NOT CONFIDENTIAL - TELL EVERYONE

EAI Patterns with Spring IntegrationOliver Gierke, EngineerSpringSource, a division of VMware

About Me

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Oliver Gierke

SpringSource Spring Data

ogierke@vmware.com

www.olivergierke.deolivergierke

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Agenda

• What is EAI?

• Messaging

• Pipes and Filters

• EAI Patterns

• Spring Integration 2.0

• Spring Integration 2.1

What is EAI?

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(Don’t try this at home)

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A Better Solution: Spring Integration

• Spring Integration Brings EAI To Your Application

• not the other way ‘round

• Provides the best support for “Enterprise Integration Patterns”

• patterns are built right into the API

• Heavy Emphasis on “channels”

• other solutions omit this key concept

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Messaging

• Integrates two different systems

• Different parties need to share the same data contract

• Not the same service contract

• Fault tolerant, since requests are enqueued and delivered as possible

• AMQP, JMS provide powerful, robust options

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Messaging

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Data Processing with Spring: Integration

• Messaging works by decoupling systems

• The Spring messaging machinery lets you react to messages, declaratively

• Spring Integration takes this approach to the next level

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?

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Events

Data Processing with Spring: Messaging

• JMS

• Standard in the Java space

• Lots of open source options

• Provided with Java EE application servers

• Spring JMS

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Data Processing with Spring: Messaging

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Java producers

C

C

C

P

P

queue

Java consumers

queue

Message broker

• Sending JMS Messages

• Inject an instance of Spring's JmsTemplate.

• Provide the JMS ConnectionFactory in the JmsTemplate bean definition.

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JMS

@Component public class MessageSender {

@Autowired private JmsTemplate jmsTemplate;

public void send(String message) { this.jmsTemplate.convertAndSend("example.queue", message); }}

@Bean public ConnnectionFactory cf (){ return new CachingConnectionFactory(...); }@Bean public JmsTemplate template(){ return new JmsTemplate(this.cf()) ;}

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JMS

Data Processing with Spring: Messaging

• AMQP

• Real standard

• A product of the the companies with the most mission critical requirements

• Spring AMQP

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Data Processing with Spring: Messaging

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AMQP producers

C

C

C

P queue

AMQP consumers

queue

Message broker

X

P X

exchanges

• Sending AMQP Messages

• Use AmqpTemplate instead of JmsTemplate (accepts exchange and routingKey).

• Nothing changes on the listener side (just a POJO).

@Component public class MessageSender {

@Autowired private AmqpTemplate amqpTemplate;

public void send(String message) { this.amqpTemplate.convertAndSend( "myExchange", "some.routing.key", message); }}

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AMQP

• HTTP Messaging (Request/Reply)

• Use RestTemplate, passing URI to methods based on HTTP methods

• Configure HttpMessageConverters if out-of-the-box support is insufficient

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HTTP

public class HttpClient {

private final String uri = “http://localhost/demo/{name}”; private final RestTemplate template = new RestTemplate();

public String getResource(String name) { this.template.getForObject(uri, String.class, name); }

public URI postResource(String name, Object resource) { this.template.postForLocation(uri, resource, name); }}

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HTTP

• Sending Mail Messages

• Create a SimpleMailMessage instance (or JavaMail MimeMessage).

• Use MailSender (or JavaMailSender) configured with host/user/password, etc.

