We are considering the option of defining our REST interfaces using Camel REST DSL, as we are already using Camel for message routing, integration patterns and more. It seems that REST DSL covers what a standard JAX-RS implementation can do, but I am not sure if this is 100% true. Additionally, exposing the REST interfaces through Camel has the the added value of transparently propagating all the HTTP request headers to the Camel message, which seems to be a nice feature.
Apart from the non-functional issues, like separating interface and implementation that JAX-RS can offer, which option would you choose? Any input would be much appreciated.
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Does CXF 3.1.x really uses Apache HttpComponents - HttpClient for http transport? Maven dependencies does not list "Apache HttpComponents" as dependency nor do I see any HttpClient class in the CXF jars? However CXF JIRA CXF-6704 discusses about it?
I need access to HttpClient in CXF for NTLM support per connection basis which CXF by default relies on Java 6+ Authenticator which is set per JVM.
CXF has a decoupled runtime layer. Mostly they start with cxf-rt-*.
In the case of transports, cxf-rt-transports-*.
Take a look at this. I believe that this is the HTTP Components transport runtime.
EDIT: I think this is for asynchronous transport - (looked at the pom after I posted this).
EDIT2: I did a little more research on this and found this documentation. It says that the async client can be used for synchronous calls by setting use.async.http.conduit bus property to true. This also specifically refers to NTLM authentication.
Could anybody explain how Apache Camel is able to behave as a routing and mediation engine on a JAXRS API?
As far I've being reading about I've not been able to figure out what's it for?
You can consider Apache Camel as a great integration framework. It doesn't provide functionality itself, but it makes easy to glue multiple services and protocols together.
Apache Camel can expose a REST endpoint using the CXFRS component. This means it listens for a REST call on certain endpoint (URL). On invocation it doesn't invoke the implementing bean (service) itself, but executes a defined mediation route (invoke a route with its Exchange object).
It is very useful when you need to integrate multiple services or translate the call to other protocols. You can implement a REST service by a bean itself and it's ok until the bean provides some functionality or data itself. For integration you often need more flexibility to integrate multiple sources and protocols. Then Apache Camel can be much more practical tool.
I am still struggling with undertsanding some of Camel's main features and limitations.
My objective is to implement a demo application that can migrate camel endpoints. To achieve this everyone suggested that I should use the camel load-balancer pattern with the failover construct.
To achieve this objective people have suggested Fuse and ActiveMQ. Some have even suggested JBoss, but I am lost.
I understand that Camel needs the an implementation of a JMS server. To achieve this I can use ActiveMQ - a free implementation of a JMS server.
However camel also provies the jms-component. What is this? Is this a client implementation of JMS? If so, should I not be using an ActiveMQ client for JMS? Could someone provide a working example?
With ActiveMQ and JMS understood I can then try to find out why people suggest Fuse. I want my implementation to be as simple as possible. Why do I need Fuse? The Camel+ActiveMQ combination has the load balancer pattern with the failover mechanism right?
I am lost in this sea of new technologies, if someone could give a direction I would be thankful.
Camel provides two components. The first is the jms component, which is a generic API for working against JMS servers. The other is the activemq component, which uses the activemq API for working with activemq message brokers. The activemq component is the default component within things like servicemix/fuse, using an internal broker (not a networked/external broker).
If you are connecting to activemq, you can use either the activemq component or the jms component. The jms component will not start up a broker automatically, you would need to do this yourself.
Fusesource == JBoss Fuse == Apache ServiceMix + some addons. For argument sake, i'm going to refer to all three of these as ServiceMix.
ServiceMix is an enterprise service bus, you can lookup the term on wikipedia if you're not familiar with the concept. It uses Apache Camel to define routes between your components, implementing a number of integration patterns as you so need. ServiceMix deploys by default with Apache CXF, for JAX-RS and JAX-WS services and Apache ActiveMQ, a JMS message broker. Using Camel, you can tell service mix that when a REST API is called, do a series of steps, each step decoupled from the one before it.
JBoss Fuse (the enterprisey, costs money edition) comes with some additional components around fail over. Some of these are present in servicemix (namely, you can run servicemix in a hot stand by mode, waiting for the primary to go down). The Camel load balancer pattern doesn't really mean anything around replication, except that a message coming from one endpoint can be delivered to any of a set of a N endpoints. http://camel.apache.org/load-balancer.html
On the flipside, take a look at ServiceMix's failover http://servicemix.apache.org/docs/4.4.x/users-guide/failover.html
I think based on your question you're referring to system failure failover (needing to work against a new instance), and not a Camel Loadbalancer component (which is likely where the confusion is coming from, on the community side and your side).
start by reading these...Camel In Action, ActiveMQ In Action
I am new to fuse esb,I have a requirement where I have two web applications which will be in different servers (applications will be in different Jboss servers and Fuse will be in another physical machine) and they need to communicate using REST protocol via the fuse esb,I know that I have to use camel for routing the incoming request from one application to the another application,can any please share some thoughts or any link where I can get some information.I am frankly clueless at the moment any help will be greatly appreciated.
Regards,
I bet you have some requirement of exposing the REST API inside FUSE to achieve loose coupling.
You could use CXFRS to expose your REST interface if you need to parse the datatypes sent to Java and maybe map them to something else.
Another, somewhat simpler, component is Restlet. It allows you to deal with most aspects of REST style interfaces, such as URI parsing.
Since REST is plain HTTP, in some cases you can come a long way using the servlet/http4 components, maybe to simply proxy or route HTTP requests.
In any case, read up on those components and come back with more specific questions, should you have any
Can anyone give me a sample source code where i can use restful jax-rs web service as an interface to message broker using active mq. The requirement is traffic comes to application through jax-rs webservice and the message is transferred to active mq which is processed asynchronously and the consumer on active mq inserts data into db. Can anyone please provide sample code, that would be great
The question is very fuzzy. There are multiple concerns to take into account when doing this kind of interfaces as jax-rs is a http interface (synchronous, non transcational, non persistent, non guaranteed delivery) while activemq (jms) is the other way around, asynchronous, transactional and persistent.
I suggest you take a look at Apache Camel which is a lightweight integration framework that works really good with ActiveMQ. It supports JAX-RS as well. There are multiple code examples over at the Camel website and connecting rest with activemq is rather easy given you have your case fully designed.