty('key','value');

11. Now, lets design our flow again and this time we will be setting the variables in Groovy and
access it in flow using loggers. You can easily see we are setting the variables (both Session
variable and Flow variable) in 2 different ways for each variable. You can use any one
method out of 2

12. In logger we can see the values of the variables
So, this is the way you can read as well as set variables (both Session variable and Flow
variable) in Groovy or Java

13. In my next slide I will bring some other techniques in Mule
implementation .
Hope you have enjoyed this simpler version.
Keep sharing your knowledge and let our Mule community grow 