- Apache Camel Developer's Cookbook
- Table of Contents
- Apache Camel Developer's Cookbook
- Credits
- About the Authors
- Acknowledgments
- About the Reviewers
- www.PacktPub.com
- Preface
- 1. Structuring Routes
- Introduction
- Using Camel in a Java application
- Embedding Camel in a Spring application
- Using Camel components
- Reusing routing logic by connecting routes
- Asynchronously connecting routes
- Spanning Camel contexts within a single Java process
- Using external properties in Camel routes
- Reusing endpoints
- Reusing routing logic through template routes
- Controlling route startup and shutdown
- 2. Message Routing
- Introduction
- Content Based Routing
- Filtering out unwanted messages
- Wire Tap – sending a copy of the message elsewhere
- Multicast – routing the same message to many endpoints
- Recipient List – routing a message to a list of endpoints
- Throttler – restricting the number of messages flowing to an endpoint
- Request-response route sending a one-way message
- One-way route waiting on a request-response endpoint
- Dynamic Routing – making routing decisions at runtime
- Load balancing across a number of endpoints
- Routing Slip – routing a message to a fixed list of endpoints
- 3. Routing to Your Code
- 4. Transformation
- Introduction
- Transforming using a Simple Expression
- Transforming inline with XQuery
- Transforming with XSLT
- Transforming from Java to XML with JAXB
- Transforming from Java to JSON
- Transforming from XML to JSON
- Parsing comma-separated values (CSV)
- Enriching your content with some help from other endpoints
- Normalizing messages into a common XML format
- 5. Splitting and Aggregating
- Introduction
- Splitting a message into fragments
- Splitting XML messages
- Processing split messages in parallel
- Aggregating related messages
- Aggregating with timeouts
- Aggregating with intervals
- Processing aggregated messages in parallel
- Splitting a message, and processing and gathering responses
- Splitting messages and re-aggregating them using different criteria
- 6. Parallel Processing
- 7. Error Handling and Compensation
- Introduction
- Logging errors
- Dead Letter Channel – handling errors later
- Retrying an operation
- Conditional retry
- Customizing each redelivery attempt
- Catching exceptions
- Marking exceptions as handled
- Fine-grained error handling using doTry…doCatch
- Defining completion actions
- Defining completion actions dynamically
- 8. Transactions and Idempotency
- Introduction
- Preventing duplicate invocation of routing logic
- Transactional file consumption
- Using transactions with a database
- Limiting the scope of a transaction
- Rolling back a transaction
- Using transactions with messaging
- Idempotency inside transactions
- Setting up XA transactions over multiple transactional resources
- 9. Testing
- Introduction
- Testing routes defined in Java
- Using mock endpoints to verify routing logic
- Replying from mock endpoints
- Testing routes defined in Spring
- Testing routes defined in OSGi Blueprint
- Auto-mocking of endpoints
- Validating route behavior under heavy load
- Unit testing processors and Bean Bindings
- Testing routes with fixed endpoints using AOP
- Testing routes with fixed endpoints using conditional events
- 10. Monitoring and Debugging
- Introduction
- Logging meaningful steps within your route
- Debugging using logging
- Throughput logging
- Enabling step-by-step tracing in code
- Disabling JMX
- Configuring JMX
- Naming your routes to make it easier to monitor
- Adding JMX attributes and operations
- Monitoring other systems using the Camel JMX Component
- Setting breakpoints in your routes
- 11. Security
- 12. Web Services
- Index
Scott Cranton is an open source software contributor and evangelist. He has been working with Apache Camel since the release of version 1.5 almost 5 years ago, and has over 20 years of commercial experience in middleware software as a developer, architect, and consultant. During his time at FuseSource, and now Red Hat, he has worked closely with many core committers for Apache Camel, ActiveMQ, ServiceMix, Karaf, and CXF. He has also helped many companies successfully create and deploy large and complex integration and messaging systems using Camel and other open source projects.
He divides his professional time between hacking code, delivering webinars on using Camel and open source, and helping companies to learn how to use Camel to solve their integration problems.
I want to thank my amazing wife, Mary Elizabeth, for putting up with me these many years, and always answering the phone when I'd call late at night from the office while I've got a compile going. This book would not have been possible without her always being there for me no matter what. To my three wonderful children, Gilbert, Eliza, and Lucy, who always make me smile especially during crazy weekend writing sessions when they'd want me to take a break, "… but Dad, it's the weekend…" I love you all!
Jakub Korab is a consulting software engineer specializing in integration and messaging. With a formal background in software engineering and distributed systems, in the 14 years that he has worked in software across the telecoms, financial services, and banking industries, he naturally gravitated from web development towards systems integration. When he discovered Apache Camel, it became apparent to him how much time and effort it could have saved him in the past compared to writing bespoke integration code, and he has not looked back since.
Over the years, working as a consultant, he has helped dozens of clients build scalable, fault-tolerant, and performant systems integrations. He currently runs his own specialist consultancy, Ameliant, which focuses on systems integration and messaging using a stack of integration products from the Apache Software Foundation, of which Camel is a corner stone.
When not gluing systems together, you will find him spending time with his young family, and far too infrequently kitesurfing or skiing—neither of which he gets much chance to do in his adopted home, London.
The writing of this book has taken place against the background of starting a new company, a huge amount of work travel, a quickly growing baby, house move, and hundreds of little distractions that get in the way of sitting down in what is left of the day to put pen to paper. It could never have happened without the love, support, and understanding of my wife, Anne-Marie. It has been a team effort. Thank you.
Also to my little girl, Alex, for helping me keep it all in perspective.
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