MultiMap (Oracle Fusion Middleware Java API Reference for Oracle Extension SDK)

java.lang.Object
- oracle.javatools.util.MultiMap<K,V>

All Implemented Interfaces:

java.util.Map<K,java.util.Collection<V>>

Direct Known Subclasses:

DBObjectIDMultiMap
```
public class MultiMap<K,V>
extends java.lang.Object
implements java.util.Map<K,java.util.Collection<V>>
```
An object that maps keys to collections of values. MultiMap<K,V> is, in fact, a subtype of Map<K,Collection<V>>; this type adds a small number of methods that accept values of V directly, rather than values of Collection<V>.
MultiMap uses an underlying map to store the keys and associated collections, and uses reflection to create the collections when needed. From the default constructor, the underlying map is a LinkedHashMap, and the collections class is ArrayList; other constructors allow other classes to be specified (for example, ArraySortedSet for the collections class).

If the collection of values associated with a key becomes empty for any reason, the collection is removed from the map. This ensures, for example, that isEmpty() == (valuesSize() == 0) and that containsKey(key) == (valuesSize(key) > 0).

Nested Class Summary
- Nested classes/interfaces inherited from interface java.util.Map
  java.util.Map.Entry<K,V>

Constructor Summary

Constructors
Modifier	Constructor and Description
	`MultiMap()` Creates a new `MultiMap` based on a map of type `LinkedHashMap` and collections of type `ArrayList`.
	`MultiMap(java.lang.Class<? extends java.util.Collection> collectionClass)` Creates a new `MultiMap` based on a map of type `LinkedHashMap` and collections of a specified type.
	`MultiMap(java.lang.Class<? extends java.util.Map> mapClass, java.lang.Class<? extends java.util.Collection> collectionClass)` Creates a new `MultiMap` based on a map of a specified type and collections of a specified type.
`protected`	`MultiMap(java.util.Map<K,java.util.Collection<V>> delegate, java.lang.Class<? extends java.util.Collection> collectionClass)`
	`MultiMap(MultiMap<K,V> map)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(K key, V value)` Adds a value to the collection associated with a key.
`boolean`	`addAll(K key, java.util.Collection<V> values)` Adds a colleciton of values to the collection associated with a key.
`boolean`	`addAll(K key, V... values)` Adds an array of values to the collection associated with a key.
`boolean`	`addAll(java.util.Map<? extends K,V> map)` Adds each value in a map to the collection associated with its key.
`void`	`clear()`
`boolean`	`contains(K key, V value)` Gets whether the collection associated with a key contains a value.
`boolean`	`containsKey(java.lang.Object key)`
`boolean`	`containsValue(java.lang.Object value)`
`java.util.Set<java.util.Map.Entry<K,java.util.Collection<V>>>`	`entrySet()`
`boolean`	`equals(java.lang.Object o)`
`java.util.Collection<V>`	`get(java.lang.Object key)`
`static <K,V> MultiMap<K,V>`	`getMultiMap()` Creates a new `MultiMap` based on a map of type `LinkedHashMap` and collections of type `ArrayList`.
`static <K,V> MultiMap<K,V>`	`getMultiMap(java.lang.Class<? extends java.util.Collection> collectionClass)` Creates a new `MultiMap` based on a map of type `LinkedHashMap` and collections of a specified type.
`static <K,V> MultiMap<K,V>`	`getMultiMap(java.lang.Class<? extends java.util.Map> mapClass, java.lang.Class<? extends java.util.Collection> collectionClass)` Creates a new `MultiMap` based on a map of a specified type and collections of a specified type.
`int`	`hashCode()`
`boolean`	`isEmpty()`
`java.util.Set<K>`	`keySet()`
`int`	`keysSize()` Gets the number of keys in this map.
`java.util.Collection<V>`	`put(K key, java.util.Collection<V> values)`
`void`	`putAll(java.util.Map<? extends K,? extends java.util.Collection<V>> map)`
`java.util.Collection<V>`	`remove(java.lang.Object key)`
`V`	`removeValue(K key, V value)` Removes a value from the collection associated with a key.
`int`	`size()`
`java.lang.String`	`toString()`
`java.util.Collection<java.util.Collection<V>>`	`values()`
`int`	`valuesSize()` Gets the number of values in this map.
`int`	`valuesSize(K key)` Gets the number of values in this map associated with a key.

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
  - MultiMap
```
public MultiMap()
```
    Creates a new MultiMap based on a map of type LinkedHashMap and collections of type ArrayList.
  - MultiMap
```
public MultiMap(java.lang.Class<? extends java.util.Collection> collectionClass)
```
    Creates a new MultiMap based on a map of type LinkedHashMap and collections of a specified type.
  - MultiMap
```
public MultiMap(java.lang.Class<? extends java.util.Map> mapClass,
                java.lang.Class<? extends java.util.Collection> collectionClass)
```
    Creates a new MultiMap based on a map of a specified type and collections of a specified type.
  - MultiMap
```
protected MultiMap(java.util.Map<K,java.util.Collection<V>> delegate,
                   java.lang.Class<? extends java.util.Collection> collectionClass)
```
  - MultiMap
```
public MultiMap(MultiMap<K,V> map)
```
- Method Detail
  - getMultiMap
```
public static <K,V> MultiMap<K,V> getMultiMap()
```
    Creates a new MultiMap based on a map of type LinkedHashMap and collections of type ArrayList.
  - getMultiMap
```
public static <K,V> MultiMap<K,V> getMultiMap(java.lang.Class<? extends java.util.Collection> collectionClass)
```
    Creates a new MultiMap based on a map of type LinkedHashMap and collections of a specified type.
  - getMultiMap
```
public static <K,V> MultiMap<K,V> getMultiMap(java.lang.Class<? extends java.util.Map> mapClass,
                                              java.lang.Class<? extends java.util.Collection> collectionClass)
```
    Creates a new MultiMap based on a map of a specified type and collections of a specified type.
  - keysSize
```
public int keysSize()
```
    Gets the number of keys in this map. Same as size(), but provided for symmetry with valuesSize().
  - valuesSize
```
public int valuesSize()
```
    Gets the number of values in this map. This will be greater than or equal to the number of keys.
  - valuesSize
```
public int valuesSize(K key)
```
    Gets the number of values in this map associated with a key.
  - contains
```
public boolean contains(K key,
                        V value)
```
    Gets whether the collection associated with a key contains a value.
    
