Inheritance diagram for java.util.LinkedHashMap< K, V >:

Classes
class	LinkedHashMapEntry

class	LinkedHashMapEntrySet

Public Member Functions
	LinkedHashMap ()

	LinkedHashMap (int s)

	LinkedHashMap (int s, float lf)

	LinkedHashMap (int s, float lf, boolean order)

	LinkedHashMap (Map<? extends K, ? extends V > m)

boolean	containsValue (Object value)

V	get (Object key)

V	put (K key, V value)

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

Set< K >	keySet ()

Collection< V >	values ()

V	remove (Object key)

void	clear ()

Public Member Functions inherited from java.util.HashMap< K, V >
	HashMap ()

	HashMap (int capacity)

	HashMap (int capacity, float loadFactor)

	HashMap (Map<? extends K, ? extends V > map)

void	clear ()

Object	clone ()

boolean	containsKey (Object key)

boolean	containsValue (Object value)

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

V	get (Object key)

boolean	isEmpty ()

Set< K >	keySet ()

V	put (K key, V value)

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

V	remove (Object key)

int	size ()

Collection< V >	values ()

Public Member Functions inherited from java.util.AbstractMap< K, V >
void	clear ()

boolean	containsKey (Object key)

boolean	containsValue (Object value)

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

boolean	equals (Object object)

V	get (Object key)

int	hashCode ()

boolean	isEmpty ()

Set< K >	keySet ()

V	put (K key, V value)

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

V	remove (Object key)

int	size ()

String	toString ()

Collection< V >	values ()

Public Member Functions inherited from java.util.Map< K, V >
void	putAll (Map<? extends K,? extends V > map)

Protected Member Functions
boolean	removeEldestEntry (Map.Entry< K, V > eldest)

Protected Member Functions inherited from java.util.AbstractMap< K, V >
Object	clone () throws CloneNotSupportedException

Detailed Description

LinkedHashMap is a variant of HashMap. Its entries are kept in a doubly-linked list. The iteration order is, by default, the order in which keys were inserted. Reinserting an already existing key doesn't change the order. A key is existing if a call to

containsKey

would return true.

If the three argument constructor is used, and

order

is specified as

true

, the iteration will be in the order that entries were accessed. The access order gets affected by put(), get(), putAll() operations, but not by operations on the collection views.

Null elements are allowed, and all the optional map operations are supported.

Note: The implementation of

LinkedHashMap

is not synchronized. If one thread of several threads accessing an instance modifies the map structurally, access to the map needs to be synchronized. For insertion-ordered instances a structural modification is an operation that removes or adds an entry. Access-ordered instances also are structurally modified by put(), get() and putAll() since these methods change the order of the entries. Changes in the value of an entry are not structural changes.

The Iterator that can be created by calling the

iterator

method throws a

ConcurrentModificationException

if the map is structurally changed while an iterator is used to iterate over the elements. Only the

remove

method that is provided by the iterator allows for removal of elements during iteration. It is not possible to guarantee that this mechanism works in all cases of unsynchronized concurrent modification. It should only be used for debugging purposes.

Since: 1.4

Constructor & Destructor Documentation

◆ LinkedHashMap() [1/5]

java.util.LinkedHashMap< K, V >.LinkedHashMap ( )

inline

Constructs a new empty

LinkedHashMap

instance.

◆ LinkedHashMap() [2/5]

java.util.LinkedHashMap< K, V >.LinkedHashMap ( int s )

inline

Constructs a new

LinkedHashMap

instance with the specified capacity.

Parameters

s	the initial capacity of this map.

Exceptions

IllegalArgumentException if the capacity is less than zero.

◆ LinkedHashMap() [3/5]

java.util.LinkedHashMap< K, V >.LinkedHashMap	(	int	s,
		float	lf
	)

inline

Constructs a new

LinkedHashMap

instance with the specified capacity and load factor.

Parameters

s	the initial capacity of this map.
lf	the initial load factor.

Exceptions

IllegalArgumentException when the capacity is less than zero or the load factor is less or equal to zero.

◆ LinkedHashMap() [4/5]

java.util.LinkedHashMap< K, V >.LinkedHashMap	(	int	s,
		float	lf,
		boolean	order
	)

inline

Constructs a new

LinkedHashMap

instance with the specified capacity, load factor and a flag specifying the ordering behavior.

