INT-3339: Add priority to the JdbcChannelMS

[artembilan]

JIRA: https://jira.spring.io/browse/INT-3339

[artembilan]

For more info: http://troels.arvin.dk/db/rdbms/#select-order_by

[garyrussell]

I see no issues so far but I agree we need a sequence.

I am not sure what you mean about GC, the query strings look like literals to me.

Maybe we can add ALTER TABLE scripts, to ease migration?

[artembilan]

you mean about GC

I mean my replaceFirst hack. However, Now I see a case, where I'm not right: the custom ChannelMessageStoreQueryProvider might not provide CREATED_DATE ASC clause and that my hack will be volnurability. So, I'll add new strategy methods to ChannelMessageStoreQueryProvider.

ALTER TABLE scripts, to ease migration

Actually it's simple task for DBA: to compare initial scripts from different version and write ALTER TABLE (and others) scripts. I'd say: let's provide them, but on demand!

[garyrussell]

I am ok with that, but let's add a note in the migration guide about the new columns added.

[artembilan]

Pushed entire priority stuff.
Tested on MySQL, too.
Still need sequence and Docs

[artembilan]

Pushed sequence stuff

[artembilan]

Pushed Docs.

All work is done. The Migration Guide note will be added after merge.

[garyrussell]

Why did you need to promote this method? ChannelMessageStores don't need to remove their groups.

[artembilan]

No, It's really useful - purge in terms of AMQP

[garyrussell]

That's all

[garyrussell]

We also need to state that you can't use the same message store for both queue and priority channels (even with different regions) because the priority setting applies to the entire store.

Using a priorityEnabled store with a QueueChannel would not produce the expected results.

[artembilan]

Pushed

[garyrussell]

Fails on Oracle

java.lang.AssertionError: 
Expected: an instance of java.lang.Long
     but: <1> is a java.math.BigDecimal
    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
    at org.junit.Assert.assertThat(Assert.java:865)
    at org.junit.Assert.assertThat(Assert.java:832)
    at org.springframework.integration.jdbc.store.channel.AbstractTxTimeoutMessageStoreTests.testMessageSequenceColumn(AbstractTxTimeoutMessageStoreTests.java:221)

[artembilan]

true. Can we compare just two Number ?

[garyrussell]

Yes, this works...

garyrussell@3515f95

[garyrussell]

LGTM; final polish here: garyrussell@a7f36af

[garyrussell]

Merged