This document provides an overview of the Spring Integration framework. It discusses key concepts like channels, endpoints, routers, filters and transformers. It describes common integration scenarios like file transfer, database integration and messaging. The goals of Spring Integration are to provide a simple model for complex enterprise integration and facilitate asynchronous, message-driven behavior within Spring applications. An example demonstrates converting a message to uppercase using a service activator and channels.

1. Spring framework
Motto: Musíte rozbít vejce když chcete udělat omeletu
Spring framework training materials by Roman Pichlík is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
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2. Spring Integration
Integruju, integruješ, integurjeme
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3. Integration scenarios
• File transfer
• Shared database
• Remote Procedure Call
• Messaging
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4. Goals And Principles
• Provide a simple model for
implementing complex enterprise
integration solutions
• Facilitate asynchronous, message-
driven behavior within a Spring-
based application
• Promote intuitive, incremental
adoption for existing Spring users
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5. Channel
• Point-to-Point
• Publish-Subscribe
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PublishSubscribeChannel
QueueChannel
PriorityChannel
RendezvousChannel

6. Endpoints
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7. • Message Channels
• Message Endpoints
• Service Activator
• Channel Adapter
• Router
• Filter
• Transformer
• Splitter
• Aggregator
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• Resequencer

8. Router
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A Message Router is responsible for deciding what channel or channels should receive the Message next (if any). Typically the decision is based upon the Message's content and/or metadata available in the
Message Headers. A Message Router is often used as a dynamic alternative to a statically configured output channel on a Service Activator or other endpoint capable of sending reply Messages. Likewise, a
Message Router provides a proactive alternative to the reactive Message Filters used by multiple subscribers as described above.

9. Service activator
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The Service Activator invokes an operation on some service object to process the request Message, extracting the request Message's payload and converting if necessary (if the method does not expect a
Message-typed parameter). Whenever the service object's method returns a value, that return value will likewise be converted to a reply Message if necessary (if it's not already a Message). That reply Message
is sent to the output channel. If no output channel has been configured, then the reply will be sent to the channel specified in the Message's "return address" if available.

10. Channel adapter
An inbound "Channel Adapter" endpoint connects a source system to a MessageChannel
An outbound "Channel Adapter" endpoint connects a MessageChannel to a target system.
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A Channel Adapter is an endpoint that connects a Message Channel to some other system or transport. Channel Adapters may be either inbound or outbound. Typically, the Channel Adapter will do some
mapping between the Message and whatever object or resource is received-from or sent-to the other system (File, HTTP Request, JMS Message, etc). Depending on the transport, the Channel Adapter may also
populate or extract Message header values. Spring Integration provides a number of Channel Adapters, and they will be described in upcoming chapters.

11. Příklad
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12. <si:channel id="input" /> public class Convertor {
public String toUpper(String s) {
<si:channel id="output"> return s.toUpperCase();
<si:queue capacity="10" /> }
</si:channel> }
<si:service-activator input-channel="input"
output-channel="output" ref="convertor" method="toUpper" />
<bean id="convertor" class="cz.sweb.pichlik.Convertor"></bean>
ApplicationContext context = new ClassPathXmlApplicationContext("classpath:META-INF/applicationContext.xml");
MessageChannel input = (MessageChannel) context.getBean("input");
PollableChannel output = (PollableChannel) context.getBean("output");
input.send(new StringMessage("Spring Integration rocks"));
Message reply = output.receive();
System.out.println("received: " + reply);
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