Understanding Apache Camel EIP - Routing Slip Using Example | JavaInUse







Routing Slip EIP Pattern in Apache Camel using example

In previous tutorials EIP patterns using Apache Camel and Splitter and Aggregator pattern we have tried to understand various EIP patterns.
In this tutorial we will try to understand the Routing Slip Enterprise Integration Patterns using Camel Example.

Apache Camel Routing Slip EIP Pattern Tutorial

Apache Camel - Table of Contents

File Transfer Using Java DSL Apache Camel Apache Camel Java DSL + Spring Integration Hello World Example Apache Camel Exception Handling Using Simple Example Apache Camel Redelivery policy using example Integrate Apache Camel and ActiveMQ EIP patterns using Apache Camel Apache Camel Tutorial- Integrate Spring Boot+ Apache Camel Apache Camel Tutorial- Integrate with MySQL DB using SQL query Apache Camel + Spring + ActiveMQ + JBoss Fuse Apache Camel EIP - Splitter and Aggregator pattern Apache Camel Unit Testing Apache Camel + Spring + Quartz Hello World Example Camel application deployment on JBoss Fuse Apache Camel + Apache CXF SOAP Webservices Apache Camel + JAX-RS REST Webservice Apache Camel + CXFRS REST Webservice Apache Camel Routing Slip EIP Pattern Apache Camel Dynamic Router Pattern Apache Camel Load Balancer EIP Pattern Apache Camel Interceptors Apache Camel + Kafka Hello World Example Apache Camel - Marshalling/Unmarshalling XML/JSON Data Example

Video

This tutorial is explained in the below Youtube Video.

Lets Begin

We will create Eclipse maven project as follows-

Apache Camel Routing Slip EIP Pattern Example
Our pom file will be as follows-
<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/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.javainuse</groupId>
	<artifactId>camel-routingslip</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<dependencies>
		<dependency>
			<groupId>org.apache.camel</groupId>
			<artifactId>camel-core</artifactId>
			<version>2.13.0</version>
		</dependency>
	</dependencies>
</project>
Next we create a class to construct a Camel Routes. The Routing Slip from the EIP patterns allows you to route a message consecutively through a series of processing steps where the sequence of steps is not known at design time and can vary for each message. In the below example we set the routing slip to execute the flow in the following sequence -
route3->route2->route1
package com.javainuse;

import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.builder.RouteBuilder;

public class SimpleRouteBuilder extends RouteBuilder {

	@Override
	public void configure() throws Exception {
		from("file:C:/inbox?noop=true").split().tokenize("\n").process(new Processor() {
			public void process(Exchange exchange) {
				String body = exchange.getIn().getBody().toString();
				String response;
				if (body.contains("javainuse1")) {
					// the following routes will be called sequentially
					response = "direct:route1,direct:route2,direct:route3";
				} else
					// the following routes will be called sequentially
					response = "direct:route3,direct:route2,direct:route1";
					//set the route slip message in the header
				exchange.getIn().setHeader("myRoutingSlipHeader", response);
			}
		}).routingSlip(header("myRoutingSlipHeader"));

		from("direct:route1").process(new Processor() {
			public void process(Exchange exchange) {
				String body = exchange.getIn().getBody().toString();
				body = body + " in route 1";
				System.out.println(body);
				exchange.getOut().setBody(body);
			}
		});

		from("direct:route2").process(new Processor() {
			public void process(Exchange exchange) {
				String body = exchange.getIn().getBody().toString();
				body = body + " in route 2";
				System.out.println(body);
				exchange.getOut().setBody(body);
			}
		});

		from("direct:route3").process(new Processor() {
			public void process(Exchange exchange) {
				String body = exchange.getIn().getBody().toString();
				body = body + " in route 3";
				exchange.getOut().setBody(body);
				System.out.println(body);
			}
		});
	}
}
When Camel is started, it creates a CamelContext object that contains the definition of the Route to be started. Below we create default camel context and load the routes created in SimpleRouteBuilder.
package com.javainuse;

import org.apache.camel.CamelContext;
import org.apache.camel.impl.DefaultCamelContext;

public class MainApp {

    public static void main(String[] args) {
        SimpleRouteBuilder routeBuilder = new SimpleRouteBuilder();
        CamelContext ctx = new DefaultCamelContext();
        try {
            ctx.addRoutes(routeBuilder);
            ctx.start();
            Thread.sleep(5 * 60 * 1000);
            ctx.stop();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

    }
}
Next run the MainApp class as a java application-
Apache Camel Routing Slip EIP Pattern

Download Source Code

Download it - Apache Camel Routing Slip EIP Pattern

See Also

Spring Boot Hello World Application- Create simple controller and jsp view using Maven Spring Boot Tutorial-Spring Data JPA Spring Boot + Simple Security Configuration Pagination using Spring Boot Simple Example Spring Boot + ActiveMQ Hello world Example Spring Boot + Swagger Example Hello World Example Spring Boot + Swagger- Understanding the various Swagger Annotations Spring Boot Main Menu Spring Boot Interview Questions