Package ratpack.func

Interface MultiValueMap<K,V>

Type Parameters:

K - The type of key objects

V - The type of value objects

All Superinterfaces:

Map<K,V>

All Known Subinterfaces:

Form

public interface MultiValueMap<K,V>
extends Map<K,V>

A map that may contain multiple values for a given key, but typically only one value.

Unlike other multi map types, this type is optimized for the case where there is only one value for a key. The map acts just like a normal Map, but has extra methods for getting all values for a key.

All implementations of this type are immutable. Mutating operations throw UnsupportedOperationException.

Where there is multiple values for a given key, retrieving a single value will return the first value, where the first value is intrinsic to the service in which the map is being used.

Nested Class Summary

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

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

Method Summary

Modifier and Type	Method	Description
com.google.common.collect.ListMultimap<K,V>	asMultimap()
void	clear()	Throws UnsupportedOperationException.
static <K,V> MultiValueMap<K,V>	empty()
V	get(Object key)	Get the first value for the key, or null if there are no values for the key.
Map<K,List<V>>	getAll()	Returns a new view of the map where each map value is a list of all the values for the given key (i.e.
List<V>	getAll(K key)	All of the values for the given key.
V	put(K key, V value)	Throws UnsupportedOperationException.
void	putAll(Map<? extends K,? extends V> m)	Throws UnsupportedOperationException.
V	remove(Object key)	Throws UnsupportedOperationException.

Methods inherited from interface java.util.Map

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

Method Detail

empty

static <K,V> MultiValueMap<K,V> empty()

getAll

List<V> getAll(K key)

All of the values for the given key. An empty list if there are no values for the key.

The returned list is immutable.

Parameters:

key - The key to return all values of

Returns:

all of the values for the given key, or an empty list if there are no values for the key.

getAll

Map<K,List<V>> getAll()

Returns a new view of the map where each map value is a list of all the values for the given key (i.e. a traditional multi map).

The returned map is immutable.

Returns:

A new view of the map where each map value is a list of all the values for the given key

get

@Nullable
V get(Object key)

Get the first value for the key, or null if there are no values for the key.

Specified by:

get in interface Map<K,V>

Parameters:

key - The key to obtain the first value for

Returns:

The first value for the given key, or null if there are no values for the given key

put

V put(K key,
      V value)

Throws UnsupportedOperationException.

Specified by:

put in interface Map<K,V>

remove

V remove(Object key)

Throws UnsupportedOperationException.

Specified by:

remove in interface Map<K,V>

putAll

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

Throws UnsupportedOperationException.

Specified by:

putAll in interface Map<K,V>

clear

void clear()

Throws UnsupportedOperationException.

Specified by:

clear in interface Map<K,V>

asMultimap

com.google.common.collect.ListMultimap<K,V> asMultimap()