Overview of the Apache Camel

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In this blog, we are going to overview the Apache Camel. As, We have so many integration frameworks in the software market, open-sourced, and licensed. But, Let’s see Why the Apache Camel integration framework is one of the best open-source software.

Apache Camel

It is an open-source Java tool of Apache that permits you to quickly and simply transfer the data between two systems.

It is simple to use Domain-Specific Languages (DSLs) to wire EIPs and transports along Camel receives messages from some endpoint and sends them to a different one. The messages process or just routed to completely different endpoints depending on the transformation logic applied in the Camel.

It permits integration just by providing connectivity to a large form of transports and APIs.

For example, you can simply route JMS to JSON, JSON to JMS, HTTP to JMS, FTP to JMS, even HTTP to HTTP, and connectivity to Microservices.

Why Apache Camel?

Here are several most significant features of Apache Camel that you simply may notice helpful once coming up with Camel applications.

Apache Camel is a lightweight framework. It is deployed on various components of containers such as tomcat, ESBS, etc.
Apache Camel provides us with a large variety of components. These elements interact to make endpoints with which a system can interact with other external systems. There are over a hundred and fifty components provided by Apache Camel.
Components such as ActiveMQ, Kafka, Rest APIs, FTP, JMX, HTTP, etc. are provided by Apache Camel.
Apache Camel utilizes Message Exchange Patterns(MEP). Apache Camel exchange will hold any reasonable message. It supports a large variety of formats like XML, JSON, etc.
Camel provides many types of converters for marshaling and unmarshalling the message throughout the routing. Routes in an exceeding form of domain-specific languages (DSL).
The most common ones are:
Java DSL – A Java-based DSL using the fluent builder style.
Spring XML – A XML based mostly DSL in Spring XML files.
When using Spring XML we will create use of Spring support for options such as transaction Management, JPA, etc.
Camel supports pluggable languages to put in writing predicates in DSL.

Terminologies of Apache Camel

Now, Let’s now discuss the fundamental Camel terminology

Endpoint: The Endpoint is a channel through which the system will receive or send a message. Moreover, It refers to a web service URI, queue URI, file, email address, etc.
Message: The message contains information that’s being transferred to a route. Every message incorporates a unique identifier, created out of a body, headers, and attachments.
Exchange: Exchange is the container of a message, created once a message received by a consumer throughout the routing process. Exchange permits various styles of interaction between systems, it will define a unidirectional message or a request-response message.
Component: Component references find a component within an assembly. Apache component References provides a range of references that provide services for messaging, transmitting data, notifications, and a variety of different services that can not solely resolve simple messaging and data transfer but conjointly provide data security.
- Core components: Total 25 in 22 JAR artifacts. For Example, Bean, log, Class, REST API, Timer, XSLT, etc are few of them.
- Non-Core components: Total 320 in 247 JAR artifacts (1 deprecated). For Example, ActiveMQ, AMQP, atom, AWS, AWS Lambda, Kafka, AWS MQ, crypto, etc are few of them.
Route: The Route in Apache Camel is a collection of steps that Camel performs to consume and process a message. A Camel route begins with a client or customer and progresses through a series of endpoints and processors. Routes in Java are located within a RouteBuilder class.
Processor: A Processor is a straightforward Java interface that is used to add custom integration logic to a route. It contains a single process method used to perform custom business logic on a message received by a consumer.
CamelContext: CamelContext represents the Camel runtime system and it wires different concepts such as routes, components, or endpoints.

Apache Camel Architecture

Camel utilizes a Java-based Routing Domain Specific Language (DSL) or XML Configuration to configure routing and mediation rules that are added to a CamelContext to implement the assorted Enterprise Integration Patterns.

*Source / Curtesy : apache camel manual*

At a high-level camel, CamelContext contains a collection of component instances. A component may be a factory of Endpoint instances. You can configure tack component instances in Java code or an IoC container such as Spring, or they will be auto-discovered using URIs.

An endpoint could be a channel through which the system will receive or send a message. It will refer to a web service URI, queue URI, file, email address, etc

The Domain Specific Language (DSL) uses pluggable Languages to create an Expression or Predicate to form a very powerful telephone circuit, that is extensible to the most suitable language depending on needs. Most Languages additionally support Annotation-based Expression Language.