When initially developed the expectation was that no more producers would keep connecting but in a scenario like this
the consumers could actually give up and things will just accumulate on the server.
We should cleanup these upon disconnect.
This commit does the following:
- Replaces non-inclusive terms (e.g. master, slave, etc.) in the
source, docs, & configuration.
- Supports previous configuration elements, but logs when old elements
are used.
- Provides migration documentation.
- Updates XSD with new config elements and simplifies by combining some
overlapping complexTypes.
- Removes ambiguous "live" language that's used with regard to high
availability.
- Standardizes use of "primary," "backup," "active," & "passive" as
nomenclature to describe both configuration & runtime state for high
availability.
As I worked through implementing a more generic JSON marshaller, I tried using reflection through BeanUtils and other ways
however the endresult was always worse as there were a few caveats that were not as easy to accomplish.
For that reason I went to a declarative appraoch where I define a meta-data object on AddressSettings and AddressSettingsInfo and
reuse the metadata in a few other places.
Durable subscrption state is part of the MQTT specification which has
not been supported until now. This functionality is implemented via an
internal last-value queue. When an MQTT client creates, updates, or
adds a subscription a message using the client-ID as the last-value is
sent to the internal queue. When the broker restarts this data is read
from the queue and populates the in-memory MQTT data-structures.
Therefore subscribers can reconnect and resume their session's
subscriptions without have to manually resubscribe.
MQTT state is now managed centrally per-broker rather than in the
MQTTProtocolManager since there is one instance of MQTTProtocolManager
for each acceptor allowing MQTT connections. Managing state per acceptor
would allow odd behavior with clients connecting to different acceptors
with the same client ID.
The subscriptions are serialized as raw bytes with a "version" byte for
potential future use, but I intentionally avoided adding complex
scaffolding to support multiple versions. We can add that complexity
later if necessary.
Some tests needed to be changed since instantiating an MQTT protocol
manager now creates an internal queue. A handful of tests assume that no
queues will exist other than the ones they create themselves. I updated
the main test super-class so that an MQTT protocol manager is not
automatically instantiated when configuring a broker for in-vm support.
This commit contains the following changes:
- eliminate used, undeclared dependencies
- eliminate unused, declared dependencies
- fix scope for test dependencies
- eliminate org.hamcrest completely as its use involved deprecated code
as well as dependencies from multiple versions
Currently JavaDoc is generated for many classes that don't need it.
JavaDoc should be reserved for user-facing classes (e.g. those used by
client application developers and developers embedding a broker into
their application). This commit narrows down the configuration to just
the classes that are needed. This will save time during release builds,
and save disk space wherever these files are stored (e.g. Apache
website).
Gary Tully
Domenico Francesco Bruscino
Justin Bertram
Clebert Suconic
Jan Šmucr
Alexey Markevich
Maverick19841972
Emmanuel Hugonnet
Robbie Gemmell
Chao Wang
Dries Harnie