Using Apache Camel with Spring

[Dilip H Pashupathi]

Hi,
I have been learning the Apache Camel with "Camel In Action" book. I am total new bee to this. I was working with some of the application examples provided with the book. In that I am trying my hands on a particular example where the Custom Route Builder class is autowired and should be added to the camel context. But this is not working as expected. I have provided the code below. Please help.

1. OrderRouteBuilder.java

package camelinaction.order;

import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.springframework.stereotype.Component;

import org.apache.camel.builder.RouteBuilder;



/**
 * Created by dilip.pashupathi on 26-Aug-15.
 */
@Component
public class OrderRouteBuilder extends RouteBuilder{

	public OrderRouteBuilder(){}
	@Override
	public void configure() {
		// load file orders from src/data into the JMS queue
		from("file:src/data?noop=true").to("jms:incomingOrders");

		// content-based router
		from("jms:incomingOrders")
				.choice()
				.when(header("CamelFileName").endsWith(".xml"))
				.to("jms:xmlOrders")
				.when(header("CamelFileName").regex("^.*(csv|csl)$"))
				.to("jms:csvOrders")
				.otherwise()
				.to("jms:badOrders");

		// lets filter out the test messages
		from("jms:xmlOrders").filter(xpath("/order[not(@test)]"))
				.process(new Processor () {
					public void process(Exchange exchange) throws Exception {
						System.out.println("Received XML order: "
								+ exchange.getIn().getHeader("CamelFileName"));
					}
				});
	}
}

1. OrderRouterWithFilter

package camelinaction.order;

import javax.jms.ConnectionFactory;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.camel.CamelContext;
import org.apache.camel.component.jms.JmsComponent;
import org.apache.camel.impl.DefaultCamelContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class OrderRouterWithFilter {

    @Autowired
    OrderRouteBuilder orderRouteBuilder;

    public void work()throws Exception{
        // create CamelContext
        CamelContext context = new DefaultCamelContext ();

        // connect to embedded ActiveMQ JMS broker
        ConnectionFactory connectionFactory =
                new ActiveMQConnectionFactory("vm://localhost");
        context.addComponent("jms",
                JmsComponent.jmsComponentAutoAcknowledge(connectionFactory));

        // add our route to the CamelContext
        context.addRoutes(orderRouteBuilder);

        // start the route and let it do its work
        context.start();
        Thread.sleep(10000);

        // stop the CamelContext
        context.stop();
    }

    public static void main(String args[]) throws Exception {
      new OrderRouterWithFilter ().work ();
    }
}

3. beans.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd "> <context:component-scan base-package="camelinaction.order"/> <camelContext id="camel" xmlns="http://camel.apache.org/schema/spring"> <contextScan/> </camelContext> </beans>

4. Added attachment as Project Structure

I am using Apache Maven 3.2.3 as Build Tool for all the required jar configurations.

5. pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <properties> <camel-version>2.12.0</camel-version> </properties> <parent> <groupId>com.camelinaction</groupId> <artifactId>chapter2</artifactId> <version>1.0.0</version> </parent> <artifactId>chapter2-filter</artifactId> <name>Camel in Action :: Chapter 2 :: Message Filter</name> <dependencies> <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring-javaconfig</artifactId> <version>${camel-version}</version> </dependency> <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-core</artifactId> <version>${camel-version}</version> </dependency> <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring</artifactId> <version>${camel-version}</version> </dependency> <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-test-spring</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-jms</artifactId> <version>${camel-version}</version> </dependency> <dependency> <groupId>org.apache.activemq</groupId> <artifactId>activemq-all</artifactId> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> </dependency> </dependencies> <build> <plugins> <!-- Allows the example to be run via 'mvn compile exec:java' --> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <configuration> <includePluginDependencies>false</includePluginDependencies> </configuration> </plugin> </plugins> </build> </project>


Please help with this. Even with all these it's raising an NPE at context.addRoute(orderRouteBuilder) statement.

Exception in thread "main" java.lang.NullPointerException
	at org.apache.camel.impl.DefaultCamelContext.addRoutes(DefaultCamelContext.java:669)
	at camelinaction.order.OrderRouterWithFilter.work(OrderRouterWithFilter.java:61)
	at camelinaction.order.OrderRouterWithFilter.main(OrderRouterWithFilter.java:72)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

[Debanjan Sarkar]

Hi Dilip,
I am new to this also but this might help
Add the following code to your work() instead of CamelContext context = new DefaultCamelContext ();

ApplicationContext springcontext = new FileSystemXmlApplicationContext("src/main/resources/beans.xml");
CamelContext context = springcontext.getBean("camel", CamelContext.class);

Please let me know if that helped