Package org.apache.commons.collections4.trie

Class UnmodifiableTrie<K,V>

java.lang.Object

org.apache.commons.collections4.trie.UnmodifiableTrie<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:

Serializable, Map<K,V>, SortedMap<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, IterableSortedMap<K,V>, OrderedMap<K,V>, Put<K,V>, Trie<K,V>, Unmodifiable

public class UnmodifiableTrie<K,V>
extends Object
implements Trie<K,V>, Serializable, Unmodifiable

An unmodifiable Trie.

Since:

4.0

See Also:

• Serialized Form

Nested Class Summary

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

Map.Entry<K,V>

Constructor Summary

Constructors

Constructor	Description
UnmodifiableTrie(Trie<K,? extends V> trie)	Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method	Description
void	clear()	Always throws UnsupportedOperationException.
Comparator<? super K>	comparator()
boolean	containsKey(Object key)	Tests for presence of a given key.
boolean	containsValue(Object value)	Tests for presence of a given value.
Set<Map.Entry<K,V>>	entrySet()	Gets a set view of the mappings contained in this map.
boolean	equals(Object obj)
K	firstKey()	Gets the first key currently in this map.
V	get(Object key)	Gets a value at a given key.
int	hashCode()
SortedMap<K,V>	headMap(K toKey)
boolean	isEmpty()	Tests whether this instance contains any key-value mappings.
Set<K>	keySet()	Gets a view of the keys contained in this map.
K	lastKey()	Gets the last key currently in this map.
OrderedMapIterator<K,V>	mapIterator()	Obtains an OrderedMapIterator over the map.
K	nextKey(K key)	Gets the next key after the one specified.
SortedMap<K,V>	prefixMap(K key)	Returns a view of this Trie of all elements that are prefixed by the given key.
K	previousKey(K key)	Gets the previous key before the one specified.
V	put(K key, V value)	Always throws UnsupportedOperationException.
void	putAll(Map<? extends K,? extends V> m)	Always throws UnsupportedOperationException.
V	remove(Object key)	Always throws UnsupportedOperationException.
int	size()	Gets the number of key-value mappings in this map.
SortedMap<K,V>	subMap(K fromKey, K toKey)
SortedMap<K,V>	tailMap(K fromKey)
String	toString()
static <K, V> Trie<K,V>	unmodifiableTrie(Trie<K,? extends V> trie)	Factory method to create an unmodifiable trie.
Collection<V>	values()	Gets a a collection view of the values contained in this map.

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 Details

UnmodifiableTrie

public UnmodifiableTrie(Trie<K,? extends V> trie)

Constructor that wraps (not copies).

Parameters:

trie - The trie to decorate, must not be null

Throws:

NullPointerException - if trie is null

Method Details

unmodifiableTrie

public static <K,
V> Trie<K,V> unmodifiableTrie(Trie<K,? extends V> trie)

Factory method to create an unmodifiable trie.

Type Parameters:

K - the key type

V - the value type

Parameters:

trie - The trie to decorate, must not be null

Returns:

A new unmodifiable trie

Throws:

NullPointerException - if trie is null

clear

public void clear()

Always throws UnsupportedOperationException.

Specified by:

clear in interface Map<K,V>

Specified by:

clear in interface Put<K,V>

Throws:

UnsupportedOperationException - Always thrown.

See Also:

• Map.clear()

comparator

public Comparator<? super K> comparator()

Specified by:

comparator in interface SortedMap<K,V>

containsKey

public boolean containsKey(Object key)

Description copied from interface: Get

Tests for presence of a given key.

Specified by:

containsKey in interface Get<K,V>

Specified by:

containsKey in interface Map<K,V>

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)

Description copied from interface: Get

Tests for presence of a given value.

Specified by:

containsValue in interface Get<K,V>

Specified by:

containsValue in interface Map<K,V>

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()

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>

Specified by:

entrySet in interface SortedMap<K,V>

Returns:

A set view of the mappings contained in this map.

See Also:

• Map.entrySet()

equals

public boolean equals(Object obj)

Specified by:

equals in interface Map<K,V>

Overrides:

equals in class Object

firstKey

public K firstKey()

Description copied from interface: OrderedMap

Gets the first key currently in this map.

