Specifying a default exception strategy
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The document discusses how to specify a default exception strategy in Mule applications. It provides an example of a flow that handles exceptions, showing how to configure a global catch-exception strategy that sets a 400 status code and error payload if any exceptions occur. It also shows sample output when the flow receives valid versus invalid input.
![.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="{
• "token":"#[message.outboundProperties.token]"
• }" doc:name="Set Payload"/>
• </flow>
• </mule>](https://image.slidesharecdn.com/specifyingadefaultexceptionstrategy-161223100457/85/Specifying-a-default-exception-strategy-7-320.jpg)
![• Output:
• If the input is valid input:
• INFO 2016-12-23 10:03:37,163
[[ExceptionHandling].HTTP_Listener_Configuratio
n.worker.01]
org.mule.api.processor.LoggerMessageProcessor:
-Flow started
• INFO 2016-12-23 10:03:37,233
[[ExceptionHandling].HTTP_Listener_Configuratio
n.worker.01]
org.mule.api.processor.LoggerMessageProcessor:
--Token value: ----a1b2c3d4](https://image.slidesharecdn.com/specifyingadefaultexceptionstrategy-161223100457/85/Specifying-a-default-exception-strategy-9-320.jpg)
![• If the input is invalid input:
• INFO 2016-12-23 10:04:02,030 [[ExceptionHandling].HTTP_Listener_Configuration.worker.02]
org.mule.api.processor.LoggerMessageProcessor: -Flow started
• ERROR 2016-12-23 10:04:02,072 [[ExceptionHandling].HTTP_Listener_Configuration.worker.02]
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)](https://image.slidesharecdn.com/specifyingadefaultexceptionstrategy-161223100457/85/Specifying-a-default-exception-strategy-11-320.jpg)
Specifying a default exception strategy
- 1. Specifying a default exception strategy
- 2. Abstract • The main motto of this PPT is How to use Specifying a default exception strategy in our applications.
- 3. Example
- 7. .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="{ • "token":"#[message.outboundProperties.token]" • }" doc:name="Set Payload"/> • </flow> • </mule>
- 8. • Global flow: • <?xml version="1.0" encoding="UTF-8"?> • <mule xmlns:cluster="http://www.mulesoft.org/schema/mule/ee/cluster" 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"> • <configuration defaultExceptionStrategy-ref="GlobalCatch_Exception_Strategy" doc:name="Configuration"> • <http:config useTransportForUris="false"/> • </configuration> • <catch-exception-strategy name="GlobalCatch_Exception_Strategy"> • <set-property propertyName="http.status" value="400" doc:name="Property"/> • <set-payload value="{ • "message":"Bad Request" • }" doc:name="Set Payload"/> • </catch-exception-strategy> • </mule>
- 9. • Output: • If the input is valid input: • INFO 2016-12-23 10:03:37,163 [[ExceptionHandling].HTTP_Listener_Configuratio n.worker.01] org.mule.api.processor.LoggerMessageProcessor: -Flow started • INFO 2016-12-23 10:03:37,233 [[ExceptionHandling].HTTP_Listener_Configuratio n.worker.01] org.mule.api.processor.LoggerMessageProcessor: --Token value: ----a1b2c3d4
- 11. • If the input is invalid input: • INFO 2016-12-23 10:04:02,030 [[ExceptionHandling].HTTP_Listener_Configuration.worker.02] org.mule.api.processor.LoggerMessageProcessor: -Flow started • ERROR 2016-12-23 10:04:02,072 [[ExceptionHandling].HTTP_Listener_Configuration.worker.02] 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)