org.apache.druid.segment.selector.settable

Class SettableDimensionValueSelector

java.lang.Object

org.apache.druid.segment.selector.settable.SettableDimensionValueSelector

All Implemented Interfaces:

HotLoopCallee, BaseDoubleColumnValueSelector, BaseFloatColumnValueSelector, BaseLongColumnValueSelector, BaseNullableColumnValueSelector, BaseObjectColumnValueSelector<Object>, ColumnValueSelector<Object>, DimensionSelector, SettableColumnValueSelector<Object>

public class SettableDimensionValueSelector
extends Object
implements DimensionSelector, SettableColumnValueSelector<Object>

Settable implementation of DimensionSelector.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.druid.segment.DimensionSelector

DimensionSelector.NullDimensionSelectorHolder

Field Summary

Fields inherited from interface org.apache.druid.segment.DimensionSelector

CARDINALITY_UNKNOWN

Fields inherited from interface org.apache.druid.segment.ColumnValueSelector

EMPTY_ARRAY

Constructor Summary

Constructors

Constructor and Description
SettableDimensionValueSelector()

Method Summary

Modifier and Type	Method and Description
Class	classOfObject()
Object	getObject()
IndexedInts	getRow() Returns the indexed values at the current position in this DimensionSelector.
int	getValueCardinality() Value cardinality is the cardinality of the different occurring values.
IdLookup	idLookup() Returns IdLookup if available for this DimensionSelector, or null.
String	lookupName(int id) The Name is the String name of the actual field.
ValueMatcher	makeValueMatcher(com.google.common.base.Predicate<String> predicate)
ValueMatcher	makeValueMatcher(String value)
boolean	nameLookupPossibleInAdvance() Returns true if it is possible to DimensionSelector.lookupName(int) by ids from 0 to DimensionSelector.getValueCardinality() before the rows with those ids are returned.
void	setValueFrom(ColumnValueSelector<?> selector)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.druid.segment.DimensionSelector

constant, constant, defaultGetObject, getDouble, getFloat, getLong, isNilSelector, isNull

Methods inherited from interface org.apache.druid.segment.selector.settable.SettableColumnValueSelector

inspectRuntimeShape

Constructor Detail

SettableDimensionValueSelector

public SettableDimensionValueSelector()

Method Detail

setValueFrom

public void setValueFrom(ColumnValueSelector<?> selector)

Specified by:

setValueFrom in interface SettableColumnValueSelector<Object>

getRow

public IndexedInts getRow()

Description copied from interface: DimensionSelector

Returns the indexed values at the current position in this DimensionSelector. IMPORTANT. The returned IndexedInts object could generally be reused inside the implementation of DimensionSelector, i. e. this method could always return the same object for the same selector. Users of this API, such as Aggregator.aggregate(), BufferAggregator.aggregate(java.nio.ByteBuffer, int), AggregateCombiner.reset(org.apache.druid.segment.ColumnValueSelector), AggregateCombiner.fold(org.apache.druid.segment.ColumnValueSelector) should be prepared for that and not storing the object returned from this method in their state, assuming that the object will remain unchanged even when the position of the selector changes. This may not be the case.

Specified by:

getRow in interface DimensionSelector

makeValueMatcher

public ValueMatcher makeValueMatcher(@Nullable
                                     String value)

Specified by:

makeValueMatcher in interface DimensionSelector

Parameters:

value - nullable dimension value

makeValueMatcher

public ValueMatcher makeValueMatcher(com.google.common.base.Predicate<String> predicate)

Specified by:

makeValueMatcher in interface DimensionSelector

getValueCardinality

public int getValueCardinality()

Description copied from interface: DimensionSelector

Value cardinality is the cardinality of the different occurring values. If there were 4 rows: A,B A B A Value cardinality would be 2. Cardinality may be unknown (e.g. the selector used by IncrementalIndex while reading input rows), in which case this method will return -1. If cardinality is unknown, you should assume this dimension selector has no dictionary, and avoid storing ids, calling "lookupId", or calling "lookupName" outside of the context of operating on a single row.

Specified by:

getValueCardinality in interface DimensionSelector

Returns:

the value cardinality, or -1 if unknown.

lookupName

@Nullable
public String lookupName(int id)

Description copied from interface: DimensionSelector

The Name is the String name of the actual field. It is assumed that storage layers convert names into id values which can then be used to get the string value. For example A,B A A,B B getRow() would return getRow(0) => [0 1] getRow(1) => [0] getRow(2) => [0 1] getRow(3) => [1] and then lookupName would return: lookupName(0) => A lookupName(1) => B

Specified by:

lookupName in interface DimensionSelector

Parameters:

id - id to lookup the field name for

Returns:

the field name for the given id

nameLookupPossibleInAdvance

public boolean nameLookupPossibleInAdvance()

Description copied from interface: DimensionSelector

Returns true if it is possible to DimensionSelector.lookupName(int) by ids from 0 to DimensionSelector.getValueCardinality() before the rows with those ids are returned.

Returns false if DimensionSelector.lookupName(int) could be called with ids, returned from the most recent call of DimensionSelector.getRow() on this DimensionSelector, but not earlier. If DimensionSelector.getValueCardinality() of this DimensionSelector additionally returns DimensionSelector.CARDINALITY_UNKNOWN, lookupName() couldn't be called with ids, returned by not the most recent call of DimensionSelector.getRow(), i. e. names for ids couldn't be looked up "later". If DimensionSelector.getValueCardinality() returns a non-negative number, lookupName() could be called with any ids, returned from #getRow() since the creation of this DimensionSelector.

If DimensionSelector.lookupName(int) is called with an ineligible id, result is undefined: exception could be thrown, or null returned, or some other random value.

Specified by:

nameLookupPossibleInAdvance in interface DimensionSelector

idLookup

@Nullable
public IdLookup idLookup()

Description copied from interface: DimensionSelector

Returns IdLookup if available for this DimensionSelector, or null.

Specified by:

idLookup in interface DimensionSelector

getObject

@Nullable
public Object getObject()

Specified by:

getObject in interface BaseObjectColumnValueSelector<Object>

classOfObject

public Class classOfObject()

Specified by:

classOfObject in interface BaseObjectColumnValueSelector<Object>