    See Also:
    
    Map.containsValue(Object), Collection.contains(java.lang.Object)
  - add
```
public boolean add(K key,
                   V value)
```
    Adds a value to the collection associated with a key.
    
    Returns:
    
    true if the collection of values associated with the key was modified.
    
    See Also:
    
    put(K, java.util.Collection<V>), Collection.add(E)
  - addAll
```
public boolean addAll(K key,
                      java.util.Collection<V> values)
```
    Adds a colleciton of values to the collection associated with a key.
    
    Returns:
    
    true if the collection of values associated with the key was modified.
  - addAll
```
public boolean addAll(K key,
                      V... values)
```
    Adds an array of values to the collection associated with a key.
    
    Returns:
    
    true if the collection of values associated with the key was modified.
  - addAll
```
public boolean addAll(java.util.Map<? extends K,V> map)
```
    Adds each value in a map to the collection associated with its key.
    
    Returns:
    
    true if any collection of values in this map was modified.
    
    See Also:
    
    putAll(java.util.Map<? extends K, ? extends java.util.Collection<V>>), Collection.addAll(java.util.Collection<? extends E>)
  - removeValue
```
public V removeValue(K key,
                     V value)
```
    Removes a value from the collection associated with a key.
    
    Returns:
    
    the value if it was present in the collection of values associated with the key, or null otherwise.
    
    See Also:
    
    remove(Object), Collection.remove(java.lang.Object)
  - size
```
public int size()
```
    Specified by:
    
    size in interface java.util.Map<K,java.util.Collection<V>>
  - isEmpty
```
public boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface java.util.Map<K,java.util.Collection<V>>
  - containsKey
```
public boolean containsKey(java.lang.Object key)
```
    Specified by:
    
    containsKey in interface java.util.Map<K,java.util.Collection<V>>
  - containsValue
```
public boolean containsValue(java.lang.Object value)
```
    Because of the potential ambiguity about whether the value is a V or a Collection<V>, this implementation returns true in either case.
    
    Specified by:
    
    containsValue in interface java.util.Map<K,java.util.Collection<V>>
  - get
```
public java.util.Collection<V> get(java.lang.Object key)
```
    Specified by:
    
    get in interface java.util.Map<K,java.util.Collection<V>>
  - put
```
public java.util.Collection<V> put(K key,
                                   java.util.Collection<V> values)
```
    Specified by:
    
    put in interface java.util.Map<K,java.util.Collection<V>>
    
    Throws:
    
    java.lang.IllegalArgumentException - if the type of the collection of values is not assignable to the collection class with which this multimap was constructed.
  - remove
```
public java.util.Collection<V> remove(java.lang.Object key)
```
    Specified by:
    
    remove in interface java.util.Map<K,java.util.Collection<V>>
  - putAll
```
public void putAll(java.util.Map<? extends K,? extends java.util.Collection<V>> map)
```
    Specified by:
    
    putAll in interface java.util.Map<K,java.util.Collection<V>>
    
    Throws:
    
    java.lang.IllegalArgumentException - if the type of a collection of values is not assignable to the collection class with which this multimap was constructed.
  - clear
```
public void clear()
```
    Specified by:
    
    clear in interface java.util.Map<K,java.util.Collection<V>>
  - keySet
```
public java.util.Set<K> keySet()
```
    Specified by:
    
    keySet in interface java.util.Map<K,java.util.Collection<V>>
  - values
```
public java.util.Collection<java.util.Collection<V>> values()
```
    Specified by:
    
    values in interface java.util.Map<K,java.util.Collection<V>>
  - entrySet
```
public java.util.Set<java.util.Map.Entry<K,java.util.Collection<V>>> entrySet()
```
    Specified by:
    
    entrySet in interface java.util.Map<K,java.util.Collection<V>>
  - equals
```
public boolean equals(java.lang.Object o)
```
    Specified by:
    
    equals in interface java.util.Map<K,java.util.Collection<V>>
    
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface java.util.Map<K,java.util.Collection<V>>
    
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class MultiMap<K,V>

Nested Class Summary

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

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Map

Constructor Detail

MultiMap

MultiMap

MultiMap

MultiMap

MultiMap

Method Detail

getMultiMap

getMultiMap

getMultiMap

keysSize

valuesSize

valuesSize

contains

add

addAll

addAll

addAll

removeValue

size

isEmpty

containsKey

containsValue

get

put

remove

putAll

clear

keySet

values

entrySet

equals

hashCode

toString