public class Reference2ReferenceLinkedOpenHashMap<K,V> extends AbstractReference2ReferenceSortedMap<K,V> implements java.io.Serializable, java.lang.Cloneable, Hash
Instances of this class use a hash table to represent a map. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create maps with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.
Note that clear() does not modify the hash table size. Rather, a
family of trimming methods lets you control the size of
the table; this is particularly useful if you reuse instances of this class.
Iterators generated by this map will enumerate pairs in the same order in which they have been added to the map (addition of pairs whose key is already present in the map does not change the iteration order). Note that this order has nothing in common with the natural order of the keys. The order is kept by means of a doubly linked list, represented via an array of longs parallel to the table.
This class implements the interface of a sorted map, so to allow easy access
of the iteration order: for instance, you can get the first key in iteration
order with firstKey() without having to create an iterator; however,
this class partially violates the SortedMap contract
because all submap methods throw an exception and comparator()
returns always null.
Additional methods, such as getAndMoveToFirst(), make it easy to use
instances of this class as a cache (e.g., with LRU policy).
The iterators provided by the views of this class using are type-specific
list iterators, and can be started at any
element which is a key of the map, or a
NoSuchElementException exception will be thrown. If, however, the
provided element is not the first or last key in the map, the first access to
the list index will require linear time, as in the worst case the entire key
set must be scanned in iteration order to retrieve the positional index of
the starting key. If you use just the methods of a type-specific
BidirectionalIterator, however, all operations
will be performed in constant time.
Hash,
HashCommon,
Serialized FormAbstractReference2ReferenceMap.BasicEntry<K,V>, AbstractReference2ReferenceMap.BasicEntrySet<K,V>Hash.Strategy<K>Reference2ReferenceSortedMap.FastSortedEntrySet<K,V>Reference2ReferenceMap.Entry<K,V>, Reference2ReferenceMap.FastEntrySet<K,V>DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR| Constructor and Description |
|---|
Reference2ReferenceLinkedOpenHashMap()
Creates a new hash map with initial expected
Hash.DEFAULT_INITIAL_SIZE entries and
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ReferenceLinkedOpenHashMap(int expected)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor. |
Reference2ReferenceLinkedOpenHashMap(int expected,
float f)
Creates a new hash map.
|
Reference2ReferenceLinkedOpenHashMap(K[] k,
V[] v)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor
using the elements of two parallel arrays. |
Reference2ReferenceLinkedOpenHashMap(K[] k,
V[] v,
float f)
Creates a new hash map using the elements of two parallel arrays.
|
Reference2ReferenceLinkedOpenHashMap(java.util.Map<? extends K,? extends V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given one. |
Reference2ReferenceLinkedOpenHashMap(java.util.Map<? extends K,? extends V> m,
float f)
Creates a new hash map copying a given one.
|
Reference2ReferenceLinkedOpenHashMap(Reference2ReferenceMap<K,V> m)
Creates a new hash map with
Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given type-specific one. |
Reference2ReferenceLinkedOpenHashMap(Reference2ReferenceMap<K,V> m,
float f)
Creates a new hash map copying a given type-specific one.
|
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Removes all of the mappings from this map (optional operation).
|
Reference2ReferenceLinkedOpenHashMap<K,V> |
clone()
Returns a deep copy of this map.
|
java.util.Comparator<? super K> |
comparator()
Returns the comparator associated with this sorted set, or null if it uses
its keys' natural ordering.
|
boolean |
containsKey(java.lang.Object k)
Returns true if this function contains a mapping for the specified key.
|
boolean |
containsValue(java.lang.Object v) |
K |
firstKey()
Returns the first key of this map in iteration order.
|
V |
get(java.lang.Object k)
Returns the value to which the given key is mapped.
|
V |
getAndMoveToFirst(K k)
Returns the value to which the given key is mapped; if the key is present, it
is moved to the first position of the iteration order.
|
V |
getAndMoveToLast(K k)
Returns the value to which the given key is mapped; if the key is present, it
is moved to the last position of the iteration order.
|
int |
hashCode()
Returns a hash code for this map.
|
Reference2ReferenceSortedMap<K,V> |
headMap(K to)
Returns a view of the portion of this sorted map whose keys are strictly less
than
toKey. |
boolean |
isEmpty() |
ReferenceSortedSet<K> |
keySet()
Returns a type-specific-set view of the keys of this map.
|
K |
lastKey()
Returns the last key of this map in iteration order.
|
V |
put(K k,
V v)
Adds a pair to the map (optional operation).
|
void |
putAll(java.util.Map<? extends K,? extends V> m) |
V |
putAndMoveToFirst(K k,
V v)
Adds a pair to the map; if the key is already present, it is moved to the
first position of the iteration order.
