Apache Camel Essential Components

Presenter: Christian PostaTitle: Senior ConsultantDate: January 23, 2013

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Agenda

FuseSource/Red Hat What is Camel? Camel Intro Components More Information Q & A

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FuseSource – the leading open source integration and messaging vendor...now a part of Red Hat!

FuseSource – a company built on success

Founded in 2005

Commercial Support Camel, ActiveMQ, ServiceMix, CXF

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Share a maniacal focus on community

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Same Great Products and Services – and More

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Continued training, consulting, and subscriptions – more coverage

fusesource.com transitioning to redhat.com

JIRAS → redhat.com Community – need to re-register at redhat.com fusesource.com - maintained at least through 2013

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About Me

Christian Posta Senior Consultant Committer at Apache on ActiveMQ, Apollo Email: christian@redhat.com

ceposta@apache.org Blog: http://www.christianposta.com/blog Twitter: @christianposta Google+

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What is Camel?

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What isn’t Apache Camel

• Enterprise Service Bus (ESB)

• Container

• ServiceMix/FuseESB

• OSGi container

• Tomcat, JBoss, Geronimo

• Commercial App Servers

• Proprietary, closed source

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Integration

Use Camel to Integrate disparate systems that talk different protocols and data formats.

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Integrate??

• Integration is Hard!

• Different system vintages

• Mainframe, EAI Hub, MOM, EJB, Web Services

• Evolving business processes

• Systems must work together

• File exchange, Shared Database, Remote Procedure Call (RPC), Messaging

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Why integration is hard…

• Platforms

• Protocols

• Data Formats

• Timing

• Organizational mismatch

• Communication

Hard, but not impossible, definitely not new…

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Patterns!

• Enterprise Integration Patterns (EIP)

• Specific context

• Forces at work

• Concrete solution

• Guidance for solutions to your problems

• 65 patterns• Content Based Router

• Splitter

• Aggregator

• Filter

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What is Apache Camel?

• Lightweight Integration Framework

• Open Source! (Apache Software Foundation)

• Routing and Mediation (like an ESB?)

• Enterprise Integration Patterns

• Components

• Domain Specific Language

• Runs in any container (or stand alone)

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Camel Intro

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Quick Example

File System Message Oriented Middleware

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Quick Example

From A Send to BFilter

message

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Quick Example

from(A) to(B)filter(predicate)

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Quick Example

from(A) .to(B).filter(isWidget)

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Quick Example

isWidget = xpath(“/quote/product = ‘widget’”);

from(A) .filter(isWidget). to(B)

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Quick Example

public class MyExampleRouteBuilder extends RouteBuilder {

@Override public void configure() throws Exception {

Predicate isWidget = xpath("/quote/product = ‘widget’");

from(“file:quote/location”).filter(isWidget).to(“jms:quote”);

}}

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Domain Specific Language

• Domain specific (integration)

• Used to build and describe Camel Routes

• Embedded within a general programming language

• Java, Spring XML, Scala, Groovy

• Take advantage of existing tools

• Fluent builders (builder pattern…)• from(“..”).enrich(“…”).filter(“..”).to(“…”);

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Pipes and Filters Architecture

• Step by Step

• Complex processing

• Flexible

• Testing

• Reuse

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Camel Routes

• Defined in Java, XML, Scala, Groovy

• Step by step processing of a message:

• Consumer – Listen for incoming message

• Zero or more “filters” or Processors

• Producer – Send outgoing message

• Number of processing filters, or “Processors” in Camel-speak

• EIPs

• Tranform, redirect, enrich

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Domain Specific Language

• Example Java DSL

from("file:src/data?noop=true”)

.choice()

.when(xpath("/person/city = 'London'"))

.to("file:target/messages/uk »)

.otherwise()

.to("file:target/messages/others");

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Domain Specific Language

• Example Spring XML DSL

<route> <from uri="file:src/data?noop=true” /> <choice> <when> <xpath>/person/city = 'London'</xpath>

<to uri="file:target/messages/uk” /> </when>

<otherwise> <to uri="file:target/messages/others" /> </otherwise> </choice></route>

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Components

• What is “file:src/data?noop=true” ??