Parameters

s	the initial capacity of this hash map.
lf	the initial load factor.
order	true if the ordering should be done based on the last access (from least-recently accessed to most-recently accessed), and false if the ordering should be the order in which the entries were inserted.

Exceptions

IllegalArgumentException when the capacity is less than zero or the load factor is less or equal to zero.

◆ LinkedHashMap() [5/5]

java.util.LinkedHashMap< K, V >.LinkedHashMap ( Map<? extends K, ? extends V > m )

inline

Constructs a new

LinkedHashMap

instance containing the mappings from the specified map. The order of the elements is preserved.

Parameters

m	the mappings to add.

Member Function Documentation

◆ clear()

void java.util.LinkedHashMap< K, V >.clear ( )

inline

Removes all elements from this map, leaving it empty.

See also: isEmpty(); size()

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

◆ containsValue()

boolean java.util.LinkedHashMap< K, V >.containsValue ( Object value )

inline

Returns whether this

Map

contains the specified value.

Parameters

value the value to search for.

Returns: true
if this map contains the specified value,
false
otherwise.

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

◆ entrySet()

Set<Map.Entry<K, V> > java.util.LinkedHashMap< K, V >.entrySet ( )

inline

Returns a set containing all of the mappings in this map. Each mapping is an instance of Map.Entry. As the set is backed by this map, changes in one will be reflected in the other.

Returns: a set of the mappings.

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

◆ get()

V java.util.LinkedHashMap< K, V >.get ( Object key )

inline

Returns the value of the mapping with the specified key.

Parameters

key the key.

Returns: the value of the mapping with the specified key, or
null
if no mapping for the specified key is found.

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

◆ keySet()

Set<K> java.util.LinkedHashMap< K, V >.keySet ( )

inline

Returns a set of the keys contained in this map. The set is backed by this map so changes to one are reflected by the other. The set does not support adding.

Returns: a set of the keys.

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

◆ put()

V java.util.LinkedHashMap< K, V >.put	(	K	key,
		V	value
	)

inline

Maps the specified key to the specified value.

Parameters

key	the key.
value	the value.

Returns: the value of any previous mapping with the specified key or
null
if there was no such mapping.

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

◆ remove()

V java.util.LinkedHashMap< K, V >.remove ( Object key )

inline

Removes the mapping with the specified key from this map.

Parameters

key	the key of the mapping to remove.

Returns: the value of the removed mapping or
null
if no mapping for the specified key was found.

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

◆ removeEldestEntry()

boolean java.util.LinkedHashMap< K, V >.removeEldestEntry ( Map.Entry< K, V > eldest )

inlineprotected

This method is queried from the put and putAll methods to check if the eldest member of the map should be deleted before adding the new member. If this map was created with accessOrder = true, then the result of removeEldestEntry is assumed to be false.

Parameters

eldest the entry to check if it should be removed.

Returns: true
if the eldest member should be removed.

◆ values()

Collection<V> java.util.LinkedHashMap< K, V >.values ( )

inline

Returns a collection of the values contained in this map. The collection is backed by this map so changes to one are reflected by the other. The collection supports remove, removeAll, retainAll and clear operations, and it does not support add or addAll operations.

This method returns a collection which is the subclass of AbstractCollection. The iterator method of this subclass returns a "wrapper object" over the iterator of map's entrySet(). The size method wraps the map's size method and the contains method wraps the map's containsValue method.

The collection is created when this method is called for the first time and returned in response to all subsequent calls. This method may return different collections when multiple concurrent calls occur, since no synchronization is performed.

Returns: a collection of the values contained in this map.

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

The documentation for this class was generated from the following file:

src/java/util/LinkedHashMap.java

Classes

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ LinkedHashMap() [1/5]

◆ LinkedHashMap() [2/5]

◆ LinkedHashMap() [3/5]

◆ LinkedHashMap() [4/5]

◆ LinkedHashMap() [5/5]

Member Function Documentation

◆ clear()

◆ containsValue()

◆ entrySet()

◆ get()

◆ keySet()

◆ put()

◆ remove()

◆ removeEldestEntry()

◆ values()