Yeah, that makes it clearer.
Some remarks:
1) How does the channel work? Does it work only within the CamelContext
(like SEDA), in the whole virtual machine (like VM) or can it be used
distributed (like JMS)?
2) Wouldn't be easier if you separate it in two components: "publish" and
"subscribe" and then do something like:
from("direct:a")
.to("publish:mychannel");
from("subcribe:mychannel?id=1&priority=1&predicate=<text predicate>")
.to("someUri");
from("subcribe:mychannel?id=2&priority=2predicate=<text predicate>")
.to("someUri");
from("subcribe:mychannel?id=3&priority=3&predicate=<text predicate>")
.to("someUri");
3) In the documentation maybe could to add an example with subscribe while
using different expression languages/predicates.
Raymond
On Sat, Nov 5, 2022 at 7:01 PM Steve973 <steve...@gmail.com> wrote:
> Hi, Raymond, and thank you so much for your response! I appreciate it, and
> I appreciate that you included those two links that I probably should have
> included.
>
> I will do my best to answer your questions, but since I am not the best
> teacher, please let me know where I need to explain better:
>
> 1. The best way I would generally describe the use case for this EIP
> component is when you want dynamic orchestration between modules of your
> system:
> a. You have services that come and go over time, possibly because your
> system watches for something to occur, and then it spins up services
> to handle whatever follows. This allows them to plug into routing,
> perform
> their tasks, and then unplug from routing when they are going to stop
> and
> go away.
> b. You have a way to programmatically enable and disable features of
> your system. Enable them, and they subscribe for routing. Disable
> them,
> and they unsubscribe.
> c. You want a way to decentralize your routing logic and keep
> module-specific routing in the applicable module. The router does not
> have
> to know the system's list of commands, or how to handle any of them
> prior
> to runtime.
> 2. Your understanding of the channels is correct. This allows for
> logical separation of routing. One channel has one set of subscribers
> that
> is separate from any other channel that has its own (separate) set of
> subscribers.
> 3. You can use an object for subscribing or unsubscribing, and you can
> also use the URI (see
>
> https://camel.apache.org/components/3.18.x/dynamic-router-component.html#_method_2_uri_only
> to see what I mean). Use of the component in a route is as simple as
> from("<some uri>").to("dynamic-router:<channel name>") so, at least in
> that
> part, you don't have to worry about any java code, since using the
> dynamic
> router component is just like using any other camel component. When you
> are subscribing/unsubscribing is where using code might apply, to create
> the subscription message and then send it, for example, by a producer
> template.
>
> Please let me know if this helps. I am always open to expanding its
> usefulness, or simplifying its use. So, if you have any suggestions, I
> would be happy to see how I could get it integrated into the component.
>
> Thanks again,
> Steve
>
> On Sat, Nov 5, 2022 at 11:44 AM ski n <raymondmees...@gmail.com> wrote:
>
> > For those interested. Here are some more resources:
> >
> > Background:
> >
> > https://camel.apache.org/blog/2022/01/dynamic-router-eip-component/
> >
> > Documentation:
> >
> > https://camel.apache.org/components/3.18.x/dynamic-router-component.html
> >
> > -------------------
> >
> > For me, reading through the documentation, it seems like a powerful
> > component. However, there are some things I am failing to grasp:
> >
> > 1. What are the use cases this can be used for. And with kind of use
> cases
> > I mean business use cases explained in simple terms for end-users.
> > 2. As I understand it, the dynamic router provides 'topics' similar to
> > Kafka topics or JMS topics, but then build into Camel. Is this correct?
> > 3. In the documentation examples I see a lot of plain Java code. Things
> > like unsubscribing:
> >
> > // Send message to the Dynamic Router "billing" channel// to
> > unsubscribe from billing messagesDynamicRouterControlMessage
> > unsubscribeMsg = new UnsubscribeMessageBuilder()
> > .id("billingSubscription")
> > .channel("billing")
> > .build();
> > template.sendBody("dynamic-router:control", unsubscribeMsg);
> >
> > I try to use the Route DSL's as much as possible. (especially XML and
> YAML,
> > because they are easily to manipulate). How can I use the component
> within
> > regular routes without things like Predicates and other Java code?
> >
> > Kind regards,
> >
> > Raymond
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > On Sat, Nov 5, 2022 at 4:06 PM Steve973 <steve...@gmail.com> wrote:
> >
> > > Hello. I introduced a Dynamic Router EIP component in 3.15 because I
> had
> > > uses for a dynamic router that was a bit different than what the core
> > > component offers. I would like some feedback about what features to
> > > potentially add that would make it even more useful. First, just in
> case
> > > you are not familiar with its capabilities, I will describe how I am
> > using
> > > it in a software system that I am building at work, which exercises it
> > > fairly well. We have a little fewer than 10 spring boot modules that
> > > handle specific tasks of the system. One of the modules is a "routing
> > > engine" that is mostly a wrapper for Camel, along with some
> > > business-logic-specific integration code. This is where I instantiate
> > the
> > > Dynamic Router component, and create a JMS route that can feed it
> > > subscriber messages. The other modules register their subscriptions
> with
> > > the dynamic router by sending messages over JMS to the router. These
> > > messages contain a predicate that allows the dynamic router to evaluate
> > > messages that pass through it to determine one, or more, recipients.
> > With
> > > their subscription messages, they also include a destination URI for
> > > applicable messages to be routed to. This allows for a somewhat
> advanced
> > > version of the command pattern in my system.
> > >
> > > Can any of you think of what this is missing? My first implementation
> > used
> > > a list for keeping track of subscribers, but that allowed a module to
> > > register its commands multiple times. So, that has been changed to a
> map
> > > that maps by subscriber ID. The other thing, and I have not developed
> a
> > > solution for this, but in the event of an error, the "routing table" of
> > > routes and endpoints is not available that I know of. I am not sure
> how
> > to
> > > handle that, or if there is something built into Camel that might
> > > facilitate that type of tracing/debugging information, of it I might
> need
> > > to keep track of it in a table within the component.
> > >
> > > Anyway, this is already long enough, and I don't want to bore you with
> > too
> > > many details. If you have time, please provide some feedback, and I
> will
> > > get more features into the Dynamic Router EIP.
> > >
> > > Thanks,
> > > Steve
> > >
> >
>
