org.apache.hadoop.hbase.metrics.impl

Class RefCountingMap<K,V>

java.lang.Object

org.apache.hadoop.hbase.metrics.impl.RefCountingMap<K,V>

@InterfaceAudience.Private
class RefCountingMap<K,V>
extends Object

A map of K to V, but does ref counting for added and removed values. The values are not added directly, but instead requested from the given Supplier if ref count == 0. Each put() call will increment the ref count, and each remove() will decrement it. The values are removed from the map iff ref count == 0.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	RefCountingMap.Payload<V>

Field Summary

Fields

Modifier and Type	Field and Description
private ConcurrentHashMap<K,RefCountingMap.Payload<V>>	map

Constructor Summary

Constructors

Constructor and Description
RefCountingMap()

Method Summary

Modifier and Type	Method and Description
(package private) void	clear()
(package private) V	get(K k)
(package private) Set<K>	keySet()
(package private) V	put(K k, Supplier<V> supplier)
(package private) V	remove(K k) Decrements the ref count of k, and removes from map if ref count == 0.
(package private) int	size()
(package private) Collection<V>	values()

Methods inherited from class java.lang.Object

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

Field Detail

map

private ConcurrentHashMap<K,RefCountingMap.Payload<V>> map

Constructor Detail

RefCountingMap

RefCountingMap()

Method Detail

put

V put(K k,
      Supplier<V> supplier)

get

V get(K k)

remove

V remove(K k)

Decrements the ref count of k, and removes from map if ref count == 0.

Parameters:

k - the key to remove

Returns:

the value associated with the specified key or null if key is removed from map.

clear

void clear()

keySet

Set<K> keySet()

values

Collection<V> values()

size

int size()