This document discusses defining global exception strategies in Mule applications. It provides an example Mule flow that references a global catch exception strategy, which sets a 400 status code and error payload when exceptions occur. The example shows log output for valid and invalid token inputs, with the invalid input triggering the global exception strategy. References are provided to the Mule documentation on error handling.

1. Defining global exception strategies

2. Abstract
• The main motto of this PPT is How to use
Defining global exception strategies in our
applications.

3. Example

5. .mflow
• <?xml version="1.0" encoding="UTF-8"?>
• <mule 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:listener-config name="HTTP_Listener_Configuration" host="localhost" port="8088" doc:name="HTTP
Listener Configuration"/>
• <flow name="ExceptionHandlingFlow">
• <http:listener config-ref="HTTP_Listener_Configuration" path="/" doc:name="HTTP"/>
• <logger message="-Flow started" level="INFO" doc:name="Logger"/>
• <set-property propertyName="token"
value="#[message.inboundProperties.'http.query.params'.token.toString()]" doc:name="Property"/>
• <logger message="--Token value: ----#[message.outboundProperties.token]" level="INFO"
doc:name="Logger"/>
• <set-payload value="{
• &quot;token&quot;:&quot;#[message.outboundProperties.token]&quot;
• }" doc:name="Set Payload"/>
• <exception-strategy ref="GlobalCatch_Exception_Strategy" doc:name="Reference Exception Strategy"/>
• </flow>
• </mule>

6. • Global flow:
• <?xml version="1.0" encoding="UTF-8"?>
• <mule 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">
• <catch-exception-strategy name="GlobalCatch_Exception_Strategy">
• <set-property propertyName="http.status" value="400" doc:name="Property"/>
• <set-payload value="{
• &quot;message&quot;:&quot;Bad Request&quot;
• }" doc:name="Set Payload"/>
• </catch-exception-strategy>
• </mule>

7. • Output:
• If the input is valid input:
• INFO 2016-12-23 09:50:35,930
[[ExceptionHandling].HTTP_Listener_Configuratio
n.worker.01]
org.mule.api.processor.LoggerMessageProcessor:
-Flow started
• INFO 2016-12-23 09:50:35,978
[[ExceptionHandling].HTTP_Listener_Configuratio
n.worker.01]
org.mule.api.processor.LoggerMessageProcessor:
--Token value: ----a1b2c3d4

9. • If the input is invalid input:
• NFO 2016-12-23 09:51:25,543 [[ExceptionHandling].HTTP_Listener_Configuration.worker.01]
org.mule.api.processor.LoggerMessageProcessor: -Flow started
• ERROR 2016-12-23 09:51:25,552 [[ExceptionHandling].HTTP_Listener_Configuration.worker.01]
org.mule.exception.CatchMessagingExceptionStrategy:
• ********************************************************************************
• Message : Execution of the expression
"message.inboundProperties.'http.query.params'.token.toString()" failed.
(org.mule.api.expression.ExpressionRuntimeException).
• Payload : {NullPayload}
• Element XML : <set-property propertyName="token"
value="#[message.inboundProperties.'http.query.params'.token.toString()]"
doc:name="Property"></set-property>
• Payload Type : org.mule.transport.NullPayload
• Element : /ExceptionHandlingFlow/processors/1 @
ExceptionHandling:ExceptionHandling.xml:13 (Property)
• --------------------------------------------------------------------------------
• Root Exception stack trace:
• java.lang.NullPointerException
• at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
• at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
• at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

11. References
• https://docs.mulesoft.com/mule-user-
guide/v/3.6/error-handling