List of Listings

Chapter 1. Meeting Camel

Listing 1.1. Routing files from one folder to another in plain Java

Listing 1.2. Routing files from one folder to another with Apache Camel

Listing 1.3. The Maven POM required to use Camel’s core library

Listing 1.4. Routing files from one folder to another with Apache Camel

Chapter 2. Routing with Camel

Listing 2.1. Polling for FTP messages and sending them to the incomingOrders queue

Listing 2.2. A Spring configuration that produces the same results as listing 2.1

Listing 2.3. A Spring DSL example that produces the same results as listing 2.1

Listing 2.4. A complete content-based router

Chapter 3. Transforming data with Camel

Listing 3.1. Using a Processor to translate from a custom format to CSV format

Listing 3.2. Using a bean to translate from a custom format to CSV format

Listing 3.3. Using pollEnrich to merge additional data with an existing message

Listing 3.4. Using XStream to transform a message into XML

Listing 3.5. Annotating a bean with JAXB so it can be transformed to and from XML

Listing 3.6. Using JAXB to serialize objects to and from XML

Listing 3.7. Model object annotated for CSV transformation

Listing 3.8. Using Bindy to transform a model object to CSV format

Listing 3.9. An HTTP service that returns order summaries rendered in JSON format

Listing 3.10. Configuring the CSV data format

Listing 3.11. Developing a custom data format that can reverse strings

Listing 3.12. A custom type converter to convert from byte[] to PurchaseOrder type

Chapter 4. Using beans with Camel

Listing 4.1. Using a Processor to invoke the hello method on the HelloBean

Listing 4.2. Setting up Spring to use a Camel route that uses the HelloBean

Listing 4.3. A Camel route using a Processor to invoke HelloBean

Listing 4.4. Using SimpleRegistry to unit test a Camel route

Listing 4.5. A service that stamps an order ID on an XML document

Chapter 5. Error handling

Listing 5.1. Using two error handlers at different scopes

Listing 5.2. Using error handling with Spring XML

Listing 5.3. Using doTry ... doCatch with Camel routing

Listing 5.4. Using onException in context scope

Listing 5.5. Spring XML revision of listing 5.4

Listing 5.6. Using a processor to create a failure response to be returned to the caller

Listing 5.7. Using continued to ignore ValidationExceptions

Listing 5.8. Route using error handling with failover to FTP

Listing 5.9. A helper to determine whether an HTTP error 500 occurred

Listing 5.10. Skeleton code to illustrate principle of using retryWhile

Chapter 6. Testing with Camel

Listing 6.1. A first unit test using the Camel Test Kit

Listing 6.2. A Spring-based version of the route in listing 6.1 (firststep.xml)

Listing 6.3. A first unit test using Spring XML routes

Listing 6.4. A reusable unit test for the test and production environments

Listing 6.5. Using the Camel Properties component with the Java DSL

Listing 6.6. Using MockEndpoint in unit testing

Listing 6.7. Using expressions with MockEndpoint to set expectations

Listing 6.8. Using a custom expression to detect gaps in message ordering

Listing 6.9. Simulating a real component by using a mock endpoint

Listing 6.10. Route using error handling with a failover to FTP

Listing 6.11. Simulating an error by throwing an exception from the mock endpoint