• Prepackaged bits of code

• Highly configurable

• Used to build “Adapters” to existing systems

• Don’t reinvent the wheel and end up with a box

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Components…

• URI format:

• scheme:localPart[?options]

• scheme: identifies the “component”

• localPart: specific to the component

• options: is a list of name-value pairs

• Creates endpoints based on configuration

• Route endpoint “factories”

• Integrate with Camel Routes by creating producer/consumer endpoints

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Components…

• ActiveMQ, Websphere, Weblogic (JMS)

• AMQP

• ATOM feeds

• AWS (Amazon Web Services)

• Bean

• Cache (EHCache)

• CXF (JAX-WS, JAX-RS)

• EJB

• Drools

• File

• FTP

• Google App Engine

• GMail

• HTTP

• IRC

• jclouds

• JDBC

• Jetty

• Twitter

• MQTT

• MyBatis

• JPA

• Spring Integration

• Spring Web Services

http://camel.apache.org/components.html

To see list of all

components!!

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Essential Components

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

http://refcardz.dzone.com/refcardz/essential-camel-components

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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File Component (camel-core)

• File integrations still exist!

• Legacy systems

• Batch jobs

• Many third party libraries for interfacing with the filesystem

• Why write app-specific file-system code for every app?

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File Component (camel-core)

• How long would it take you to implement this:

• Periodically polls a predefined location

• Picks up files

• Sends them to a JMS queue?

• How about…

• URI format: file:path[?options]

from(“file:/location/path?move=.processed”).to(“jms:queueName”)

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File Component (camel-core)

• Reads and writes file to the file system

• Endpoint URIs

• UNIX, absolute path file:/directoryPath[?options]

• Windows absolute path file:C://directoryPath[?options]

• Relative path file:directoryPath[?options]

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File Component (camel-core)

• Default behavior

1. Read all files in directory

2. Create a new message

3. Process message through route

• Filenames starting with ‘.’ character are ignored

• File component is one of the most flexible components with many config options

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File Component configuration options

Option Default Description

delay 500ms Time to delay between polling

initialDelay 1000ms How long before polling starts

delete False Whether or not to delete the file after it’s been processed

doneFileName null This file must exist before Camel will process the files in the directory

fileName null Explicit filename to poll. Only processes if file exists

include null A {regex} that can specify patterns of files to process

exclude null A {regex} specifying patterns of files to ignore

preMove null Move files to sub-directory before processing

readLock markerFile Strategy for how to exclusively lock a file before processing

See http://camel.apache.org/file2.html for more

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File Component things to watch out

• Files are locked until route completes

• Files starting with “.” are ignored

• By default, when a file has been processed, Camel will move the file to .camel file unless a move=<location> option specified

• Moving/Deleting files will happen after routing

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File Examples

from("file://inbox?preMove=.inprogress&move=.done")

.to(“activemq:queue:myQueue");

from("direct:report")

.to("file://target/reports/?fileName=report.txt");

from("file://data?exclude=_.*")

.to("bean:handleData?method=processData");

from("file://data?sortBy=date:file:yyyyMMdd;file:name")

.to(“direct:sorted");

See http://camel.apache.org/direct.html for info on direct component

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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Bean Component (camel-core)

• Implements Service Activator EIP• http://www.eaipatterns.com/MessagingAdapter.html

• http://camel.apache.org/bean.html

• Allows connecting existing Java Bean/POJO logic to Camel route

Camel Route

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Bean Component (camel-core)

• Invoke method on Java object to process incoming message

• Endpoint URI format: bean:beanID[?options]• from(“direct:incoming”).to(“bean:enrichService”).to(“file:data/output”)

• Define your beans in the Spring Context as you would any bean

• <bean id="enrichService" class="com.christianposta.refcard.CreditService" />

• Binds message and/or headers to bean method parameters

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Bean Component (camel-core)

• Call using to(..) • from(“direct:incoming”).to(“bean:enrichService?method=getCreditScore”)

• from(“direct:incoming”).to(“bean:enrichService”)

• Call using .bean(…)• from(“direct:incoming”).bean(CreditService.class, “getCreditScore”)

• from(“direct:incoming”).bean(new CreditService(), “getCreditScore”)

• Call using .beanRef(…)• from(“direct:incoming”).beanRef(“enrichService”, “getCreditScore”)

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Bean Examples

public class CreditService {

public int getCreditScore(@XPath("/Borrower/BorrowerId") long borrowerId) { … body of impl here …

}}

from(“jms:incoming”).to(“bean:enrichService?method=getCreditScore”).to(“jms:outgoing”);

<bean id="enrichService” class="com.christianposta.refcard.CreditService" />

Custom class

Camel route using bean component

Spring bean definition

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Bean Component: How are methods matched?

