Package com.globalmentor.collections

Class DecoratorReadWriteLockReverseMap<K,V>

java.lang.Object

com.globalmentor.collections.ReadWriteLockDecorator

com.globalmentor.collections.DecoratorReadWriteLockMap<K,V>

com.globalmentor.collections.DecoratorReadWriteLockReverseMap<K,V>

Type Parameters:

K - The type of key used in the map.

V - The type of value stored in the map.

All Implemented Interfaces:

ReadWriteLockMap<K,V>, ReadWriteLockReverseMap<K,V>, ReverseMap<K,V>, ReadWriteLock, Map<K,V>

public class DecoratorReadWriteLockReverseMap<K,V>
extends DecoratorReadWriteLockMap<K,V>
implements ReadWriteLockReverseMap<K,V>

A thread-safe map decorator that allows many readers but only one writer to access a map at a time, and that also allows lookup of the map keys keyed to the values by decorating two maps. For operations that iterate over live map data, a read or write lock should be acquired before the call to acquire the data and held until the data is consumed.

Author:

Garret Wilson

Nested Class Summary

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

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

Field Summary

Fields inherited from class com.globalmentor.collections.DecoratorReadWriteLockMap

map

Constructor Summary

Constructors

Constructor	Description
DecoratorReadWriteLockReverseMap(Map<K,V> map, Map<V,K> reverseMap)	Map constructor with a default reentrant read/write lock.
DecoratorReadWriteLockReverseMap(Map<K,V> map, Map<V,K> reverseMap, ReadWriteLock lock)	Map and read/write lock constructor.

Method Summary

Modifier and Type	Method	Description
void	clear()
boolean	containsValue(Object value)
K	getKey(V value)	Returns the key that represents the given value.
V	put(K key, V value)
V	remove(Object key)
K	removeValue(V value)	Removes the mapping for a value from this map if it is present.

Methods inherited from class com.globalmentor.collections.DecoratorReadWriteLockMap

compute, computeIfAbsent, computeIfPresent, containsKey, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, putAll, putIfAbsent, remove, replace, replace, replaceAll, size, values

Methods inherited from class com.globalmentor.collections.ReadWriteLockDecorator

readLock, writeLock

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, containsKey, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, putAll, putIfAbsent, remove, replace, replace, replaceAll, size, values

Methods inherited from interface java.util.concurrent.locks.ReadWriteLock

readLock, writeLock

Constructor Details

DecoratorReadWriteLockReverseMap

public DecoratorReadWriteLockReverseMap(Map<K,V> map,
 Map<V,K> reverseMap)

Map constructor with a default reentrant read/write lock.

Parameters:

map - The map this map should decorate.

reverseMap - The map to contain reverse lookup values.

Throws:

NullPointerException - if the provided map and/or reverse map is null.

DecoratorReadWriteLockReverseMap

public DecoratorReadWriteLockReverseMap(Map<K,V> map,
 Map<V,K> reverseMap,
 ReadWriteLock lock)

Map and read/write lock constructor.

Parameters:

map - The map this map should decorate.

reverseMap - The map to contain reverse lookup values.

lock - The lock for controlling access to the map.

Throws:

NullPointerException - if the provided map, reverse map, and/or lock is null.

Method Details

getKey

public K getKey(V value)

Description copied from interface: ReverseMap

Returns the key that represents the given value.

Specified by:

getKey in interface ReverseMap<K,V>

Parameters:

value - The value whose associated key is to be returned.

Returns:

The key to which this map reverse maps the specified value, or null if the map contains no reverse mapping for this value.

See Also:

• Map.containsValue(Object)

removeValue

public K removeValue(V value)

Description copied from interface: ReverseMap

Removes the mapping for a value from this map if it is present.

Specified by:

removeValue in interface ReverseMap<K,V>

Parameters:

value - The value whose mapping is to be removed from the map.

Returns:

The previous key associated with the value, or null if there was no mapping for the value.

containsValue

public boolean containsValue(Object value)

Specified by:

containsValue in interface Map<K,V>

Overrides:

containsValue in class DecoratorReadWriteLockMap<K,V>

put

public V put(K key,
 V value)

Specified by:

put in interface Map<K,V>

Overrides:

put in class DecoratorReadWriteLockMap<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class DecoratorReadWriteLockMap<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class DecoratorReadWriteLockMap<K,V>