What is the difference between above two? Most of the documentation on getting started with camel has examples with CamelContext but I also see ModelCamelContext used in places. When should I use one versus other?
Refer to this link.
The basic difference is CamelContext is an SPI (Service Provider Interface) and ModelCamelContext is an API for the known implementations [DefaultCamelContext, OsgiCamelContext, SpringCamelContext etc..], So if you are writing your own CamelContext implementation you must implement CamelContext and if suppose you want to access some of modeling data of any of the known implementations of CamelContext like SpringCamelContext then you must use the ModelCamelContext reference.
Difference between SPI and API?
Related
I'm new in Apache Camel world and currently looking to understand how to use camel endpoints to Java interface methods. As per my requirement, I want to use an external service while the component(bean or transform or a process) is still processing the message. In Mule world - this is how it is implemented -
<component class="org.mule.examples.bindings.InvokerComponent">
<binding interface="org.mule.examples.bindings.HelloInterface"
method="sayHello">
<cxf:outbound-endpoint
address="http://myhost.com:81/services/HelloWeb?method=helloMethod"
synchronous="true"/>
</binding>
</component>
Here in this example - The binding causes the sayHello method in HelloInterface to call out to the external HelloWeb service when sayHello is called when InvokerComponent is in execution.
Currently, I'm reading about camel CXF-RS but not sure if this is way to implement this type of use case in Camel. Can anyone please help me or guide me to implement this? Any code example will be great. Thank you so much!!
It’s quite an old unanswered question so sharing some ideas. You can use aggregator EIP for this situation.
The Aggregator from the EIP patterns allows you to combine a number of messages together into a single message.
https://camel.apache.org/components/3.13.x/eips/aggregate-eip.html
How to use Aggregator EIP using Spring and Apache Camel?
https://youtu.be/IdGuGGVv51Q
I want to know what is Route-builders in Apache camel? And why is it used for?
I have a project where JMS and apache camel are used but i dont know what is routebuilder.
In advance: I am not 100% sure about the long answer, so please correct me if I am fundamentally wrong here!
Short:
The basic definition given by the official apache camel docu states:
The RouteBuilder is a base class which is derived from to create
routing rules using the DSL. Instances of RouteBuilder are then added
to the CamelContext.
Long:
Routebuilder is an abstract class. When implementing your own route, you usually extend from that RouteBuilder class (as the citation above already stated).
As a consequence you must implement the method configure() in which you implement the route (from()/.to()/.process() etc.)
I am pretty sure it is possible to implement a route without extending RouteBuilder, but then you would have to rebuild the framework given by apache camel. The whole syntax (from()/.to()/.process() etc.) for implementing routes is provided by extending Routebuilder class.
Apache Camel is a framework. In order to use the framework your "route class" must inherit from the base classes of the given framework. Otherwise you would not be able use the framework, which already offers a huge part of the implementation.
If Claus Ibsen answers your question, stick to his answer, he knows virtually everything about apache camel.
I searched in web but did not find any explanation that what is the exactly CamelContext? where and how to use ?
I gone through below links also but not satisfied with explanation.
https://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/CamelContext.html
https://dzone.com/articles/apache-camel-tutorial-eip
There are many comparision for CamelContext with others, but what I am looking for is the what is it? I want some conceptual explanation.
Please help me to understand this.
It's roughly an instance of a Camel environment, or at least it's a reference to it. Most apps would only have one CamelContext, but you can have several if needed. Looking at the referenced document, it shows how the context has a lifecycle.
In most cases, the context will start and stop along with the application.
After seeing the videos in YouTube, I knew about the Apache camel framework,
and from that I got the answer that camelcontext is nothing but context of the 'apache camel framework' framework.
As many framework have context like Spring have an applicationcontext, Ninja have a context, same the 'Apache camel framework' have a context and that is called 'camelcontext'.
So, it is the run-time system of Apache Camel (framework) and it connects its different concepts such as routes, components or endpoints.
Reference :
Basic Apache Camel Tutorial
i tried to have aspectj for camel processor, but it is not working. My pointcut is below:
#Around("execution(* org.apache.camel.processor.UnmarshalProcessor.*(..))")
Will it possible to do aspect for camel processor?? if yes, help.
Yes, you can if you put the library on the inpath in a compile-time weaving scenario, creating modified versions of the 3rd party class files and using them during runtime.
In a load-time weaving scenario you can also do it dynamically if the weaving agent is loaded before the Camel classes, which should usually be the case.
As a work-around you can change the pointcut type from execution() to call(), intercepting the callers in your own code rather than the callee in the 3rd party library.
So you have at least three options, all of which work with AspectJ (not in an "AOP lite" variant like Spring AOP though).
I am studying Apache Camel.
Could some one please explain the difference between a processor, component and endpoint with regard to Apache Camel.
A component allows you to talk with other systems. It allows you to send or receive messages and encapsulates the protocol to deal with another system. For e.g. jms-component allows to talk with JMS brokers.
An endpoint is nothing but the channel by which you send or receive a message through component e.g. "jms:queue:order" this defines a jms endpoint which is a queue from where your (jms) component will either consume or publish a message.
While a processor is piece of code which goes in between routes. There you write code to manipulate (transform/enrich/extract etc.) the message or have some integration logic.
For more details refer to camel's documentation
All whom are new to Apache Camel I suggest to read this article which explains really well what Camel is, and has an example to go along.
http://java.dzone.com/articles/open-source-integration-apache
Another great piece is chatper 1 of the Camel in Action book, which can be freely downloaded from here: http://www.manning.com/ibsen/Camel_ch01_update.pdf
Disclaimer: I am co-author of that book.
And there is this old by good tutorial that still applies today: http://camel.apache.org/tutorial-example-reportincident.html
And you can find more tutorials / examples on the Camel website
http://camel.apache.org/tutorials.html
http://camel.apache.org/examples.html
And there is also some links to 3rd party blogs/articles/videos about Camel, where you can find some great information:
http://camel.apache.org/articles.html