• By configuration: ?method=getCreditScore

• Single method in class

• Message Header named CamelBeanMethodName

• Method with only one parameter

• @Handler annotation

• By type (following internal algorithm)

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Bean Component: How are parameters matched?

• Automatically binds method parameters

• public void getCreditScore(Exchange exchange)

• public void getCreditScore(@Header(“customerId”) String customerId)

• public void getCreditScore(Message message)

• public void getCreditScore(byte[] bytes)

• Expression languages (simple, UEL, OGNL, groovy)

• TypeConverters if possible to bind parameters

• Error if cannot convert exchange to param type

• See http://camel.apache.org/bean-binding.html

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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Log Component (camel-core)

• Always use logging in your route!

• Camel uses SLF4J

• Log4j

• Logback

• JDK Util Logging

• Log Component used for logging message exchanges and/or parts of an exchange

• Headers

• Body

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Log Component (camel-core)

• Log Component vs .log() DSL?

• Component logs exchanges

• DSL logs custom expressions

• Both allow you to specify log level

• Endpoint URI format: log:category[?options]

• category would be package name, eg. com.mycompanyname.project

• Options to control what part of the message is logged

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Log Component configuration options

Option Description

showAll Turns on all options, such as body, body type, headers, out message, strackTraces, etc.

showExchangeId Log the exchangeId

showBodyType Logs the Java type for the body of the In message

showBody Log the actual contents of the body

showHeaders Log all of the headers of the In message

See http://camel.apache.org/log.html for more

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Log Examples

from(“direct:incoming”).to(“log:org.apache.camel?level=INFO”).to(“jms:outgoingQueue”);

from(“direct:incoming”) .log(LoggingLevel.INFO, “We received a body: ${body}”) .to(“jms:outgoingQueue”);

Log Component

Log DSL

from(“direct:incoming”) .to(“log:org.apache.camellevel=INFO&showBody=false&showHeaders=true”) .to(“jms:outgoingQueue”);

from(“direct:incoming”) .to(“log:org.apache.camel?level=INFO&multiline=true”).to(“jms:outgoingQueue”);

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Log Examples

from(“direct:incoming”).to(“log:org.apache.camel?level=INFO”).to(“jms:outgoingQueue”);

Log Component

Exchange[ExchangePattern:InOut, Headers:{

breadcrumbId=ID-FusePostaMac-local-54392-1358803440276-0-9, CamelToEndpoint=bean://enrichService?method=getCreditScore, creditScore=400, LoanNumber=100001

}, BodyType:String, Body: <contents here … >

]

Log Output

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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JMS Component (camel-jms)

• Not part of camel-core, so must add additional maven dependency

<dependency>

<groupId>org.apache.camel<groupId>

<artifactId>camel-jms</groupId>

<version>${camel-version}</version>

</dependency>

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JMS Component (camel-jms)

• Used to connect to JMS compliant message broker

• Endpoint URI Format• jms:[temp:][queue:|topic:]DestinationName[?options]

• Configure a JmsComponent bean in Spring XML

• Replace the jms: prefix with the bean name of the JmsComponent bean

<bean id=”activemq" class=”org.apache.activemq.camel.component.ActiveMQComponent” > <property name=“brokerURL” value=“tcp://localhost:61616” /></bean>

from(“activemq:incoming”).process(…).to(“activemq:outgoing”);

Example

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JMS Component (camel-jms)

• Default destination is Queuefrom(“activemq:incoming”).process(…).to(“activemq:outgoing”);

