Preface

The world is becoming more connected than ever. There are hundreds of APIs on the Cloud, and more are added every day. Integrating existing systems, creating new applications, which can communicate easily with other applications, is becoming part of the everyday job of developers. Mastering an integration framework like Apache Camel, that can connect to a variety of systems and do message orchestration using well-known Enterprise Integration Patterns, is essential for any software engineer.

What this book covers

Creating a Camel project (Simple) provides a high-level overview of Camel architecture, and demonstrates how to create a simple message driven application.

Routing messages to different destinations (Simple) explains the message structure in Camel, and how to use it for routing messages with a Content-Based Router pattern.

Using components (Simple) shows how Camel utilizes URLs to configure components, and connect to a variety of systems.

Connecting routes (Simple) covers Message Exchange Patterns in Camel, and connecting routes with other parts of the applications.

Removing unwanted messages (Simple) introduces Message Filter and Idempotent Consumer patterns along with the powerful Bean Binding feature.

Transforming messages (Intermediate) demonstrates a variety of ways in which message transformations happens in Camel applications.

Splitting a message into many (Intermediate) presents the Splitter pattern and how the Camel threading model works.

Aggregating multiple messages into one (Intermediate) shows the Aggregator pattern and its usage in other patterns, such as Scatter-Gather and Composed Message Processor.

Reorganizing messages (Intermediate) introduces three more patterns used for changing the message order and frequency: Resequencer, Throttler, and Delayer.

Multicasting messages (Intermediate) shows how to send a message to multiple recipients using Recipient List and Wire Tap patterns.

Error handling and monitoring (Advanced) explains the Dead Letter Channel pattern, and the different techniques used in Camel for monitoring and dealing with errors.

Testing the messaging applications (Advanced) presents the different tools provided by Camel for testing the routing logic.

What you need for this book

In order to run the examples accompanying this book, you will need Java 6 or higher, Apache Maven 2.2.1 or higher, and Apache Camel version 2.11 or higher.

Who this book is for

This book is intended for Java developers who are new to Apache Camel and message oriented applications. It shows how to do application integration using the industry standard Enterprise Integration Patterns.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "In the Java DSL, we create a route by extending RouteBuilder and overriding the configure method."

A block of code is set as follows:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-core</artifactId>
    <version>${camel-version}</version>
</dependency>

Note

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Tip

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