EIP Patterns in Apache Camel using examples

In this tutorial we will try to understand the Enterprise Integration Patterns using Camel Examples. In previous tutorial have explained a simple example for integrating Apache camel and ActiveMQ where we created SimpleRouteBuilder.java and configure routes. Here will create multiple RouteBuilder classes to configure Routes according to the various EIP patterns

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 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
Calling and Consuming Webservices using Apache Camel
Apache Camel Tutorial - Send SMTP Email Using Gmail
Apache Camel Tutorial - SEDA component Hello World Example
Apache Camel Tutorial - Idempotent Consumer using MemoryIdempotentRepository and FileIdempotentRepository
Spring Boot + Apache Camel JDBC component + MySQL - Hello World Example 
Spring Boot + Apache Camel SQL component + MySQL - Hello World Example
Spring Boot + Apache Camel SQL component + Transaction Management Example

Lets Begin

• EIP- Splitter
  The Splitter from the EIP patterns allows users split a message into a number of pieces and process them individually.
  
  
  
  

  package com.javainuse;
  
  import org.apache.camel.builder.RouteBuilder;
  
  public class SimpleRouteBuilder extends RouteBuilder {
  //Split the content of the file into lines and the process it 
      @Override
      public void configure() throws Exception {
          from("file:C:/inputFolder").split().tokenize("\n").to("jms:queue:javainuse");
      }
  
  }
  

• EIP- Content Based Router
  The Content-Based Router inspects the content of a message and routes it to another channel based on the content of the message. Using such a router enables the message producer to send messages to a single channel and leave it to the Content-Based Router to inspect messages and route them to the proper destination. This alleviates the sending application from this task and avoids coupling the message producer to specific destination channels.
  
  
  

  package com.javainuse;
  
  import org.apache.camel.builder.RouteBuilder;
  
  public class SimpleRouteBuilder extends RouteBuilder {
  
      @Override
      public void configure() throws Exception {
          from("file:C:/inputFolder").split().tokenize("\n").to("direct:test");
          
  //Content Based routing- Route the message based on the token it contains.
          from("direct:test"). 
          choice().
          when(body().contains("javainuse1"))
          .to("jms:queue:javainuse1").
          when(body().contains("javainuse2"))
          .to("jms:queue:javainuse2")
          .when(body().contains("javainuse3"))
          .to("jms:queue:javainuse3").
          otherwise().
          to("jms:queue:otherwise");
         
      }
  
  }
  }
  

• EIP- Message Filter
  A Message Filter is a special form of a Content-Based Router. It examines the message content and passes the

message to another channel if the message content matches certain criteria. Otherwise, it discards the message.

package com.javainuse;

import org.apache.camel.builder.RouteBuilder;

public class SimpleRouteBuilder extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        from("file:C:/inputFolder").split().tokenize("\n").to("direct:test");
        
        //Message Filter is a type of Content Based routing. 
        //If condition satisfied perform a task else discard it.
        from("direct:test"). 
        filter(body().contains("javainuse1"))
        .to("jms:queue:javainuse1");
       
    }

}

Recipient List
A Content-Based Router allows us to route a message to the correct system based on message content. This process is transparent to the original sender in the sense that the originator simply sends the message to a channel, where the router picks it up and takes care of everything.

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:/inputFolder").split().tokenize("\n").to("direct:test");
        
//Recipient List- Dynamically set the recipients of the exchange 
         //by creating the queue name at runtime
        from("direct:test")
        .process(new Processor() {
            public void process(Exchange exchange) throws Exception {
               String recipient = exchange.getIn().getBody().toString();
               String recipientQueue="jms:queue:"+recipient;
               exchange.getIn().setHeader("queue", recipientQueue);
      }
      }).recipientList(header("queue"));
       
    }

}
   

Wire Tap
Wire Tap allows you to route messages to a separate location while they are being forwarded to the ultimate destination.

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:/inputFolder").split().tokenize("\n").to("direct:test1");
        
        from("direct:test1")
        //Wire Tap:Suppose get some error so send seperate copies of the message to 
        //DeadLetter queue and also to direct:test2 
        .wireTap("jms:queue:DeadLetterQueue")
        .to("direct:test2");
        
        from("direct:test2")
        .process(new Processor() {
            public void process(Exchange arg0) throws Exception {
              //Some logic here
            }
      });
    }
}

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