Package org.apache.druid.query.lookup

Class ImmutableLookupMap.ImmutableLookupExtractor

java.lang.Object

org.apache.druid.query.lookup.LookupExtractor

org.apache.druid.query.lookup.ImmutableLookupMap.ImmutableLookupExtractor

Enclosing class:

ImmutableLookupMap

public class ImmutableLookupMap.ImmutableLookupExtractor
extends LookupExtractor

Method Summary

Modifier and Type	Method	Description
String	apply(String key)	Apply a particular lookup methodology to the input string
Map<String,String>	asMap()	Returns a Map view of this lookup extractor.
long	estimateHeapFootprint()	Estimated heap footprint of this object.
byte[]	getCacheKey()	Create a cache key for use in results caching
boolean	isOneToOne()
boolean	supportsAsMap()	Returns whether this lookup extractor's LookupExtractor.asMap() will return a valid map.
protected List<String>	unapply(String value)	Reverse lookup from a given value.

Methods inherited from class org.apache.druid.query.lookup.LookupExtractor

applyAll, unapplyAll

Methods inherited from class java.lang.Object

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

Method Detail

apply

@Nullable
public String apply(@Nullable
                    String key)

Description copied from class: LookupExtractor

Apply a particular lookup methodology to the input string

Specified by:

apply in class LookupExtractor

Parameters:

key - The value to apply the lookup to.

Returns:

The value for this key, or null when key is `null` or when key cannot have the lookup applied to it and should be treated as missing.

unapply

protected List<String> unapply(@Nullable
                               String value)

Description copied from class: LookupExtractor

Reverse lookup from a given value. Used by the default implementation of LookupExtractor.unapplyAll(Set). Otherwise unused. Implementations that override LookupExtractor.unapplyAll(Set) may throw UnsupportedOperationException from this method.

Specified by:

unapply in class LookupExtractor

Parameters:

value - the value to apply the reverse lookup.

Returns:

the list of keys that maps to the provided value. In SQL-compatible null handling mode, null keys are omitted.

supportsAsMap

public boolean supportsAsMap()

Description copied from class: LookupExtractor

Returns whether this lookup extractor's LookupExtractor.asMap() will return a valid map.

Specified by:

supportsAsMap in class LookupExtractor

asMap

public Map<String,String> asMap()

Description copied from class: LookupExtractor

Returns a Map view of this lookup extractor. The map may change along with the underlying lookup data.

Specified by:

asMap in class LookupExtractor

isOneToOne

public boolean isOneToOne()

Overrides:

isOneToOne in class LookupExtractor

estimateHeapFootprint

public long estimateHeapFootprint()

Description copied from class: LookupExtractor

Estimated heap footprint of this object. Not guaranteed to be accurate. For example, some implementations return zero even though they do use on-heap structures. However, the most common classes, MapLookupExtractor and ImmutableLookupMap, do have reasonable implementations. This API is provided for best-effort memory management and monitoring.

Overrides:

estimateHeapFootprint in class LookupExtractor

getCacheKey

public byte[] getCacheKey()

Description copied from class: LookupExtractor

Create a cache key for use in results caching

Specified by:

getCacheKey in class LookupExtractor

Returns:

A byte array that can be used to uniquely identify if results of a prior lookup can use the cached values