* Add lastString and firstString aggregators extension
* Remove duplicated class
* Move first-last-string doc page to extensions-contrib
* Fix ObjectStrategy compare method
* Fix doc bad aggregatos type name
* Create FoldingAggregatorFactory classes to fix SegmentMetadataQuery
* Add getMaxStringBytes() method to support JSON serialization
* Fix null pointer exception at segment creation phase when the string value is null
* Control the valueSelector object class on BufferAggregators
* Perform all improvements
* Add java doc on SerializablePairLongStringSerde
* Refactor ObjectStraty compare method
* Remove unused ;
* Add aggregateCombiner unit tests. Rename BufferAggregators unit tests
* Remove unused imports
* Add license header
* Add class name to java doc class serde
* Throw exception if value is unsupported class type
* Move first-last-string extension into druid core
* Update druid core docs
* Fix null pointer exception when pair->string is null
* Add null control unit tests
* Remove unused imports
* Add first/last string folding aggregator on AggregatorsModule to support segment metadata query
* Change SerializablePairLongString to extend SerializablePair
* Change vars from public to private
* Convert vars to primitive type
* Clarify compare comment
* Change IllegalStateException to ISE
* Remove TODO comments
* Control possible null pointer exception
* Add @Nullable annotation
* Remove empty line
* Remove unused parameter type
* Improve AggregatorCombiner javadocs
* Add filterNullValues option at StringLast and StringFirst aggregators
* Add filterNullValues option at agg documentation
* Fix checkstyle
* Update header license
* Fix StringFirstAggregatorFactory.VALUE_COMPARATOR
* Fix StringFirstAggregatorCombiner
* Fix if condition at StringFirstAggregateCombiner
* Remove filterNullValues from string first/last aggregators
* Add isReset flag in FirstAggregatorCombiner
* Change Arrays.asList to Collections.singletonList
Originally written by @AlexanderSaydakov in druid-io/druid-io.github.io#448.
I also added redirects and updated links to point to the new
datasketches-extension.html landing page for the extension, rather than to
the old page about theta sketches.
* Add "round" option to cardinality and hyperUnique aggregators.
Also turn it on by default in SQL, to make math on distinct counts
work more as expected.
* Fix some compile errors.
* Fix test.
* Formatting.
* add first and last aggregator
* add test and fix
* moving around
* separate aggregator valueType
* address PR comment
* add finalize inner query and adjust v1 inner indexing
* better test and fixes
* java-util import fixes
* PR comments
* Add first/last aggs to ITWikipediaQueryTest
There is no such thing as a "Java aggregator" in Druid from a user's point of view, there are just native aggregator that happen to be implemented in Java.
This removes Filter.makeMatcher(ColumnSelectorFactory) and adds a
ValueMatcherFactory implementation to FilteredAggregatorFactory so it can
take advantage of existing makeMatcher(ValueMatcherFactory) implementations.
This patch also removes the Bound-based method from ValueMatcherFactory. Its
only user was the SpatialFilter, which could use the Predicate-based method.
Fixes#2604.