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:

java.util.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

java.util.Map.Entry<K extends java.lang.Object,V extends java.lang.Object>

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all of the mappings from this map.
boolean	containsKey(java.lang.Object key)	Tests for presence of a given key.
boolean	containsValue(java.lang.Object value)	Tests for presence of a given value.
protected java.util.Map<K,V>	decorated()	Gets the map being decorated.
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()	Gets a set view of the mappings contained in this map.
boolean	equals(java.lang.Object object)
V	get(java.lang.Object key)	Gets a value at a given key.
int	hashCode()
boolean	isEmpty()	Tests whether this instance contains any key-value mappings.
java.util.Set<K>	keySet()	Gets a view of the keys contained in this map.
V	put(K key, V value)	Associates the specified value with the specified key in this map.
void	putAll(java.util.Map<? extends K,? extends V> mapToCopy)	Copies all of the mappings from the specified map to this map.
V	remove(java.lang.Object key)	Remove a key-value mappings.
int	size()	Gets the number of key-value mappings in this map.
java.lang.String	toString()
java.util.Collection<V>	values()	Gets a a collection view of the values contained in this map.

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(java.util.Map<K,V> map)

Constructor that wraps (not copies).

Parameters:

map - the map to decorate, must not be null

Throws:

java.lang.NullPointerException - if the map is null

Method Detail

clear

public void clear()

Description copied from interface: Put

Removes all of the mappings from this map.

See Also:

Map.clear()

containsKey

public boolean containsKey(java.lang.Object key)

Description copied from interface: Get

Tests for presence of a given 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(java.lang.Object value)

Description copied from interface: Get

Tests for presence of a given 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)

decorated

protected java.util.Map<K,V> decorated()

Gets the map being decorated.

Returns:

the decorated map

entrySet

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

Description copied from interface: Get

Gets a set view of the mappings contained in this map.

Returns:

a set view of the mappings contained in this map.

See Also:

Map.entrySet()

equals

public boolean equals(java.lang.Object object)

Specified by:

equals in interface java.util.Map<K,V>

Overrides:

equals in class java.lang.Object

get

public V get(java.lang.Object key)

Description copied from interface: Get

Gets a value at a given 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)

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<K,V>

Overrides:

hashCode in class java.lang.Object

isEmpty

public boolean isEmpty()

Description copied from interface: Get

Tests whether this instance contains any key-value mappings.

Returns:

true if this map contains no key-value mappings

See Also:

Map.isEmpty()

keySet

public java.util.Set<K> keySet()

Description copied from interface: Get

Gets a view of the keys contained in this map.

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

Associates the specified value with the specified key in this map.

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(java.util.Map<? extends K,? extends V> mapToCopy)

Description copied from interface: Put

Copies all of the mappings from the specified map to this map.

Parameters:

mapToCopy - mappings to be stored in this map

See Also:

Map.putAll(Map)

remove

public V remove(java.lang.Object key)

Description copied from interface: Get

Remove a key-value mappings.

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()

Description copied from interface: Get

Gets the number of key-value mappings in this map.

Returns:

the number of key-value mappings in this map.

See Also:

Map.size()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

values

public java.util.Collection<V> values()

Description copied from interface: Get

Gets a a collection view of the values contained in this map.

Returns:

a collection view of the values contained in this map.

See Also:

Map.values()