Package org.apache.druid.query.lookup

Class ImmutableLookupMap

java.lang.Object

com.google.common.collect.ForwardingObject

com.google.common.collect.ForwardingMap<String,String>

org.apache.druid.query.lookup.ImmutableLookupMap

All Implemented Interfaces:

Map<String,String>

public final class ImmutableLookupMap
extends com.google.common.collect.ForwardingMap<String,String>

Similar to MapLookupExtractor, but immutable, and also reversible without iterating the entire map. Forward lookup, ImmutableLookupMap.ImmutableLookupExtractor.apply(String), is implemented using an Object2IntOpenHashMap with load factor LOAD_FACTOR. The value of the map is an index into keys and ForwardingMap.values(). Reverse lookup, ImmutableLookupMap.ImmutableLookupExtractor.unapply(String), is implemented using binary search through ForwardingMap.values(). The keys and ForwardingMap.values() lists are both sorted by value using VALUE_COMPARATOR. Relative to MapLookupExtractor backed by Java HashMap, this map has been observed to have somewhat lower footprint, same performance for ImmutableLookupMap.ImmutableLookupExtractor.apply(String), and significantly faster for ImmutableLookupMap.ImmutableLookupExtractor.unapply(String). It should be used whenever the map does not need to be mutated.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	ImmutableLookupMap.ImmutableLookupExtractor

Nested classes/interfaces inherited from class com.google.common.collect.ForwardingMap

com.google.common.collect.ForwardingMap.StandardEntrySet, com.google.common.collect.ForwardingMap.StandardKeySet, com.google.common.collect.ForwardingMap.StandardValues

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K extends Object,V extends Object>

Method Summary

Modifier and Type	Method	Description
LookupExtractor	asLookupExtractor(boolean isOneToOne, Supplier<byte[]> cacheKey)
protected Map<String,String>	delegate()
static ImmutableLookupMap	fromMap(Map<String,String> srcMap)	Create an ImmutableLookupMap from a particular map.

Methods inherited from class com.google.common.collect.ForwardingMap

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, standardClear, standardContainsKey, standardContainsValue, standardEquals, standardHashCode, standardIsEmpty, standardPutAll, standardRemove, standardToString, values

Methods inherited from class com.google.common.collect.ForwardingObject

toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Method Detail

fromMap

public static ImmutableLookupMap fromMap(Map<String,String> srcMap)

Create an ImmutableLookupMap from a particular map. The provided map will not be stored in the returned ImmutableLookupMap.

delegate

protected Map<String,String> delegate()

Specified by:

delegate in class com.google.common.collect.ForwardingMap<String,String>

asLookupExtractor

public LookupExtractor asLookupExtractor(boolean isOneToOne,
                                         Supplier<byte[]> cacheKey)