public static class Object2ObjectMaps.Singleton<K,V> extends Object2ObjectFunctions.Singleton<K,V> implements Object2ObjectMap<K,V>, Serializable, Cloneable
This class may be useful to implement your own in case you subclass a type-specific map.
Object2ObjectMap.Entry<K,V>, Object2ObjectMap.FastEntrySet<K,V>| Modifier and Type | Method and Description |
|---|---|
boolean |
containsValue(Object v)
Returns true if this map maps one or more keys to the
specified value.
|
ObjectSet<Map.Entry<K,V>> |
entrySet()
Returns a set view of the mappings contained in this map.
|
boolean |
equals(Object o)
Indicates whether some other object is "equal to" this one.
|
int |
hashCode()
Returns a hash code value for the object.
|
boolean |
isEmpty()
Returns true if this map contains no key-value mappings.
|
ObjectSet<K> |
keySet()
Returns a
Set view of the keys contained in this map. |
ObjectSet<Object2ObjectMap.Entry<K,V>> |
object2ObjectEntrySet()
Returns a type-specific set view of the mappings contained in this map.
|
void |
putAll(Map<? extends K,? extends V> m)
Copies all of the mappings from the specified map to this map
(optional operation).
|
String |
toString()
Returns a string representation of the object.
|
ObjectCollection<V> |
values()
Returns a
Collection view of the values contained in this map. |
clone, containsKey, get, sizedefaultReturnValue, defaultReturnValueclear, containsKey, defaultReturnValue, defaultReturnValue, put, remove, sizegetcompute, computeIfAbsent, computeIfPresent, forEach, get, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAllpublic boolean containsValue(Object v)
java.util.MapcontainsValue in interface Map<K,V>v - value whose presence in this map is to be testedpublic void putAll(Map<? extends K,? extends V> m)
java.util.Mapput(k, v) on this map once
for each mapping from key k to value v in the
specified map. The behavior of this operation is undefined if the
specified map is modified while the operation is in progress.public ObjectSet<Object2ObjectMap.Entry<K,V>> object2ObjectEntrySet()
Object2ObjectMap
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).
object2ObjectEntrySet in interface Object2ObjectMap<K,V>Map.entrySet()public ObjectSet<Map.Entry<K,V>> entrySet()
Note that this specification strengthens the one given in
Map.entrySet().
entrySet in interface Object2ObjectMap<K,V>entrySet in interface Map<K,V>Map.entrySet()public ObjectSet<K> keySet()
Object2ObjectMapSet view of the keys contained in this map.
The set is backed by the map, so changes to the map are
reflected in the set, and vice-versa. If the map is modified
while an iteration over the set is in progress (except through
the iterator's own remove operation), the results of
the iteration are undefined. The set supports element removal,
which removes the corresponding mapping from the map, via the
Iterator.remove, Set.remove,
removeAll, retainAll, and clear
operations. It does not support the add or addAll
operations.
Note that this specification strengthens the one given in
Map.keySet().
keySet in interface Object2ObjectMap<K,V>keySet in interface Map<K,V>Map.keySet()public ObjectCollection<V> values()
Object2ObjectMapCollection view of the values contained in this map.
The collection is backed by the map, so changes to the map are
reflected in the collection, and vice-versa. If the map is
modified while an iteration over the collection is in progress
(except through the iterator's own remove operation),
the results of the iteration are undefined. The collection
supports element removal, which removes the corresponding
mapping from the map, via the Iterator.remove,
Collection.remove, removeAll,
retainAll and clear operations. It does not
support the add or addAll operations.
Note that this specification strengthens the one given in
Map.values().
values in interface Object2ObjectMap<K,V>values in interface Map<K,V>Map.values()public boolean isEmpty()
java.util.Mappublic int hashCode()
java.lang.ObjectHashMap.
The general contract of hashCode is:
hashCode method
must consistently return the same integer, provided no information
used in equals comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode method on each of
the two objects must produce the same integer result.
Object.equals(java.lang.Object)
method, then calling the hashCode method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
Java™ programming language.)
hashCode in interface Map<K,V>hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public boolean equals(Object o)
java.lang.Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
x and y, multiple invocations of
x.equals(y) consistently return true
or consistently return false, provided no
information used in equals comparisons on the
objects is modified.
x,
x.equals(null) should return false.
The equals method for class Object implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x and
y, this method returns true if and only
if x and y refer to the same object
(x == y has the value true).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
public String toString()
java.lang.ObjecttoString method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())