Package org.apache.commons.collections4.bidimap

Class UnmodifiableBidiMap<K,V>

java.lang.Object

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

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

org.apache.commons.collections4.bidimap.AbstractBidiMapDecorator<K,V>

org.apache.commons.collections4.bidimap.UnmodifiableBidiMap<K,V>

Type Parameters:

K - The type of the keys in this map

V - The type of the values in this map

All Implemented Interfaces:

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

public final class UnmodifiableBidiMap<K,V>
extends AbstractBidiMapDecorator<K,V>
implements Unmodifiable

Decorates another BidiMap to ensure it can't be altered.

Attempts to modify it will result in an UnsupportedOperationException.

Since:

3.0

Nested Class Summary

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

Map.Entry<K,V>

Method Summary

Modifier and Type	Method	Description
void	clear()	Always throws UnsupportedOperationException.
Set<Map.Entry<K,V>>	entrySet()	Gets a set view of the mappings contained in this map.
BidiMap<V,K>	inverseBidiMap()	Gets a view of this map where the keys and values are reversed.
Set<K>	keySet()	Gets a view of the keys contained in this map.
MapIterator<K,V>	mapIterator()	Obtains a MapIterator over the map.
V	put(K key, V value)	Always throws UnsupportedOperationException.
void	putAll(Map<? extends K,? extends V> mapToCopy)	Always throws UnsupportedOperationException.
V	remove(Object key)	Always throws UnsupportedOperationException.
K	removeValue(Object value)	Always throws UnsupportedOperationException.
static <K, V> BidiMap<K,V>	unmodifiableBidiMap(BidiMap<? extends K,? extends V> map)	Factory method to create an unmodifiable map.
Set<V>	values()	Gets a a collection view of the values contained in this map.

Methods inherited from class org.apache.commons.collections4.bidimap.AbstractBidiMapDecorator

decorated, getKey

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

containsKey, containsValue, equals, get, hashCode, isEmpty, size, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.collections4.Get

containsKey, containsValue, get, isEmpty, size

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, equals, forEach, get, getOrDefault, hashCode, isEmpty, merge, putIfAbsent, remove, replace, replace, replaceAll, size

Method Details

unmodifiableBidiMap

public static <K,
V> BidiMap<K,V> unmodifiableBidiMap(BidiMap<? extends K,? extends V> map)

Factory method to create an unmodifiable map.

If the map passed in is already unmodifiable, it is returned.

Type Parameters:

K - The key type

V - The value type

Parameters:

map - The map to decorate, must not be null

Returns:

An unmodifiable BidiMap

Throws:

NullPointerException - if map is null

Since:

4.0

clear

public void clear()

Always throws UnsupportedOperationException.

Specified by:

clear in interface Map<K,V>

Specified by:

clear in interface Put<K,V>

Overrides:

clear in class AbstractMapDecorator<K,V>

Throws:

UnsupportedOperationException - Always thrown.

See Also:

• Map.clear()

entrySet

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

Description copied from interface: Get

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

Specified by:

entrySet in interface Get<K,V>

Specified by:

entrySet in interface Map<K,V>

Overrides:

entrySet in class AbstractMapDecorator<K,V>

Returns:

A set view of the mappings contained in this map.

See Also:

• Map.entrySet()

inverseBidiMap

public BidiMap<V,K> inverseBidiMap()

Description copied from interface: BidiMap

Gets a view of this map where the keys and values are reversed.

Changes to one map will be visible in the other and vice versa. This enables both directions of the map to be accessed as a Map.

Implementations should seek to avoid creating a new object every time this method is called. See AbstractMap.values() etc. Calling this method on the inverse map should return the original.

Specified by:

inverseBidiMap in interface BidiMap<K,V>

Overrides:

inverseBidiMap in class AbstractBidiMapDecorator<K,V>

Returns:

An inverted bidirectional map

keySet

public Set<K> keySet()

Description copied from interface: Get

Gets a view of the keys contained in this map.

Specified by:

keySet in interface Get<K,V>

Specified by:

keySet in interface Map<K,V>

Overrides:

keySet in class AbstractMapDecorator<K,V>

Returns:

A set view of the keys contained in this map.

See Also:

• Map.keySet()

mapIterator

public MapIterator<K,V> mapIterator()

Description copied from class: AbstractIterableMap

Obtains a MapIterator over the map.

A map iterator is an efficient way of iterating over maps. There is no need to access the entry set or use Map Entry objects.

 IterableMap<String,Integer> map = new HashedMap<String,Integer>();
 MapIterator<String,Integer> it = map.mapIterator();
 while (it.hasNext()) {
   String key = it.next();
   Integer value = it.getValue();
   it.setValue(value + 1);
 }
 

Specified by:

mapIterator in interface IterableGet<K,V>

Overrides:

mapIterator in class AbstractBidiMapDecorator<K,V>

Returns:

A map iterator.

put

public V put(K key,
 V value)

Always throws UnsupportedOperationException.

Specified by:

put in interface BidiMap<K,V>

Specified by:

put in interface Map<K,V>

Specified by:

put in interface Put<K,V>

Overrides:

put in class AbstractMapDecorator<K,V>

Parameters:

key - Ignored.

value - Ignored.

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.)

Throws:

UnsupportedOperationException - Always thrown.

See Also:

• Map.put(Object, Object)

putAll

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

Always throws UnsupportedOperationException.

Specified by:

putAll in interface Map<K,V>

Specified by:

putAll in interface Put<K,V>

Overrides:

putAll in class AbstractMapDecorator<K,V>

Parameters:

mapToCopy - Ignored.

Throws:

UnsupportedOperationException - Always thrown.

See Also:

• Map.putAll(Map)

remove

public V remove(Object key)

Always throws UnsupportedOperationException.

Specified by:

remove in interface Get<K,V>

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class AbstractMapDecorator<K,V>

Parameters:

key - Ignored.

Returns:

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

Throws:

UnsupportedOperationException - Always thrown.

See Also:

• Map.remove(Object)

removeValue

public K removeValue(Object value)

Always throws UnsupportedOperationException.

Specified by:

removeValue in interface BidiMap<K,V>

Overrides:

removeValue in class AbstractBidiMapDecorator<K,V>

Parameters:

value - Ignored.

Returns:

The key that was removed, null if nothing removed.

Throws:

UnsupportedOperationException - Always thrown.

values

public Set<V> values()

Description copied from interface: Get

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

Specified by:

values in interface BidiMap<K,V>

Specified by:

values in interface Get<K,V>

Specified by:

values in interface Map<K,V>

Overrides:

values in class AbstractBidiMapDecorator<K,V>

Returns:

A collection view of the values contained in this map.

See Also:

• Map.values()