CandidateMatcher public matching functions

[bjacobowitz]

Description

In CandidateMatcher, increase visibility of matchQuery() (from protected), finish() and reportError() (from package-private) to public, so that a CandidateMatcher can be used effectively from outside the org.apache.lucene.monitor package.

Problem

The current access protections on CandidateMatcher make it infeasible for a user of the Lucene Monitor library to use an existing CandidateMatcher if they are outside the org.apache.lucene.monitor package (e.g. as part of the implementation of their own CandidateMatcher).

For example, a user working outside of the org.apache.lucene.monitor package could not build their own version of ParallelMatcher by making use of the matcher from QueryMatch.SIMPLE_MATCHER, because they cannot access matchQuery, reportError or finish on it.

Solution

This PR takes the simplest solution of increase the visibility of those functions in CandidateMatcher to public. This also requires modifying some existing CandidateMatcher implementations that override protected matchQuery() to instead override public matchQuery().

I've also added some just-compile tests in a subpackage org.apache.lucene.monitor.otherpackage, which call the newly-public functions to verify that they are accessible from outside the org.apache.lucene.monitor package.

See previous discussion of this approach and alternatives in #13109.

Merge Request

If this PR gets merged, can you please use my [email protected] email address for the squash+merge. Thank you.

[romseygeek]

Thanks @bjacobowitz, this looks great! Can you also create a CHANGES.txt entry under 'API changes'?

[romseygeek]

Using a MemoryIndex here would probably be simpler?

[romseygeek]

Thanks @bjacobowitz!