The document discusses validation in Mule applications using the Validations module. It provides an example Mule flow that uses the <validation:is-not-empty> validator to check for an empty name parameter in the HTTP request. If name is empty, a ValidationException is thrown with a custom error message. Running the flow with or without the name parameter demonstrates a success or failure case.

1. Validation

2. Abstract
• The main motto of this PPT is How to use
Validation in our applications.

3. Introduction
• The Validations module provides an easy out-of-
the-box way to verify that the content of a
message in your flow matches a given set of
criteria. The main advantage this has over
using Filters is traceability, as filters all raise
identical exceptions, making it hard for you to
know where the exception was caused.
Validators, on the other hand, raise an exception
with a meaningful message attached. You can
optionally customize this message and even the
type of exception you want it to throw.

4. Example

6. .mflow
• <?xml version="1.0" encoding="UTF-8"?>
• <mule xmlns:validation="http://www.mulesoft.org/schema/mule/validation"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns="http://www.mulesoft.org/schema/mule/core"
xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
• xmlns:spring="http://www.springframework.org/schema/beans"
• xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
• xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-current.xsd
• http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
• http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
• http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-
context-current.xsd
• http://www.mulesoft.org/schema/mule/validation
http://www.mulesoft.org/schema/mule/validation/current/mule-validation.xsd">
• <http:listener-config name="HTTP_Listener_Configuration" host="${host}" port="${port}" doc:name="HTTP
Listener Configuration"/>
• <context:property-placeholder location="myfile-${env}.properties"/>
• <flow name="PropertyPlaceHolderFlow">
• <http:listener config-ref="HTTP_Listener_Configuration" path="/" doc:name="HTTP"/>
• <validation:is-not-empty value="#[message.inboundProperties.'http.query.params'.name]"
doc:name="Validation"/>
• <logger message="--Hello" level="INFO" doc:name="Logger"/>
• </flow>
• </mule>

7. • Output:
• ERROR 2016-12-21 11:36:25,918
[[PropertyPlaceHolder].HTTP_Listener_Configuration.worker.01]
org.mule.exception.DefaultMessagingExceptionStrategy:
• *******************************************************************
*************
• Message : value is null
• Payload : {NullPayload}
• Payload Type : org.mule.transport.NullPayload
• Element : /PropertyPlaceHolderFlow/processors/0 @ PropertyPlaceHolder
• --------------------------------------------------------------------------------
• Root Exception stack trace:
• org.mule.extension.validation.api.ValidationException: value is null
• at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
• at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
• at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
• at java.lang.reflect.Constructor.newInstance(Unknown Source)

8. • Flow of execution:
1. URL to trigger the service from browser
http://localhost:8086 – Failure
http://localhost:8086?name=hi - Success
Note:
1. Create myfile-DEV.proerties file in
src/main/resources folder
2. Specify the env name in mule-app.properties file

9. References
• https://docs.mulesoft.com/mule-user-
guide/v/3.7/validations-module