public interface Reference2ReferenceMap<K,V> extends Reference2ReferenceFunction<K,V>, java.util.Map<K,V>
Map
; provides some additional methods that use polymorphism to avoid (un)boxing, and handling of a default return value.
Besides extending the corresponding type-specific function, this interface strengthens Map.entrySet()
,
keySet()
and values()
. Moreover, a number of methods, such as size()
, defaultReturnValue()
, etc., are un-defaulted
as their function default do not make sense for a map.
Maps returning entry sets of type Reference2ReferenceMap.FastEntrySet
support also fast iteration.
This interface specifies reference equality semantics (members will be compared equal with
==
instead of equals
) for its keys or values (or both), which may result in breaks in contract
if attempted to be used with non reference-equality semantics based Map
s. For example, a
aReferenceToIntMap.equals(aObjectToIntMap)
may return different a different result then
aObjectToIntMap.equals(aReferenceToIntMap)
, in violation of equals
's
contract requiring it being symmetric.
A submap or subset may or may not have an independent default return value (which however must be initialized to the default return value of the originator).
Map
Modifier and Type | Interface and Description |
---|---|
static interface |
Reference2ReferenceMap.Entry<K,V>
A type-specific
Map.Entry ; provides some additional methods
that use polymorphism to avoid (un)boxing. |
static interface |
Reference2ReferenceMap.FastEntrySet<K,V>
An entry set providing fast iteration.
|
Modifier and Type | Method and Description |
---|---|
default void |
clear()
Removes all of the mappings from this map (optional operation).
|
default V |
compute(K key,
java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
Attempts to compute a mapping for the specified key and its current mapped value (or
null if there is no current mapping). |
default V |
computeIfAbsent(K key,
Reference2ReferenceFunction<? super K,? extends V> mappingFunction)
If the specified key is not already associated with a value, attempts to compute its value
using the given mapping function and enters it into this map, unless the key is not present
in the given mapping function.
|
default V |
computeIfPresent(K key,
java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
|
default V |
computeReferenceIfAbsentPartial(K key,
Reference2ReferenceFunction<? super K,? extends V> mappingFunction)
Deprecated.
Please use
computeIfAbsent() instead. |
boolean |
containsKey(java.lang.Object key)
Returns true if this function contains a mapping for the specified key.
|
V |
defaultReturnValue()
Gets the default return value.
|
void |
defaultReturnValue(V rv)
Sets the default return value (optional operation).
|
default ObjectSet<java.util.Map.Entry<K,V>> |
entrySet()
Returns a set view of the mappings contained in this map.
|
default void |
forEach(java.util.function.BiConsumer<? super K,? super V> consumer) |
default V |
getOrDefault(java.lang.Object key,
V defaultValue)
Returns the value to which the specified key is mapped, or the
defaultValue if this
map contains no mapping for the key. |
ReferenceSet<K> |
keySet() |
default V |
merge(K key,
V value,
java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
If the specified key is not already associated with a value, associates it with the given
value . |
default V |
put(K key,
V value)
Adds a pair to the map (optional operation).
|
default V |
putIfAbsent(K key,
V value)
If the specified key is not already associated with a value, associates it with the given
value and returns the default return value, else returns
the current value.
|
ObjectSet<Reference2ReferenceMap.Entry<K,V>> |
reference2ReferenceEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
default V |
remove(java.lang.Object key)
Removes the mapping with the given key (optional operation).
|
default boolean |
remove(java.lang.Object key,
java.lang.Object value)
Removes the entry for the specified key only if it is currently mapped to the specified value.
|
default V |
replace(K key,
V value)
Replaces the entry for the specified key only if it is currently mapped to some value.
|
default boolean |
replace(K key,
V oldValue,
V newValue)
Replaces the entry for the specified key only if currently mapped to the specified value.
|
int |
size()
Returns the number of key/value mappings in this map.
|
ReferenceCollection<V> |
values() |
andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort, get
int size()
Integer.MAX_VALUE
elements, returns Integer.MAX_VALUE
.default void clear()
void defaultReturnValue(V rv)
get()
,
put()
and remove()
to denote that the map does not contain
the specified key. It must be null
by default.
