Any multi-channel router should support channel name patterns [INT-1189]

Mark Fisher opened INT-1189 and commented

Currently, the multi-channel routers are required to return 0 or more channel instances or channel names. This is typically done by returning an array or Collection (or having an equivalent type of evaluation result from a SpEL expression).

We should also add support for basic wildcard matching (e.g. "bank.prime.*" would match any channel whose name begins with "bank.prime.").

The most elegant solution is probably to change the ChannelResolver strategy interface so that it supports a multi-return value option. The only method currently defined on the interface is:

MessageChannel resolveChannelName(String channelName);

We could add:

Collection<MessageChannel> resolveChannelPattern(String channelPattern);

The question is of course if we need to worry about backwards compatibility. It would be much nicer to have a single interface rather than having to extend ChannelResolver (which inevitably leads to instanceof checks). My initial feeling is that implementing ChannelResolver is a rather advanced extension. In fact, I'd be surprised if more than a handful of SI users have ever done it. Those users would probably be the least concerned if we add a method to the interface.

Affects: 2.0 M4

Issue Links:

• #5375 Refactor router hierarchy to provide consistent approach for managing router mappings dynamically (e.g., ControlBus)

Start with the ChannelResolver interface and the multi-channel router implementations described in the issue. Review linked issue #5375 and assess the proposed pattern-resolution API, backwards-compatibility impact, and how completion would be verified across affected routers.