In theory, creating a queue in Artemis is pretty straightforward. If you're
on a client you can use:
- org.apache.activemq.artemis.api.core.client.ClientSession
If you're on the broker then you could use:
- org.apache.activemq.artemis.core.server.ServerSession (e.g. if you're
creating a queue on behalf of a client)
- org.apache.activemq.artemis.core.server.impl.ActiveMQServer (e.g. if
you're creating a queue for the broker's internal use or for a test)
In Artemis 1.0 there were a handful of methods on each of these classes to
create queues with different configurations. Here's the breakdown of the
number of overloaded methods:
- org.apache.activemq.artemis.api.core.client.ClientSession
- createQueue: 6
- createSharedQueue: 4
- createTemporaryQueue: 2
- org.apache.activemq.artemis.core.server.ServerSession
- createQueue: 1
- createSharedQueue: 1
- org.apache.activemq.artemis.core.server.impl.ActiveMQServer
- createQueue: 3
- createSharedQueue: 1
- deployQueue: 1
- updateQueue: 0
Here's a breakdown of those same methods in 2.11.0 (i.e. the latest
release):
- org.apache.activemq.artemis.api.core.client.ClientSession (over 200%
increase)
- createQueue: 21
- createSharedQueue: 6
- createTemporaryQueue: 10
- org.apache.activemq.artemis.core.server.ServerSession (700% increase)
- createQueue: 11
- createSharedQueue: 5
- org.apache.activemq.artemis.core.server.impl.ActiveMQServer (500%
increase)
- createQueue: 18
- createSharedQueue: 4
- deployQueue: 2
- updateQueue: 6
Almost every time a new queue parameter was added then a collection of
corresponding overloaded methods were added as well to support the new
parameter. As the number of parameters in these methods has increased the
usability has decreased. For example, if you wanted to create a queue with
all the default parameters but with a custom ring-size then you would have
to call a createQueue method with *26* parameters.
Furthermore, there are multiple places in the code-base where all the queue
configuration parameters are encapsulated:
- org.apache.activemq.artemis.api.core.QueueAttributes
- org.apache.activemq.artemis.core.server.QueueConfig
- org.apache.activemq.artemis.core.server.QueueConfig.Builder
- org.apache.activemq.artemis.core.config.CoreQueueConfiguration
When a new parameter is added then all of these objects need to be updated
as well.
In short, maintainability here is a bit of a nightmare.
I've sent a PR [1] to address these usability and maintainability issues.
The PR itself describes the solution(s) so I won't repeat that information
here.
There's no rush on merging this except that I think it should be merged
with plenty of time before 3.0 (whenever that will be) so users can migrate
from the deprecated methods before they are removed completely.
Justin
[1] https://github.com/apache/activemq-artemis/pull/3063
