Taking Apache Camel
For a Ride
Bruce Snyder
bsnyder@apache.org
3 June 2008 1

Integration is Messy!
2

System Integration
3

Data Formats
4

Apache Camel
http://activemq.apache.org/camel/
5

What is
Apache
Camel?
6

Enterprise Integration Patterns
http://enterpriseintegrationpatterns.com/
7

Patterns
8

Message Routing
9

Language Support
• BeanShell • SQL
• Javascript • XPath
• Groovy • XQuery
• Python • OGNL
• PHP • JSR 223 scripting
• Ruby
10

Apache Camel Components
http://activemq.apache.org/camel/components.html
11

History of Apache Camel
12

The Camel Context
CamelContext context = new DefaultCamelContext();
context.addRoutes(new MyRouteBuilder());
context.start();
<camelContext
xmlns=\"http://activemq.apache.org/camel/schema/spring\">
<package>com.acme.quotes</package>
</camelContext>
13

Pattern
Examples
14

Patterns Again
15

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\");
}
};
16

Content Based Router
<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>
17

Message Filter
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"activemq:topic:Quotes).
filter().xpath(\"/quote/product = ‘widget’\").
to(\"mqseries:WidgetQuotes\");
}
}
18

Message Filter
<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>
19

Splitter
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"file://orders\").
splitter(body().tokenize(\"\\n\")).
to(\"activemq:Order.Items\");
}
}
20

Splitter Using XQuery
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"file://orders\").
splitter().xquery(\"/order/items\").
to(\"activemq:Order.Items\");
}
}
21

Aggregator
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"activemq:Inventory.Items\").
aggregator().xpath(\"/order/@id\").
to(\"activemq:Inventory.Order\");
}
}
22

Message Translator
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"file://incoming”).
to(\"xslt:com/acme/mytransform.xsl\").
to(\"http://outgoing.com/foo\");
}
}
23

Resequencer
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"direct:a”).
resequencer(header(\"JMSPriority\")).
to(\"seda:b\");
}
}
24

Throttler
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"seda:a”).
throttler(3).timePeriodMillis(30000).
to(\"seda:b\");
}
}
25

Delayer
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"seda:a”).
delayer(header(\"JMSTimestamp\", 3000).
to(\"seda:b\");
}
}
26

Combine Patterns
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"seda:a”).
resequencer(header(\"JMSPriority\")).
delayer(3000).
to(\"seda:b\");
}
}
27

Beans
28

Bean
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>
29

Bean as a Message Translator
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"activemq:Incoming”).
beanRef(\"myBean\").
to(\"activemq:Outgoing\");
}
}
30

Bean as a Message Translator
*With Method Name
public class MyRouteBuilder extends RouteBuilder {
public void configure() {
from(\"activemq:Incoming”).
beanRef(\"myBean\", \"someMethod\").
to(\"activemq:Outgoing\");
}
}
31

Type Conversion
32

Type Conversion
@Converter
public class IOConverter {
@Converter
public static InputStream toInputStream(File file)
throws FileNotFoundException {
return new BufferedInputStream(
new FileInputStream(file));
}
}
33

Binding Beans to Camel Endpoints
public class Foo {
@MessageDriven(uri=\"activemq:cheese\")
public void onCheese(String name) {
...
}
}
34

Binding Method Arguments
public class Foo {
public void onCheese(
@XPath(\"/foo/bar\") String name,
@Header(\"JMSCorrelationID\") String id) {
...
}
}
http://activemq.apache.org/camel/bean-integration.html
35

Injecting Endpoints Into Beans
public class Foo {
@EndpointInject(uri=\"activemq:foo.bar\")
ProducerTemplate producer;
public void doSomething() {
if (whatever) {
producer.sendBody(\"<hello>world!</hello>\");
}
}
}
36

Spring Remoting - Server Side
<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\"/>
37

Spring Remoting - Client Side
<camelContext
xmlns=\"http://activemq.apache.org/camel/schema/spring\">
<proxy id=\"sayService\" serviceUrl=\"activemq:MyService\"
serviceInterface=\"com.acme.MyServiceInterface\"/>
</camelContext>
38

Dependency Injection
<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>
39

Business Activity Monitoring (BAM)
40

Business Activity Monitoring (BAM)
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\");
}
}
41

Ride the Camel!
42

Questions?
43