|
V |
putAndMoveToLast(K k,
V v)
Adds a pair to the map; if the key is already present, it is moved to the
last position of the iteration order.
|
Reference2ReferenceSortedMap.FastSortedEntrySet<K,V> |
reference2ReferenceEntrySet()
Returns a type-specific sorted-set view of the mappings contained in this
map.
|
V |
remove(java.lang.Object k)
Removes the mapping with the given key (optional operation).
|
V |
removeFirst()
Removes the mapping associated with the first key in iteration order.
|
V |
removeLast()
Removes the mapping associated with the last key in iteration order.
|
int |
size()
Returns the number of key/value mappings in this map.
|
Reference2ReferenceSortedMap<K,V> |
subMap(K from,
K to)
Returns a view of the portion of this sorted map whose keys range from
fromKey, inclusive, to toKey, exclusive. |
Reference2ReferenceSortedMap<K,V> |
tailMap(K from)
Returns a view of the portion of this sorted map whose keys are greater than
or equal to
fromKey. |
boolean |
trim()
Rehashes the map, making the table as small as possible.
|
boolean |
trim(int n)
Rehashes this map if the table is too large.
|
ReferenceCollection<V> |
values()
Returns a type-specific-set view of the values of this map.
|
equals, toStringdefaultReturnValue, defaultReturnValueentrySetdefaultReturnValue, defaultReturnValuepublic Reference2ReferenceLinkedOpenHashMap(int expected,
float f)
The actual table size will be the least power of two greater than
expected/f.
expected - the expected number of elements in the hash map.f - the load factor.public Reference2ReferenceLinkedOpenHashMap(int expected)
Hash.DEFAULT_LOAD_FACTOR as load factor.expected - the expected number of elements in the hash map.public Reference2ReferenceLinkedOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE entries and
Hash.DEFAULT_LOAD_FACTOR as load factor.public Reference2ReferenceLinkedOpenHashMap(java.util.Map<? extends K,? extends V> m, float f)
m - a Map to be copied into the new hash map.f - the load factor.public Reference2ReferenceLinkedOpenHashMap(java.util.Map<? extends K,? extends V> m)
Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given one.m - a Map to be copied into the new hash map.public Reference2ReferenceLinkedOpenHashMap(Reference2ReferenceMap<K,V> m, float f)
m - a type-specific map to be copied into the new hash map.f - the load factor.public Reference2ReferenceLinkedOpenHashMap(Reference2ReferenceMap<K,V> m)
Hash.DEFAULT_LOAD_FACTOR as load factor
copying a given type-specific one.m - a type-specific map to be copied into the new hash map.public Reference2ReferenceLinkedOpenHashMap(K[] k, V[] v, float f)
k - the array of keys of the new hash map.v - the array of corresponding values in the new hash map.f - the load factor.java.lang.IllegalArgumentException - if k and v have different lengths.public Reference2ReferenceLinkedOpenHashMap(K[] k, V[] v)
Hash.DEFAULT_LOAD_FACTOR as load factor
using the elements of two parallel arrays.k - the array of keys of the new hash map.v - the array of corresponding values in the new hash map.java.lang.IllegalArgumentException - if k and v have different lengths.public void putAll(java.util.Map<? extends K,? extends V> m)
AbstractReference2ReferenceMappublic V put(K k, V v)
Reference2ReferenceFunctionput in interface Reference2ReferenceFunction<K,V>put in interface Reference2ReferenceMap<K,V>put in interface java.util.Map<K,V>k - the key.v - the value.Function.put(Object,Object)public V remove(java.lang.Object k)
Reference2ReferenceFunctionremove in interface Reference2ReferenceFunction<K,V>remove in interface Reference2ReferenceMap<K,V>remove in interface java.util.Map<K,V>k - the key.Function.remove(Object)public V removeFirst()
java.util.NoSuchElementException - is this map is empty.public V removeLast()
java.util.NoSuchElementException - is this map is empty.public V getAndMoveToFirst(K k)
k - the key.public V getAndMoveToLast(K k)
k - the key.public V putAndMoveToFirst(K k, V v)
k - the key.v - the value.public V putAndMoveToLast(K k, V v)
k - the key.v - the value.public V get(java.lang.Object k)
Reference2ReferenceFunctionget in interface Reference2ReferenceFunction<K,V>get in interface java.util.Map<K,V>k - the key.Function.get(Object)public boolean containsKey(java.lang.Object k)
Reference2ReferenceMapcontainsKey in interface Reference2ReferenceMap<K,V>containsKey in interface java.util.Map<K,V>containsKey in class AbstractReference2ReferenceMap<K,V>k - the key.key.Map.containsKey(Object)public boolean containsValue(java.lang.Object v)
containsValue in interface java.util.Map<K,V>containsValue in class AbstractReference2ReferenceMap<K,V>public void clear()
Reference2ReferenceMappublic int size()
Reference2ReferenceMapInteger.MAX_VALUE elements, returns
Integer.MAX_VALUE.public boolean isEmpty()
public K firstKey()
public K lastKey()
public Reference2ReferenceSortedMap<K,V> tailMap(K from)
fromKey.
