The Mule Expression Transformer allows evaluating one or more expressions on the current message. Each evaluated expression results in a parameter in the returned message. If there are multiple expressions, the results are returned as an object array. It can be configured through a wizard, specifying things like the display name, return class, encoding, MIME type, and expressions to transform message data. The transformer also supports adding multiple evaluators to intercept and transform message properties.

1. Mule Expression Transformer
BY : Nagarjuna Reddy

2. What does Expression Transformer do?
An Expression Transformer evaluates one or more
expressions on the current message. Each evaluated
expression equates to a parameter in the returned message.
However, if the returned message encompasses more than
one expression, then the results of those expressions are an
Object array.
The Expression Transformer has the same advanced
properties as all other transformers with the addition of an
optional list of return arguments.

3. Mule Expression Transformer – Configuration
Wizard (General Tab) (Cont.)

4. Mule Expression Transformer –
Configuration Wizard (General Tab)
 Following are the options in general tab –
 Display Name – This attribute takes the name of the component to be displayed in
Mule flow.
 Return Class – This attribute takes the class whose object will be returned after
transformation.
 Encoding – This attribute takes the encoding standard to be applied on message
data.
 MIME Type This attribute takes the MIME Type of the message data e.g.
application/xml.
 Expression – This attributes takes the expression to be used to transform the
message data.

5. Mule Expression Transformer – Configuration
Wizard (Advanced Tab) (Cont.)

6. Mule Expression Transformer –
Configuration Wizard (Advanced Tab)
 User can add multiple evaluators that can intercept message properties,
transform them according to an expression and then return the transformed
value.

7. Mule Expression Transformer – Configuration
Wizard (Notes and Meta-Data TAbs)
 Notes Tab – Notes tab is used to add special notes to Mule Expression
Transformer.
 META-DATA Tab – Meta-Data Tab is used to add meta-data to Mule Expression
Transformer.

8. Thank You!