Taking Apache Camel For a Ride

Bruce Snyder11 April 2008

Amsterdam, The Netherlands

System Integration

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Apache Camel

http://activemq.apache.org/camel/

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What is Apache Camel?

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Enterprise Integration Patterns

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http://enterpriseintegrationpatterns.com/6

Patterns

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Message Routing

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Language Support

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• BeanShell• Javascript• Groovy• Python• PHP• Ruby

• SQL• XPath• XQuery• OGNL• JSR 223 scripting

Apache Camel Components

http://activemq.apache.org/camel/components.html10

History of Apache Camel

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The Camel Context

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <package>com.acme.quotes</package></camelContext>

CamelContext context = new DefaultCamelContext();context.addRoutes(new MyRouteBuilder());context.start();

Pattern Examples

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Patterns Again

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Content Based Router

RouteBuilder builder = new RouteBuilder() { public void configure() { from("seda:a").choice().when(header("foo") .isEqualTo("bar")).to("seda:b") .when(header("foo").isEqualTo("cheese")) .to("seda:c").otherwise().to("seda:d"); } };

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <route> <from uri="activemq:NewOrders"/> <choice> <when> <xpath>/order/product = 'widget'</xpath> <to uri="activemq:Orders.Widgets"/> </when> <when> <xpath>/order/product = 'gadget'</xpath> <to uri="activemq:Orders.Gadgets"/> </when> <otherwise> <to uri="activemq:Orders.Bad"/> </otherwise> </choice> </route> </camelContext>

Content Based Router

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Message Filter

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("activemq:topic:Quotes). filter().xpath("/quote/product = ‘widget’"). to("mqseries:WidgetQuotes"); }}

Message Filter

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <route> <from uri="activemq:topic:Quotes"/> <filter> <xpath>/quote/product = ‘widget’</xpath> <to uri="mqseries:WidgetQuotes"/> </filter> </route> </camelContext>

Splitter

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("file://orders"). splitter(body().tokenize("\n")). to("activemq:Order.Items"); }}

Splitter Using XQuery

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("file://orders"). splitter().xquery("/order/items"). to("activemq:Order.Items"); }}

Aggregator

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("activemq:Inventory.Items"). aggregator().xpath("/order/@id"). to("activemq:Inventory.Order"); }}

Message Translator

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("file://incoming”). to("xslt:com/acme/mytransform.xsl"). to("http://outgoing.com/foo"); }}

Resequencer

public class MyRouteBuilder extends RouteBuilder { public void configure() { from("direct:a”). resequencer(header("JMSPriority")). to("seda:b"); }}

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Throttlerpublic class MyRouteBuilder extends RouteBuilder { public void configure() { from("seda:a”). throttler(3).timePeriodMillis(30000). to("seda:b"); }}

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Delayerpublic class MyRouteBuilder extends RouteBuilder { public void configure() { from("seda:a”). delayer(header("JMSTimestamp", 3000). to("seda:b"); }}

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Combine Patternspublic class MyRouteBuilder extends RouteBuilder { public void configure() { from("seda:a”). resequencer(header("JMSPriority")). delayer(3000). to("seda:b"); }}

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Beans

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Bean

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package com.mycompany.beans;

public class MyBean {

public void someMethod(String name) { ... }}

<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <package>com.mycompany.beans</package></camelContext>

Bean as a Message Translator

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("activemq:Incoming”). beanRef("myBean"). to("activemq:Outgoing"); }}

Bean as a Message Translator

With Method Name

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public class MyRouteBuilder extends RouteBuilder { public void configure() { from("activemq:Incoming”). beanRef("myBean", "someMethod"). to("activemq:Outgoing"); }}

Type Conversion

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Type Conversion

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@Converterpublic class IOConverter {

@Converter public static InputStream toInputStream(File file) throws FileNotFoundException { return new BufferedInputStream(

new FileInputStream(file)); }}

Binding Beans to Camel Endpoints

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public class Foo {

@MessageDriven(uri="activemq:cheese") public void onCheese(String name) { ... }}

Binding Method Arguments

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public class Foo {

public void onCheese( @XPath("/foo/bar") String name, @Header("JMSCorrelationID") String id) { ... }}

http://activemq.apache.org/camel/bean-integration.html

Injecting Endpoints Into Beans

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public class Foo { @EndpointInject(uri="activemq:foo.bar") ProducerTemplate producer;

public void doSomething() { if (whatever) { producer.sendBody("<hello>world!</hello>"); } }}

Spring Remoting - Client Side

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <proxy id="sayService" serviceUrl="activemq:MyService" serviceInterface="com.acme.MyServiceInterface"/></camelContext>

Spring Remoting - Server Side

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> <export id="sayService" uri="activemq:MyService" serviceRef="sayImpl" serviceInterface="com.acme.MyServiceInterface"/></camelContext>

<bean id="sayImpl" class="com.acme.MyServiceImpl"/>

Dependency Injection

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<camelContext xmlns="http://activemq.apache.org/camel/schema/spring"> ...</camelContext>

<bean id="activemq" class="org.apache.camel.component.jms.JmsComponent"> <property name="connectionFactory"> <bean class="org.apache.activemq.ActiveMQConnectionFactory"> <property name="brokerURL" value="vm://localhost?broker.persistent=false"/> </bean> </property></bean>

Business Activity Monitoring (BAM)

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public class MyActivities extends ProcessBuilder {

public void configure() throws Exception {

// lets define some activities, correlating on an // XPath query of the message body ActivityBuilder purchaseOrder = activity("activemq:PurchaseOrders") .correlate(xpath("/purchaseOrder/@id").stringResult());

ActivityBuilder invoice = activity("activemq:Invoices") .correlate(xpath("/invoice/@purchaseOrderId").stringResult());

// now lets add some BAM rules invoice.starts().after(purchaseOrder.completes()) .expectWithin(seconds(1)) .errorIfOver(seconds(2)).to("activemq:FailedProcesses"); }}

Business Activity Monitoring (BAM)

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Ride the Camel!

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Questions?

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