Package org.apache.commons.collections4.map

Class AbstractMapDecorator<K,V>

java.lang.Object

org.apache.commons.collections4.map.AbstractIterableMap<K,V>

org.apache.commons.collections4.map.AbstractMapDecorator<K,V>

Type Parameters:

K - the type of the keys in the map

V - the type of the values in the map

All Implemented Interfaces:

Map<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>

Direct Known Subclasses:

AbstractBidiMapDecorator, AbstractOrderedMapDecorator, AbstractSortedMapDecorator, DefaultedMap, FixedSizeMap, LazyMap, ListOrderedMap, MultiKeyMap, MultiValueMap, PassiveExpiringMap, PredicatedMap, TransformedMap, UnmodifiableMap

public abstract class AbstractMapDecorator<K,V>
extends AbstractIterableMap<K,V>

Provides a base decorator that enables additional functionality to be added to a Map via decoration.

Methods are forwarded directly to the decorated map.

This implementation does not perform any special processing with entrySet(), keySet() or values(). Instead it simply returns the set/collection from the wrapped map. This may be undesirable, for example if you are trying to write a validating implementation it would provide a loophole around the validation. But, you might want that loophole, so this class is kept simple.

Since:

3.0

Nested Class Summary

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

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

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractMapDecorator()	Constructor only used in deserialization, do not use otherwise.
protected	AbstractMapDecorator(Map<K,V> map)	Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method	Description
void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
protected Map<K,V>	decorated()	Gets the map being decorated.
Set<Map.Entry<K,V>>	entrySet()
boolean	equals(Object object)
V	get(Object key)
int	hashCode()
boolean	isEmpty()
Set<K>	keySet()
V	put(K key, V value)	Note that the return type is Object, rather than V as in the Map interface.
void	putAll(Map<? extends K,? extends V> mapToCopy)
V	remove(Object key)
int	size()
String	toString()
Collection<V>	values()

Methods inherited from class org.apache.commons.collections4.map.AbstractIterableMap

mapIterator

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

AbstractMapDecorator

protected AbstractMapDecorator()

Constructor only used in deserialization, do not use otherwise.

Since:

3.1

AbstractMapDecorator

protected AbstractMapDecorator(Map<K,V> map)

Constructor that wraps (not copies).

Parameters:

map - the map to decorate, must not be null

Throws:

NullPointerException - if the map is null

Method Detail

decorated

protected Map<K,V> decorated()

Gets the map being decorated.

Returns:

the decorated map

clear

public void clear()

See Also:

Map.clear()

containsKey

public boolean containsKey(Object key)

Parameters:

key - key whose presence in this map is to be tested

Returns:

true if this map contains a mapping for the specified key

See Also:

Map.containsKey(Object)

containsValue

public boolean containsValue(Object value)

Parameters:

value - value whose presence in this map is to be tested

Returns:

true if this map maps one or more keys to the specified value

See Also:

Map.containsValue(Object)

entrySet

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

Returns:

a set view of the mappings contained in this map

See Also:

Map.entrySet()

get

public V get(Object key)

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which the specified key is mapped, or null if this map contains no mapping for the key

See Also:

Map.get(Object)

isEmpty

public boolean isEmpty()

Returns:

true if this map contains no key-value mappings

See Also:

Map.isEmpty()

keySet

public Set<K> keySet()

Returns:

a set view of the keys contained in this map

See Also:

Map.keySet()

put

public V put(K key,
             V value)

Description copied from interface: Put

Note that the return type is Object, rather than V as in the Map interface. See the class Javadoc for further info.

Parameters:

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

the previous value associated with key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with key, if the implementation supports null values.)

See Also:

Map.put(Object, Object)

putAll

public void putAll(Map<? extends K,? extends V> mapToCopy)

Parameters:

mapToCopy - mappings to be stored in this map

See Also:

Map.putAll(Map)

remove

public V remove(Object key)

Parameters:

key - key whose mapping is to be removed from the map

Returns:

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

See Also:

Map.remove(Object)

size

public int size()

Returns:

the number of key-value mappings in this map

See Also:

Map.size()

values

public Collection<V> values()

Returns:

a collection view of the values contained in this map

See Also:

Map.values()

equals

public boolean equals(Object object)

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class Object

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<K,V>

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object