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Mail

@Component public class MailClient {

@Autowired private MailSender mailSender;

public void send(String subject, String to, String text) { SimpleMailMessage message = new SimpleMailMessage(); message.setSubject(subject); message.setTo(to); message.setText(text); this.mailSender.send(message); }}

Pipes and Filters

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Pipes and Filters

• Messaging

• Payload can be any object

• Header values are stored in a Map

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• Message and Headers

Pipes and Filters

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public interface Message<T> { MessageHeaders getHeaders(); T getPayload();}

Message<String> m1 = MessageBuilder.withPayload(“foo”) .setHeader(“itemId”, 123).build();Message<String> m2 = MessageBuilder.fromMessage(m1) .setHeader(“itemId”, 456).build();

MessageHeaders headers = message.getHeaders();long timestamp = headers.getTimestamp();String value = headers.get(“someKey”, String.class);

• Message channel

• Decouples Producers from Consumers

• Provides extension point for interceptors

•May be Point-to-Point

•Or Publish/Subscribe

Pipes and Filters

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Pipes and Filters

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<channel id="sync-p2p"/><channel id="async-p2p"> <dispatcher task-executor="someThreadPool" /></channel><channel id="async-buffering-p2p"> <queue capacity="50" /></channel>

<publish-subscribe-channel id="sync-pubsub" />

<publish-subscribe-channel id="async-pubsub" task-executor="someThreadPool" />

• Message channel Types

Pipes and Filters

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• Sending Messages

public interface MessageChannel { boolean send(Message<?> message); boolean send(Message<?> message, long timeout);}

MessagingTemplate template = new MessagingTemplate();template.send(someChannel, message);template.send(“fooChannel”, message);template.convertAndSend(someChannel, “hello”);template.convertAndSend(“fooChannel”, someObject);template.setSendTimeout(5000);template.setDefaultChannel(someChannel);template.convertAndSend(someObject);

Pipes and Filters

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• Receiving Messages

• Inversion of Control

• Endpoints delegate to Spring-managed objects

• Framework handles message reception and method invocation (including conversion)

• Similar but more abstract than Spring JMS

• Clean separation of Code and Configuration

<service-activator input-channel="requests" ref="loanBroker" method="processRequest" output-channel="quotes"/>

@Component public class LoanBroaker { public Message<Quote> processRequest( Message<Loan> loan) { }}

„Hello World“

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• Message Endpoint

• Producers send Messages to a MessageChannel

• Depending on their type, MessageChannels may have PollingConsumers

• Or Event-Driven Consumers

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Pipes and Filters

Enterprise Integration Patterns

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Message Endpoint Types

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• Transformer

• Convert payload or modify headers

• Filter

• Discard messages based on boolean evaluation

• Router

• Determine next channel based on content

• Splitter

• Generate multiple messages from one

• Aggregator

• Assemble a single message from multiple

Filtering and Routing

• Filter returns a boolean

• Router returns a channel name (or map key)

• Other routers included out of the box:

• recipient-list

• payload-type

• header-value,

• xpath, ...

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<filter input-channel="customers" ref="customerRegistry" method="isVip" output-channel="vips" discard-channel="nonVips"/>

<router input-channel="customers" ref="customerRegistry" method="getStatus"> <mapping value="1" channel="platinum"/></router>

OddEven

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• Splitter returns a Collection or Array

• Aggregator accepts a Collection or Array

• Default Splitter and Aggregator require no ref/method

• Aggregator also has ReleaseStrategy and CorrelationStrategy

Splitting and Aggregating

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<splitter input-channel="orders" ref="orderRepository" method="getLineItems" output-channel="lineItems"/>

<aggregator input-channel="processedItems" ref="orderRepository" method="generateConfirmation" output-channel="confirmations"/>

Annotation Support

• Alternative to XML

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@ServiceActivator(inputChannel=“accounts”)public void createAccount(Account account) {…}

@Filter(inputChannel=“customers”, outputChannel=“vips”)public boolean isVip(Customer customer) {…}

@Splitter(inputChannel=“orders”, outputChannel=“lineItems”)public List<LineItem> getLineItems(Order order) {…}

Expression Language Support

• Alternative option for ref/method in endpoints

• Mapping between Messages and Methods

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<filter input-channel="customers" expression="payload.vip" output-channel="vips" discard-channel="nonVips"/>

public void createAccount( @Payload("firstName") String firstName, @Payload("lastName") String lastName, @Header("userInfo.account.id") String accountId) { …}