Chapter 7. Understanding components

Listing 7.1. Topics allow multiple receivers to get a copy of the message

Listing 7.2. The CXF endpoint bean format

Listing 7.3. The WSDL for an order service

Listing 7.4. Using CXF’s wsdl2java tool

Listing 7.5. CXF endpoint configuration in camel-cxf.xml

Listing 7.6. Web-enabled route configuration

Listing 7.7. The decoder for the welder sensor

Listing 7.8. A bean that converts an incoming order to an SQL statement

Listing 7.9. An annotated POJO representing an incoming order

Listing 7.10. Hooking up the Camel JPA component to OpenJPA

Listing 7.11. Configuring the ORM tool with the persistence.xml file

Listing 7.12. A topic allows multiple receivers to get a copy of the message

Chapter 8. Enterprise integration patterns

Listing 8.1. AggregationStrategy for merging messages together

Listing 8.2. Using HawtDB with Aggregator in Java DSL

Listing 8.3. Using HawtDB with Aggregator in Spring XML

Listing 8.4. A basic example of the Splitter EIP

Listing 8.5. Splitting big files using streaming mode

Listing 8.6. Splitting big files using streaming mode in Spring XML

Listing 8.7. Combining split messages back into a single outgoing message

Listing 8.8. Handling an exception by ignoring it

Listing 8.9. Propagating back an exception

Listing 8.10. Java bean deciding where the message should be routed next

Listing 8.11. Custom load balancer

Chapter 9. Using transactions

Listing 9.1. Using a bean to map from XML to SQL

Listing 9.2. XML configuration for the Camel route, JMS broker, and database

Listing 9.3. Simulating a connection failure that causes lost messages

Listing 9.4. XML configuration using Spring transactions

Listing 9.5. Testing a simulated rollback on the first try and a commit on the second try

Listing 9.6. Unit test with a transacted route calling a non-transacted route

Listing 9.7. Two transacted routes

Listing 9.8. Using onCompletion as a transactional rollback

Chapter 10. Concurrency and scalability

Listing 10.1. Rider Auto Parts application for updating inventory

Listing 10.2. Rider Auto Parts inventory-update application using SEDA

Listing 10.3. Using ExecutorServiceStrategy to create a thread pool

Listing 10.4. Asynchronous task execution using the Java API

Listing 10.5. Using a callback to gather replies asynchronously

Listing 10.6. ErpProducer using the asynchronous processing model

Chapter 11. Developing Camel projects

Listing 11.1. Layout of the project created by camel-archetype-java

Listing 11.2. Layout of a project created by camel-archetype-component

Listing 11.3. Custom Camel endpoint—MyEndpoint

Listing 11.4. Custom Camel producer—MyProducer

Listing 11.5. Custom Camel consumer—MyConsumer

Listing 11.6. A custom interceptor

Listing 11.7. Configuring compilation of both Java and Scala sources

Chapter 12. Management and monitoring

Listing 12.1. A custom event notifier publishes failure events to a central log database

Listing 12.2. Management-enabling a custom endpoint

Chapter 13. Running and deploying Camel

Listing 13.1. Starting routes in a specific order

Listing 13.2. Spring XML version of listing 13.1

Listing 13.3. After a file has been processed, the route is stopped

Listing 13.4. A RoutePolicy that flips two routes being active at runtime

Listing 13.5. Bootstrapping Camel in your Java application

Listing 13.6. The Spring applicationContext.xml file with Camel embedded

Listing 13.7. The web.xml file with CXFServlet to tap into Apache Tomcat

Listing 13.8. Setting up the Camel CXF component to tap into Apache Tomcat

Chapter 14. Bean routing and remoting

Listing 14.1. A Java class that can update the inventory database

Listing 14.2. InventoryUpdater class connected to JMS queue by @Consume

Listing 14.3. Using the @Produce annotation to set up a ProducerTemplate

Listing 14.4. Using the @Produce annotation to set up a producer on an interface

Listing 14.5. Simulating Rider Auto Parts

Listing 14.6. Spring XML setting up Camel

Listing 14.7. Server with ActiveMQ broker

Appendix A. Simple, the expression language

Listing A.1. Using the Simple language from custom Java code

Appendix B. Expressions and predicates

Listing B.1. Implementing a custom expression

Listing B.2. Implementing custom expression by extending ExpressionAdapter

Listing B.3. Implementing a custom predicate

Appendix C. The producer and consumer templates

Listing C.1. Using a ProducerTemplate to send a message to a JMS topic

Listing C.2. Using a ProducerTemplate to get a reply from an endpoint

Listing C.3. Declaring reusable producer and consumer templates

Listing C.4. Using the ConsumerTemplate to poll a JMS queue

Appendix E. Akka and Camel

Listing E.1. Actor as consumer receiving messages from a SEDA endpoint

Listing E.2. Actor acting as consumer which sends back replies to sender

Listing E.3. An actor sending back XML messages as reply to sender

Listing E.4. An actor as a producer sending messages to the defined HTTP endpoint

Listing E.5. Spring XML file setting up Akka and Camel

Listing E.6. Camel route sending message to Akka actor

Listing E.7. Akka consumer and producer example