Package org.apache.druid.query.extraction

Class DimExtractionFn

java.lang.Object

org.apache.druid.query.extraction.DimExtractionFn

All Implemented Interfaces:

Cacheable, ExtractionFn

Direct Known Subclasses:

FunctionalExtraction, LowerExtractionFn, MatchingDimExtractionFn, RegexDimExtractionFn, SearchQuerySpecDimExtractionFn, StringFormatExtractionFn, StrlenExtractionFn, SubstringDimExtractionFn, TimeDimExtractionFn, UpperExtractionFn

public abstract class DimExtractionFn
extends Object
implements ExtractionFn

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.druid.query.extraction.ExtractionFn

ExtractionFn.ExtractionType

Constructor Summary

Constructors

Constructor	Description
DimExtractionFn()

Method Summary

Modifier and Type	Method	Description
String	apply(long value)	The "extraction" function.
String	apply(Object value)	The "extraction" function.

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.java.util.common.Cacheable

getCacheKey

Methods inherited from interface org.apache.druid.query.extraction.ExtractionFn

apply, getExtractionType, preservesOrdering

Constructor Detail

DimExtractionFn

public DimExtractionFn()

Method Detail

apply

@Nullable
public String apply(@Nullable
                    Object value)

Description copied from interface: ExtractionFn

The "extraction" function. This should map an Object into some String value.

In order to maintain the "null and empty string are equivalent" semantics that Druid provides, the empty string is considered invalid output for this method and should instead return null. This is a contract on the method rather than enforced at a lower level in order to eliminate a global check for extraction functions that do not already need one.

Specified by:

apply in interface ExtractionFn

Parameters:

value - the original value of the dimension

Returns:

a value that should be used instead of the original

apply

public String apply(long value)

Description copied from interface: ExtractionFn

The "extraction" function. This should map a long value into some String value.

Like ExtractionFn.apply(Object), the empty string is considered invalid output for this method and it should instead return null.

Specified by:

apply in interface ExtractionFn

Parameters:

value - the original value of the dimension

Returns:

a value that should be used instead of the original