K - the type of keys maintained by this mapV - the type of mapped valuespublic final class ConcurrentWeakKeyHashMap<K,V> extends AbstractMap<K,V> implements ConcurrentMap<K,V>
ConcurrentMap which is similar to ConcurrentHashMap.| Modifier and Type | Class and Description |
|---|---|
static interface |
ConcurrentWeakKeyHashMap.ReusableIterator<E> |
AbstractMap.SimpleImmutableEntry<K,V>| Constructor and Description |
|---|
ConcurrentWeakKeyHashMap()
Creates a new, empty map with a default initial capacity (16), reference types (weak keys, strong values),
default load factor (0.75) and concurrencyLevel (16).
|
ConcurrentWeakKeyHashMap(int initialCapacity)
Creates a new, empty map with the specified initial capacity, and with default reference types (weak keys, strong
values), load factor (0.75) and concurrencyLevel (16).
|
ConcurrentWeakKeyHashMap(int initialCapacity,
float loadFactor)
Creates a new, empty map with the specified initial capacity and load factor and with the default reference types
(weak keys, strong values), and concurrencyLevel (16).
|
ConcurrentWeakKeyHashMap(int initialCapacity,
float loadFactor,
int concurrencyLevel)
Creates a new, empty map with the specified initial capacity, load factor and concurrency level.
|
ConcurrentWeakKeyHashMap(Map<? extends K,? extends V> m)
Creates a new map with the same mappings as the given map.
|
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Removes all of the mappings from this map.
|
boolean |
contains(Object value)
Legacy method testing if some key maps into the specified value in this table.
|
boolean |
containsKey(Object key)
Tests if the specified object is a key in this table.
|
boolean |
containsValue(Object value)
Returns true if this map maps one or more keys to the specified value.
|
Enumeration<V> |
elements()
Returns an enumeration of the values in this table.
|
Set<Map.Entry<K,V>> |
entrySet()
Returns a
Set view of the mappings contained in this map. |
V |
get(Object key)
Returns the value to which the specified key is mapped, or
null if this map contains no mapping for the
key. |
boolean |
isEmpty()
Returns true if this map contains no key-value mappings.
|
Enumeration<K> |
keys()
Returns an enumeration of the keys in this table.
|
Set<K> |
keySet()
Returns a
Set view of the keys contained in this map. |
void |
purgeStaleEntries()
Removes any stale entries whose keys have been finalized.
|
V |
put(K key,
V value)
Maps the specified key to the specified value in this table.
|
void |
putAll(Map<? extends K,? extends V> m)
Copies all of the mappings from the specified map to this one.
|
V |
putIfAbsent(K key,
V value) |
V |
remove(Object key)
Removes the key (and its corresponding value) from this map.
|
boolean |
remove(Object key,
Object value) |
V |
replace(K key,
V value) |
boolean |
replace(K key,
V oldValue,
V newValue) |
int |
size()
Returns the number of key-value mappings in this map.
|
Collection<V> |
values()
Returns a
Collection view of the values contained in this map. |
clone, equals, hashCode, toStringfinalize, getClass, notify, notifyAll, wait, wait, waitcompute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAllpublic ConcurrentWeakKeyHashMap(int initialCapacity,
float loadFactor,
int concurrencyLevel)
initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this
many elements.loadFactor - the load factor threshold, used to control resizing. Resizing may be performed when the
average number of elements per bin exceeds this threshold.concurrencyLevel - the estimated number of concurrently updating threads. The implementation performs
internal sizing to try to accommodate this many threads.IllegalArgumentException - if the initial capacity is negative or the load factor or concurrencyLevel are
nonpositive.public ConcurrentWeakKeyHashMap(int initialCapacity,
float loadFactor)
initialCapacity - The implementation performs internal sizing to accommodate this many elements.loadFactor - the load factor threshold, used to control resizing. Resizing may be performed when the
average number of elements per bin exceeds this threshold.IllegalArgumentException - if the initial capacity of elements is negative or the load factor is
nonpositivepublic ConcurrentWeakKeyHashMap(int initialCapacity)
initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this many
elements.IllegalArgumentException - if the initial capacity of elements is negative.public ConcurrentWeakKeyHashMap()
public ConcurrentWeakKeyHashMap(Map<? extends K,? extends V> m)
m - the mappublic boolean isEmpty()
public int size()
public V get(Object key)
null if this map contains no mapping for the
key.
More formally, if this map contains a mapping from a key k to a value v such that key.equals(k), then this method returns v; otherwise it returns null. (There can be at most one
such mapping.)
get in interface Map<K,V>get in class AbstractMap<K,V>NullPointerException - if the specified key is nullpublic boolean containsKey(Object key)
containsKey in interface Map<K,V>containsKey in class AbstractMap<K,V>key - possible keyNullPointerException - if the specified key is nullpublic boolean containsValue(Object value)
containsValue in interface Map<K,V>containsValue in class AbstractMap<K,V>value - value whose presence in this map is to be testedNullPointerException - if the specified value is nullpublic boolean contains(Object value)
containsValue(java.lang.Object), and exists solely to ensure full compatibility with class Hashtable, which supported this method prior to introduction of the Java Collections framework.value - a value to search forNullPointerException - if the specified value is nullpublic V put(K key, V value)
The value can be retrieved by calling the get method with a key that is equal to the original key.
put in interface Map<K,V>put in class AbstractMap<K,V>key - key with which the specified value is to be associatedvalue - value to be associated with the specified keyNullPointerException - if the specified key or value is nullpublic V putIfAbsent(K key, V value)
putIfAbsent in interface ConcurrentMap<K,V>putIfAbsent in interface Map<K,V>NullPointerException - if the specified key or value is nullpublic void putAll(Map<? extends K,? extends V> m)
public V remove(Object key)
remove in interface Map<K,V>remove in class AbstractMap<K,V>key - the key that needs to be removedNullPointerException - if the specified key is nullpublic boolean remove(Object key, Object value)
remove in interface ConcurrentMap<K,V>remove in interface Map<K,V>NullPointerException - if the specified key is nullpublic boolean replace(K key, V oldValue, V newValue)
replace in interface ConcurrentMap<K,V>replace in interface Map<K,V>NullPointerException - if any of the arguments are nullpublic V replace(K key, V value)
replace in interface ConcurrentMap<K,V>replace in interface Map<K,V>NullPointerException - if the specified key or value is nullpublic void clear()
public void purgeStaleEntries()
public Set<K> keySet()
Set view of the keys contained in this map. The set is backed by the map, so changes to the
map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding
mapping from this map, via the Iterator.remove, Set.remove, removeAll,
retainAll, and clear operations. It does not support the add or addAll
operations.
The view's iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the
iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
public Collection<V> values()
Collection view of the values contained in this map. The collection is backed by the map, so
changes to the map are reflected in the collection, and vice-versa. The collection supports element removal,
which removes the corresponding mapping from this map, via the Iterator.remove,
Collection.remove, removeAll, retainAll, and clear operations. It does not
support the add or addAll operations.
The view's iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the
iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
public Set<Map.Entry<K,V>> entrySet()
Set view of the mappings contained in this map. The set is backed by the map, so changes to the
map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding
mapping from the map, via the Iterator.remove, Set.remove, removeAll,
retainAll, and clear operations. It does not support the add or addAll
operations.
The view's iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the
iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
public Enumeration<K> keys()
keySet()public Enumeration<V> elements()
values()Copyright © 2018 JBoss, a division of Red Hat. All rights reserved.