Specified by:

firstKey in interface OrderedMap<K,V>

Specified by:

firstKey in interface SortedMap<K,V>

Returns:

The first key currently in this map.

get

public V get(Object key)

Description copied from interface: Get

Gets a value at a given key.

Specified by:

get in interface Get<K,V>

Specified by:

get in interface Map<K,V>

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 Map<K,V>

Overrides:

hashCode in class Object

headMap

public SortedMap<K,V> headMap(K toKey)

Specified by:

headMap in interface SortedMap<K,V>

isEmpty

public boolean isEmpty()

Description copied from interface: Get

Tests whether this instance contains any key-value mappings.

Specified by:

isEmpty in interface Get<K,V>

Specified by:

isEmpty in interface Map<K,V>

Returns:

true if this map contains no key-value mappings.

See Also:

• Map.isEmpty()

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>

Specified by:

keySet in interface SortedMap<K,V>

Returns:

A set view of the keys contained in this map.

See Also:

• Map.keySet()

lastKey

public K lastKey()

Description copied from interface: OrderedMap

Gets the last key currently in this map.

Specified by:

lastKey in interface OrderedMap<K,V>

Specified by:

lastKey in interface SortedMap<K,V>

Returns:

The last key currently in this map.

mapIterator

public OrderedMapIterator<K,V> mapIterator()

Description copied from interface: OrderedMap

Obtains an OrderedMapIterator over the map.

An ordered map iterator is an efficient way of iterating over maps in both directions.

Specified by:

mapIterator in interface IterableGet<K,V>

Specified by:

mapIterator in interface OrderedMap<K,V>

Returns:

A map iterator.

nextKey

public K nextKey(K key)

Description copied from interface: OrderedMap

Gets the next key after the one specified.

Specified by:

nextKey in interface OrderedMap<K,V>

Parameters:

key - The key to search for next from.

Returns:

The next key, null if no match or at end.

prefixMap

public SortedMap<K,V> prefixMap(K key)

Description copied from interface: Trie

Returns a view of this Trie of all elements that are prefixed by the given key.

In a Trie with fixed size keys, this is essentially a Map.get(Object) operation.

For example, if the Trie contains 'Anna', 'Anael', 'Analu', 'Andreas', 'Andrea', 'Andres', and 'Anatole', then a lookup of 'And' would return 'Andreas', 'Andrea', and 'Andres'.

Specified by:

prefixMap in interface Trie<K,V>

Parameters:

key - The key used in the search.

Returns:

A SortedMap view of this Trie with all elements whose key is prefixed by the search key.

previousKey

public K previousKey(K key)

Description copied from interface: OrderedMap

Gets the previous key before the one specified.

Specified by:

previousKey in interface OrderedMap<K,V>

Parameters:

key - The key to search for previous from.

Returns:

The previous key, null if no match or at start.

put

public V put(K key,
 V value)

Always throws UnsupportedOperationException.

Specified by:

put in interface Map<K,V>

Specified by:

put in interface Put<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> m)

Always throws UnsupportedOperationException.

Specified by:

putAll in interface Map<K,V>

Specified by:

putAll in interface Put<K,V>

Parameters:

m - 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>

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)

size

public int size()

Description copied from interface: Get

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

Specified by:

size in interface Get<K,V>

Specified by:

size in interface Map<K,V>

Returns:

The number of key-value mappings in this map.

See Also:

• Map.size()

subMap

public SortedMap<K,V> subMap(K fromKey,
 K toKey)

Specified by:

subMap in interface SortedMap<K,V>

tailMap

public SortedMap<K,V> tailMap(K fromKey)

Specified by:

tailMap in interface SortedMap<K,V>

toString

public String toString()

Overrides:

toString in class Object

values

public Collection<V> values()

Description copied from interface: Get

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

Specified by:

values in interface Get<K,V>

Specified by:

values in interface Map<K,V>

Specified by:

values in interface SortedMap<K,V>

Returns:

A collection view of the values contained in this map.

See Also:

• Map.values()