Introduction to Spring Integration

Introduction

The objective of this post to provide introduction to Spring Integration. Spring Integration is most popular messaging framework is being used day-to-day and extends the spring programming model to support the Enterprise Integration Patterns (EIP). It is based on pipe and filter design architecture.

Spring Integration framework build upon core spring framework and supports same kind of configuration style, XML, annotation and programming etc.

This framework consists of 3 components, that is

• Messages
• Channels
• Endpoints

How Spring Integration framework work?

This framework works on mechanism of sending and receiving lightweight messages. Here are the steps :-

1. Message builder create a message contain information called payload.
2. Then producer send message to a channel (represents pipe in "pipe and filter" architecture ) and consumer receive message from the channel.
3. Message channel may follow either point-to-point or publish-subscribe semantics like JMS.
4. Endpoint represents filter in "pipe and filter" architecture.
5. Endpoint perform some action based on payload, or could route the message to another endpoint to do the action.

First Spring Integration Program

Step.1: Install maven

Step.2: Install eclipse

Step.3: Download Spring integration jars

Step.4: Do the eclipse setup for new maven project

Step.5: Run SpringIntegrationMain program

Project Structure in Eclipse

spring-config.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"

      xmlns:integration="http://www.springframework.org/schema/integration"

      xmlns:beans="http://www.springframework.org/schema/beans"

      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://www.springframework.org/schema/integration

            http://www.springframework.org/schema/integration/spring-integration.xsd">

   <context:annotation-config /> 

   <context:component-scan base-package="com.manoja.brahma.learnings"/> 

    <integration:channel id="inputChannel"/> 

   <integration:service-activator input-channel="inputChannel" ref="springIntegrationService" method="greet" output-channel="outputChannel"/>

   <integration:channel id="outputChannel"/>    

 <integration:service-activator input-channel="outputChannel" ref="springIntegrationDisplay"/> 

</beans> 

SpringIntegrationMain.java

package com.manoja.brahma.learnings;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import org.springframework.integration.Message;

import org.springframework.integration.MessageChannel;

import org.springframework.integration.support.MessageBuilder;

/**

 * This main class creates input channel and sends Spring Integration greetings message to the channel

*

 * @author Manoja Brahma

 */

public class SpringIntegrationMain {

public static void main( String[] args ) {

  //Get the context instance

  final ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");

  // get the message channel reference from the application context

  final MessageChannel channel = context.getBean("inputChannel", MessageChannel.class);

  // create a message with the content "World" through MessageBuilder withPayLoad()

  final Message<String> message = MessageBuilder.withPayload("Spring Integration").build();

  // send the message to the inputChannel

  channel.send(message);

  }

}

SpringIntegrationService .java

package com.manoja.brahma.learnings;

import org.springframework.stereotype.Service;

/**

 * This service modify the original message and return the new message to the output channel

 *

 * @author Manoja Brahma

 */

@Service

public class SpringIntegrationService {

  public String greet(String name) {

    return "First " + name + " Program";

  }

}

SpringIntegrationDisplay .java

package com.manoja.brahma.learnings;

import org.springframework.integration.annotation.ServiceActivator;

import org.springframework.stereotype.Service;

/**

 * This service consume the message from the channel and print it on the console

 *

 * @author Manoja Brahma

 */

@Service

public class SpringIntegrationDisplay {

  @ServiceActivator

  public void display(String value){

    System.out.println(value);

  }

}

Thank you

Manoja Brahma