Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

public interface ConcurrentMap<K, V>

ExtendsMap<K, V>

Known subtypesConcurrentHashMap

A map whose compound operations are atomic. The four methods it declares are default methods of Map as well; an implementation makes them atomic.

Methods

`public abstract V putIfAbsent(K key, V value)`	If the specified key is not already associated with a value (or is mapped to `null`) associates it with the given value and returns `null`, else returns the current value.
`public abstract boolean remove(Object key, Object value)`	Removes the entry for the specified key only if it is currently mapped to the specified value.
`public abstract V replace(K key, V value)`	Replaces the entry for the specified key only if it is currently mapped to some value.
`public abstract boolean replace(K key, V oldValue, V newValue)`	Replaces the entry for the specified key only if currently mapped to the specified value.

Inherited nested types

From Map

Map.Entry

Inherited methods

From Map

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values, getOrDefault, forEach, replaceAll, computeIfAbsent, computeIfPresent, compute, merge, of, of, of, of, of, of, of, of, of, of, of, ofEntries, entry, copyOf

Method details

putIfAbsent

public abstract V putIfAbsent(K key, V value)

If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

remove

public abstract boolean remove(Object key, Object value)

Removes the entry for the specified key only if it is currently mapped to the specified value.

replace

public abstract V replace(K key, V value)

Replaces the entry for the specified key only if it is currently mapped to some value.

replace

public abstract boolean replace(K key, V oldValue, V newValue)

Replaces the entry for the specified key only if currently mapped to the specified value.