Note that this specification strengthens the one given in
SortedMap.tailMap(Object).
This implementation just throws an UnsupportedOperationException.
public Reference2ReferenceSortedMap<K,V> headMap(K to)
toKey.
Note that this specification strengthens the one given in
SortedMap.headMap(Object).
This implementation just throws an UnsupportedOperationException.
public Reference2ReferenceSortedMap<K,V> subMap(K from, K to)
fromKey, inclusive, to toKey, exclusive.
Note that this specification strengthens the one given in
SortedMap.subMap(Object,Object).
This implementation just throws an UnsupportedOperationException.
public java.util.Comparator<? super K> comparator()
Note that this specification strengthens the one given in
SortedMap.comparator().
This implementation just returns null.
comparator in interface Reference2ReferenceSortedMap<K,V>comparator in interface java.util.SortedMap<K,V>SortedMap.comparator()public Reference2ReferenceSortedMap.FastSortedEntrySet<K,V> reference2ReferenceEntrySet()
Reference2ReferenceSortedMapNote that this specification strengthens the one given in the corresponding type-specific unsorted map.
reference2ReferenceEntrySet in interface Reference2ReferenceMap<K,V>reference2ReferenceEntrySet in interface Reference2ReferenceSortedMap<K,V>Reference2ReferenceSortedMap.entrySet()public ReferenceSortedSet<K> keySet()
AbstractReference2ReferenceSortedMap
The view is backed by the set returned by Map.entrySet(). Note that
no attempt is made at caching the result of this method, as this
would require adding some attributes that lightweight implementations would
not need. Subclasses may easily override this policy by calling this method
and caching the result, but implementors are encouraged to write more
efficient ad-hoc implementations.
The view is backed by the sorted set returned by
Map.entrySet(). Note that no attempt is made at caching
the result of this method, as this would require adding some attributes
that lightweight implementations would not need. Subclasses may easily
override this policy by calling this method and caching the result, but
implementors are encouraged to write more efficient ad-hoc implementations.
keySet in interface Reference2ReferenceMap<K,V>keySet in interface Reference2ReferenceSortedMap<K,V>keySet in interface java.util.Map<K,V>keySet in interface java.util.SortedMap<K,V>keySet in class AbstractReference2ReferenceSortedMap<K,V>Map.keySet()public ReferenceCollection<V> values()
AbstractReference2ReferenceSortedMap
The view is backed by the set returned by Map.entrySet(). Note that
no attempt is made at caching the result of this method, as this
would require adding some attributes that lightweight implementations would
not need. Subclasses may easily override this policy by calling this method
and caching the result, but implementors are encouraged to write more
efficient ad-hoc implementations.
The view is backed by the sorted set returned by
Map.entrySet(). Note that no attempt is made at caching
the result of this method, as this would require adding some attributes
that lightweight implementations would not need. Subclasses may easily
override this policy by calling this method and caching the result, but
implementors are encouraged to write more efficient ad-hoc implementations.
values in interface Reference2ReferenceMap<K,V>values in interface Reference2ReferenceSortedMap<K,V>values in interface java.util.Map<K,V>values in interface java.util.SortedMap<K,V>values in class AbstractReference2ReferenceSortedMap<K,V>Map.values()public boolean trim()
This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.
If the table size is already the minimum possible, this method does nothing.
trim(int)public boolean trim(int n)
Let N be the smallest table size that can hold
max(n, entries, still satisfying the load
factor. If the current table size is smaller than or equal to N,
this method does nothing. Otherwise, it rehashes this map in a table of size
N.
size())
This method is useful when reusing maps. Clearing a map leaves the table size untouched. If you are reusing a map many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient maps.
n - the threshold for the trimming.trim()public Reference2ReferenceLinkedOpenHashMap<K,V> clone()
This method performs a deep copy of this hash map; the data stored in the map, however, is not cloned. Note that this makes a difference only for object keys.
clone in class java.lang.Objectpublic int hashCode()
equals() is not overriden, it is important that the value returned by
this method is the same value as the one returned by the overriden method.