Package com.globalmentor.collections

Interface CollectionMap<K,V,C extends java.util.Collection<V>>

Type Parameters:

K - The type of key used in the map.

V - The type of value stored in each collection in the map.

C - The type of collection in which to store values in the map.

All Superinterfaces:

java.util.Map<K,C>

All Known Subinterfaces:

ReadWriteLockCollectionMap<K,V,C>

All Known Implementing Classes:

AbstractDecoratorCollectionMap, ArrayListHashMap, ArrayListMap, CopyOnWriteArrayListConcurrentHashMap, DecoratorReadWriteLockCollectionMap, HashSetHashMap, IdentityHashSetMap, SynchronizedCollectionMapDecorator, TreeSetMap

public interface CollectionMap<K,V,C extends java.util.Collection<V>>
extends java.util.Map<K,C>

A map that stores a collection of values for each key, using a pair of read and write locks to access its data, with special methods for retrieving single values.

Author:

Garret Wilson

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>

Method Summary

Modifier and Type	Method	Description
void	addItem(K key, V value)	Adds a value to the collection of values associated with the key.
C	createCollection()	Creates a collection in which to store values.
C	getCollection(K key)	Retrieves the collection of values associated with the given key.
V	getItem(K key)	Retrieves the first value from the collection of values, if any, associated with the key.
int	getItemCount(K key)	Retrieves the number of values in the collection, if any, associated with the key.
java.lang.Iterable<V>	getItems(K key)	Retrieves iterable access to all items, if any, associated with the given key
boolean	hasItems(K key)	Retrieves whether there are items in a collection associated with the key.
boolean	removeItem(K key, V value)	Removes the first occurence of the given value from the collection of values, if any, associated with the key.

Methods inherited from interface java.util.Map

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

Method Detail

getCollection

C getCollection(K key)

Retrieves the collection of values associated with the given key. If no collection of values is associated with the key, one will be created and added to the map.

Parameters:

key - The key in the map.

Returns:

The collection associated with the given key

See Also:

createCollection()

createCollection

C createCollection()

Creates a collection in which to store values.

Returns:

The collections with the values stored.

hasItems

boolean hasItems(K key)

Retrieves whether there are items in a collection associated with the key.

Parameters:

key - The key in the map.

Returns:

true if there is at least one item associated with the key.

getItemCount

int getItemCount(K key)

Retrieves the number of values in the collection, if any, associated with the key.

Parameters:

key - The key in the map.

Returns:

The number of items associated with the key.

addItem

void addItem(K key,
             V value)

Adds a value to the collection of values associated with the key. If no collection of values is associated with the key, one will be created and added to the map.

Parameters:

key - The key in the map.

value - The value to store in the collection.

getItem

V getItem(K key)

Retrieves the first value from the collection of values, if any, associated with the key.

Parameters:

key - The key in the map.

Returns:

The first value in the collection, or null if there is no collection associated with the key or no values in the collection.

See Also:

getCollection(Object)

getItems

java.lang.Iterable<V> getItems(K key)

Retrieves iterable access to all items, if any, associated with the given key

Parameters:

key - The key in the map.

Returns:

An object that will iterate all items, if any, associated with the given key.

removeItem

boolean removeItem(K key,
                   V value)

Removes the first occurence of the given value from the collection of values, if any, associated with the key. If all items from the collection are removed, the collection itself is removed from the map.

Parameters:

key - The key in the map.

value - The item to be removed from the collection, if present.

Returns:

true if an item was removed as a result of this call.