• Specify explicitlyfrom(“activemq:queue:incoming”).process(…).to(“activemq:queue:outgoing”);

• Specify Topicfrom(“activemq:topic:incoming”).process(…).to(“activemq:topic:outgoing”);

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JMS Component (camel-jms)

• Pool your connections, sessions, consumers

• Set up connection pool

<bean id="jms" class="org.apache.camel.component.jms.JmsComponent">   <property name="configuration" ref="jmsConfig" /> < /bean>

<bean id="jmsConfig" class="org.apache.camel.component.jms.JmsConfiguration" >  <property name="connectionFactory" ref="jmsPooledConnectionFactory" />   <property name="cacheLevelName" value="CACHE_CONSUMER" /> < /bean>

<bean id="jmsPooledConnectionFactory" class="org.apache.activemq.pool.PooledConnectionFactory"      init-method="start" destroy-method="stop" >  <property name="maxConnections" value="2" />  <property name="connectionFactory" ref="jmsConnectionFactory" /> < /bean> 

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JMS Component configuration options

Option Default Description

asyncConsumer false Process messages asynchronously

concurrentConsumers 1 Number of concurrent consumers

cacheLevelName CACHE_AUTO

Determines what JMS objects to cache, Connections, Sessions, Consumers, None, Auto.

transacted true Use transacted sessions

clientId null Unique connection ID (used for duable sub)

durableSubscriptionName

null Subscriber name for durable subscriptions

disableReplyTo false Treat all messages as InOnly, ignore JMSReplyTo

replyTo null Default replyTo destination

Selector null Set the JMS selector

timeToLive null JMS time to live

See http://camel.apache.org/jms.html for more

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JMS Examples

Multiple consumers

Durable Subscriber

from(“jms:incomingQueue?concurrentConsumers=5”).bean(someBean).to(“jms:outgoingQueue”);

from(“jms”topic:incoming?clientId=1&durableSubscriptionName=foo1”).bean(someBean);

Selectors

from(“jms:incomingQueue?selector=headerName %3D ‘somevalue’”).to(“jms:outgoingQueue”);

Request Reply

from(“direct:incoming”).inOut().to(“jms:outgoingQueue”).to(“bean:someBean”);

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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CXF Component (camel-cxf)

• Not part of camel-core, so must add additional maven dependency

<dependency>

<groupId>org.apache.camel<groupId>

<artifactId>camel-cxf</groupId>

<version>${camel-version}</version>

</dependency>

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CXF Component (camel-cxf)

• Integrates with CXF web services framework

• Consumers (expose web service), Producers (consume web service)

• Endpoint URI format:• Address style: cxf:address[?options]

• Bean style: cxf:bean:beanName

• Address Style• No bean necessary, URI quite verbose, CXF config limited

• Bean Style• Compact, flexible config allows CXF interceptors, etc

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CXF bean endpoint configuration

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:cxf="http://camel.apache.org/schema/cxf" xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans.xsd http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd http://camel.apache.org/schema/cxf

http://camel.apache.org/schema/cxf/camel-cxf.xsd">

<cxf:cxfEndpoint id="helloWorldWS" wsdlURL="wsdl/HelloWorld.wsdl" serviceClass="org.apache.helloworld.HelloWorld" address=http://localhost:9090/helloworld

serviceName=“tns:HelloService” endpointName=“tns:SoapOverHttpEndpoint

> </cxf:cxfEndpoint>

Service Endpoint Interface

WSDL definition

Where to publish

from(“cxf:bean:helloWorldWS”).bean(“processWS”);

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CXF bean endpoint configuration

• Setting the serviceClass attribute

• In CXF, we set serviceClass to • The JAX-WS interface in web client endpoints

• The JAX-WS implementation class in web service endpoints because we want CXF to dispatch requests to our code

• In Camel routes, we set serviceClass to the JAX-WS interface for producers or consumers because we want Camel to process to requests

• Using JAX-WS annotations

• Can omit the wsdlUrl, serviceName, and endpointName attributes from endpoint bean

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CXF Address endpoint configuration

from(“cxf:http://localhost:9090/helloworld?

