org.elasticsearch.common.collect

Class CopyOnWriteHashMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.elasticsearch.common.collect.CopyOnWriteHashMap<K,V>

All Implemented Interfaces:

Map<K,V>

public final class CopyOnWriteHashMap<K,V>
extends AbstractMap<K,V>

An immutable map whose writes result in a new copy of the map to be created. This is essentially a hash array mapped trie: inner nodes use a bitmap in order to map hashes to slots by counting ones. In case of a collision (two values having the same 32-bits hash), a leaf node is created which stores and searches for values sequentially. Reads and writes both perform in logarithmic time. Null keys and values are not supported. This structure might need to perform several object creations per write so it is better suited for work-loads that are not too write-intensive.

See Also:

the wikipedia page

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

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

Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
CopyOnWriteHashMap() Create a new empty map.

Method Summary

Methods

Modifier and Type	Method and Description
static <T> T[]	appendElement(T[] array, T element)
boolean	containsKey(Object key)
CopyOnWriteHashMap<K,V>	copyAndPut(K key, V value) Associate key with value and return a new copy of the hash table.
CopyOnWriteHashMap<K,V>	copyAndPutAll(Map<? extends K,? extends V> other) Same as copyAndPut(Object, Object) but for an arbitrary number of entries.
CopyOnWriteHashMap<K,V>	copyAndRemove(Object key) Remove the given key from this map.
CopyOnWriteHashMap<K,V>	copyAndRemoveAll(Collection<?> keys) Same as copyAndRemove(Object) but for an arbitrary number of entries.
static <K,V> CopyOnWriteHashMap<K,V>	copyOf(Map<? extends K,? extends V> map) Return a copy of the provided map.
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
static <T> T[]	insertElement(T[] array, T element, int index)
int	size()

Methods inherited from class java.util.AbstractMap

clear, clone, containsValue, equals, hashCode, isEmpty, keySet, put, putAll, remove, toString, values

Methods inherited from class java.lang.Object

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

Constructor Detail

CopyOnWriteHashMap

public CopyOnWriteHashMap()

Create a new empty map.

Method Detail

copyOf

public static <K,V> CopyOnWriteHashMap<K,V> copyOf(Map<? extends K,? extends V> map)

Return a copy of the provided map.

appendElement

public static <T> T[] appendElement(T[] array,
                    T element)

insertElement

public static <T> T[] insertElement(T[] array,
                    T element,
                    int index)

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class AbstractMap<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

Overrides:

get in class AbstractMap<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

Overrides:

size in class AbstractMap<K,V>

copyAndPut

public CopyOnWriteHashMap<K,V> copyAndPut(K key,
                                 V value)

Associate key with value and return a new copy of the hash table. The current hash table is not modified.

copyAndPutAll

public CopyOnWriteHashMap<K,V> copyAndPutAll(Map<? extends K,? extends V> other)

Same as copyAndPut(Object, Object) but for an arbitrary number of entries.

copyAndRemove

public CopyOnWriteHashMap<K,V> copyAndRemove(Object key)

Remove the given key from this map. The current hash table is not modified.

copyAndRemoveAll

public CopyOnWriteHashMap<K,V> copyAndRemoveAll(Collection<?> keys)

Same as copyAndRemove(Object) but for an arbitrary number of entries.

entrySet

public Set<Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface Map<K,V>

Specified by:

entrySet in class AbstractMap<K,V>