Book orders

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Channel Adapters and Messaging Gateways

• Many, many Adapters

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• HTTP (REST)

• WS (SOAP/POX)

• Mail (POP3/IMAP/SMTP)

• JDBC

• XMPP(S)

• Twitter

• Spring Events

• RSS/ATOM

• JMS

• AMQP

• TCP

• UDP

• File

• FTP(S)

• SFTP

• RMI

• Activiti BPMN 2

• MongoDB

• Redis

• Native File System Adapters

• SMPP(-S) (SMS gateways)

Feed

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Channel Adapters (one-way)

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<file:inbound-channel-adapter channel="fromFile" directory="${java.io.tmpdir}/input" filename-pattern="[a-z]+.txt"> <si:poller fixed-delay="5000" /></file:inbound-channel-adapter>

<jms:outbound-channel-adapter channel="toJms" destination="exampleQueue"/>

Gateways (request-reply)

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<http:outbound-gateway request-channel="httpRequests" url="http://trafficexample.org/{zipCode}"> <http:uri-variable name="zipCode" expression="payload.address.zip" /></http:outbound-gateway>

<ws:outbound-gateway request-channel="weatherRequests" uri="http://weatherexample.org" marshaller="jaxb2Marshaller" />

Spring Integration 2.0

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Major Themes

• Spring 3.0 support

• JDK 5 Support

• New Message Stores

• New Adapters

• Misc.

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Spring 3.0

• ConversionService

• Spring Integration takes advantage of a configured conversion service whenever it wants to perform certain conversions, from a certain primitives to complex objects in message parameters, for example.

• default Spring Integration conversion service bean ID: integrationConversionService

• must implement org.springframework.core.convert.converter.Converter

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<int:converter> <bean class="….MyConverterImplementation" /> </int:converter>

Spring 3.0

• Spring Expression Language

• through XML or Java

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<int:recipient-list-router id="customRouter" input-channel="routingChannel"> <int:recipient channel="channel1" selector-expression="payload.equals('foo')"/> <int:recipient channel="channel2" selector-expression="headers.contains('bar')"/></int:recipient-list-router>

<int:router input-channel="inChannel" expression="payload + 'Channel'"/>

<filter input-channel="input" expression="payload.equals('nonsense')"/>

Spring 3.0

• Spring Expression Language

• through XML or Java

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<int:transformer input-channel="inChannel" output-channel="outChannel" expression="payload.toUpperCase() + '- [' + T(java.lang.System).currentTimeMillis() + ']'" />

<filter input-channel="input" expression="payload.matches( #{filterPatterns.nonsensePattern})" />

Spring Integration 2.0

• New Adapters

• Drastically improved file system support

• JDBC inbound and outbound adapters

• RSS / ATOM

• Twitter

• XMPP

• TCP/

• Misc

• new JMS channel

• revised HTTP support

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Spring Integration 2.1

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Spring Integration 2.0

• Spring 3.1 support

• JDK 7 support

• Conversations

• New message stores

• New adapters

• AMQP / Redis / SMPP / Gemfire

• Misc

• Activiti

• Flex 1.5 / Comet

• Feedback

• What‘s valuable to you?

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Productivity boosters: STS Visual Editor

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Productivity Boosters: Forthcoming

• Productivity boosters

• STS template project

• Spring Roo addon

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Links

• Spring Framework Documentation

• http://static.springsource.org/spring/docs/3.0.x

• Spring Integration Sandbox

• git.springsource.org/spring-integration/sandbox

• Spring Integration

• http://www.springsource.org/spring-integration

• Enterprise Integration Patterns

• http://enterpriseintegrationpatterns.com

• Sample Code

• http://git.springsource.org/spring-integration/samples

• Getting Started with Spring Integration

• http://blog.springsource.com/category/green-beans/

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Credits

• Slides

• Mark Fisher, Josh Long, Adam Fitzgerald, Oliver Gierke

• Demos

• Spring Integration team

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