serviceClass=org.apache.helloworld.HelloWorld&wsldUrl=wsdl/

HelloWorld.wsdl&serviceName=tns:HelloService”).bean(“processW

S”);

• More verbose

• Clutters up the route by mixing details

• Useful for testing

• Cannot configure CXF details

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CXF Payload

• The dataFormat option can have one of the following values:• POJO – arguments bound to plain old java objects

• PAYLOAD – message payload <soap:body>

• MESSAGE – raw message, as InputStream

Address style

Bean style

from(“cxf:http://localhost:8080/?dataFormat=PAYLOAD”).bean(“processWS”);

from(“cxf:bean:helloWorldWS”).bean(“processWS”);

<cxf:cxfEndpoint id=“helloWorldWS” … > <cxf:properties> <entry key=“dataFormat” value=“MESSAGE”/> </cxf:properties></cxf:cxfEndpoint>

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Essential Components

• File (camel-core)

• Bean (camel-core)

• Log (camel-core)

• JMS (camel-jms)

• CXF (camel-cxf)

• Mock (camel-core)

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Mock Component (camel-mock)

• Powerful way to test your Camel routes• http://camel.apache.org/mock.html

• Uses Mocks

• Mocks vs Stubs? • http://martinfowler.com/articles/mocksArentStubs.html

• Provides declarative testing mechanism

• Declare

• Test

• Assert

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Mock Component (camel-mock)

• Endpoint URI format: mock:mockName[?options]

• Can use just the same as any endpoint:

from(“direct:incoming”)

.choice()

.when(header(“loanNumber”).isGreaterThan(12345))

.to(“mock:specialLoan”)

.when(header(“loanNumber”).isLessThan(12345))

.to(“mock:regularLoan”)

.to(“mock:outgoing”);

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Mock Component declare, test, assert

// look up the endpoint MockEndpoint resultEndpoint = context.resolveEndpoint(“mock:outgoing”,

MockEndpoint.class);

// set expectations resultEndpoint.expectedMessageCount(2);

// send some messages ...

// assert expectations resultEndpoint.assertIsSatisfied();

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Mock endpoint expectations

Expectation method Description

expectedMessageCount(int) The number of messages that must have come through this mock

expectedMinimumMessageCount(int) The minimum number of messages that must have come to this mock

expectedBodiesReceived(Object …) The list of bodies must have come through this mock

expectedHeadersReceived(Object …) The list of headers that must have come through this mock

expectsNoDuplicates(Expression) No duplicate messages based on the expression (usually a unique header)

See http://camel.apache.org/mock.html for more

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Mock endpoint expectations

• Can also set expectations on individual messages

• mockEndpoint.message(int).body()…

MockEndpoint mockEndpoint = getMockEndpoint(“mock:sink”);

mockEndpoint.message(0).body(String.class).contains("John Doe");

sinkEndpoint.message(0).header("loanNumber").isEqualTo(123456);

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More Information

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DZone Refcardz

• Camel Essential Components • http://refcardz.dzone.com/refcardz/essential-camel-components

• Essential EIP with Apache Camel• http://refcardz.dzone.com/refcardz/enterprise-integration

REFCARDZ

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Red Hat / Fuse Source

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Apache Community

• http://camel.apache.org

• Mailing list: users@camel.apache.org

• Nabble Archive: http://camel.465427.n5.nabble.com/Camel-Users-f465428.html

• Source code: http://svn.apache.org/viewvc/camel/trunk/

• Blogs, Articles, Examples• http://camel.apache.org/articles.html

• http://camel.apache.org/user-stories.html

• http://camel.apache.org/user-stories.html

• http://www.davsclaus.com

• http://www.christianposta.com/blog

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Camel In Action

• Published 2011

• Claus Ibsen and Jon Anstey

• Covers EIPs, DSL, Components, Transactions, Threading, Expressions, Error Handling, Monitoring, etc

• In depth, examples, source code

• Source code kept up to date!• http://code.google.com/p/camelinaction/

• http://www.davsclaus.com/2013/01/camel-in-action-2-years-later.html

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Contact Me

Email: christian@redhat.com

ceposta@apache.org Blog: http://www.christianposta.com/blog Twitter: @christianposta Google+

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Q & A