Warning: Changing this to a non-null value can have
unforeseen consequences. Especially, it breaks compatibility with the
specifications of Java's Map
interface. It has to be
used with great care and thorough study of all method comments is
recommended.
defaultReturnValue
in interface Reference2ReferenceFunction<K,V>
rv
- the new default return value.defaultReturnValue()
V defaultReturnValue()
defaultReturnValue
in interface Reference2ReferenceFunction<K,V>
ObjectSet<Reference2ReferenceMap.Entry<K,V>> reference2ReferenceEntrySet()
This method is necessary because there is no inheritance along
type parameters: it is thus impossible to strengthen Map.entrySet()
so that it returns an ObjectSet
of type-specific entries (the latter makes it possible to
access keys and values with type-specific methods).
Map.entrySet()
default ObjectSet<java.util.Map.Entry<K,V>> entrySet()
default V put(K key, V value)
This default implementation just delegates to the corresponding function method.
put
in interface java.util.Map<K,V>
put
in interface Reference2ReferenceFunction<K,V>
key
- the key.value
- the value.Function.put(Object,Object)
default V remove(java.lang.Object key)
This default implementation just delegates to the corresponding type-specific–function method.
remove
in interface java.util.Map<K,V>
remove
in interface Reference2ReferenceFunction<K,V>
key
- the key.Function.remove(Object)
ReferenceSet<K> keySet()
ReferenceCollection<V> values()
boolean containsKey(java.lang.Object key)
default V getOrDefault(java.lang.Object key, V defaultValue)
defaultValue
if this
map contains no mapping for the key.getOrDefault
in interface java.util.Map<K,V>
getOrDefault
in interface Reference2ReferenceFunction<K,V>
key
- the key.defaultValue
- the default mapping of the key.defaultValue
if this map contains no mapping for the key.Map.getOrDefault(Object, Object)
default V putIfAbsent(K key, V value)
putIfAbsent
in interface java.util.Map<K,V>
key
- key with which the specified value is to be associated.value
- value to be associated with the specified key.Map.putIfAbsent(Object, Object)
default boolean remove(java.lang.Object key, java.lang.Object value)
default boolean replace(K key, V oldValue, V newValue)
replace
in interface java.util.Map<K,V>
key
- key with which the specified value is associated.oldValue
- value expected to be associated with the specified key.newValue
- value to be associated with the specified key.true
if the value was replaced.Map.replace(Object, Object, Object)
default V replace(K key, V value)
replace
in interface java.util.Map<K,V>
key
- key with which the specified value is associated.value
- value to be associated with the specified key.Map.replace(Object, Object)
default V computeIfAbsent(K key, Reference2ReferenceFunction<? super K,? extends V> mappingFunction)
This version of computeIfAbsent()
uses a type-specific version of fastutil
's Function
.
Since Function
has a containsKey()
method, it is possible to avoid adding a key by having containsKey()
return false
for that key.
key
- key with which the specified value is to be associated.mappingFunction
- the function to compute a value.Map.computeIfAbsent(Object, java.util.function.Function)
computeIfAbsent()
methods have a different logic based on the argument;
no delegation is performed, contrarily to other superficially similar
methods such as Iterator.forEachRemaining(java.util.function.Consumer<? super E>)
or List.replaceAll(java.util.function.UnaryOperator<E>)
.@Deprecated default V computeReferenceIfAbsentPartial(K key, Reference2ReferenceFunction<? super K,? extends V> mappingFunction)
computeIfAbsent()
instead.default V computeIfPresent(K key, java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
computeIfPresent
in interface java.util.Map<K,V>
key
- key with which the specified value is to be associated.remappingFunction
- the function to compute a value.Map.computeIfPresent(Object, java.util.function.BiFunction)
default V compute(K key, java.util.function.BiFunction<? super K,? super V,? extends V> remappingFunction)
null
if there is no current mapping).
If the function returns null
, the mapping is removed (or remains absent if initially absent).
If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
compute
in interface java.util.Map<K,V>
key
- key with which the specified value is to be associated.remappingFunction
- the function to compute a value.Map.compute(Object, java.util.function.BiFunction)
default V merge(K key, V value, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
value
.
Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null
.merge
in interface java.util.Map<K,V>
key
- key with which the resulting value is to be associated.value
- the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.remappingFunction
- the function to recompute a value if present.Map.merge(Object, Object, java.util.function.BiFunction)