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Class AbstractMap.SimpleImmutableEntry<K,V>
- Type Parameters:
K
- the type of the keysV
- the type of the value
- All Implemented Interfaces:
Serializable
,Map.Entry<K,
V>
- Enclosing class:
-
AbstractMap<K,
V>
public static class AbstractMap.SimpleImmutableEntry<K,V> extends Object implements Map.Entry<K,V>, Serializable
setValue
method. Instances of this class are not associated with any map nor with any map's entry-set view.
- API Note:
-
Instances of this class are not necessarily immutable, as the key and value may be mutable. An instance of this specific class is unmodifiable, because the key and value references cannot be changed. A reference of this type may not be unmodifiable, as a subclass may be modifiable or may provide the appearance of modifiability.
This class may be convenient in methods that return thread-safe snapshots of key-value mappings. For alternatives, see the
Map::entry
andMap.Entry::copyOf
methods. - Since:
- 1.6
- See Also:
Constructor Summary
Constructor | Description |
---|---|
SimpleImmutableEntry |
Creates an entry representing the same mapping as the specified entry.
|
SimpleImmutableEntry |
Creates an entry representing a mapping from the specified key to the specified value.
|
Method Summary
Modifier and Type | Method | Description |
---|---|---|
boolean |
equals |
Compares the specified object with this entry for equality.
|
K |
getKey() |
Returns the key corresponding to this entry.
|
V |
getValue() |
Returns the value corresponding to this entry.
|
int |
hashCode() |
Returns the hash code value for this map entry.
|
V |
setValue |
Replaces the value corresponding to this entry with the specified value (optional operation).
|
String |
toString() |
Returns a String representation of this map entry.
|
Constructor Details
SimpleImmutableEntry
public SimpleImmutableEntry(K key, V value)
- Parameters:
key
- the key represented by this entryvalue
- the value represented by this entry
SimpleImmutableEntry
public SimpleImmutableEntry(Map.Entry<? extends K,? extends V> entry)
- Parameters:
entry
- the entry to copy
Method Details
getKey
public K getKey()
getValue
public V getValue()
setValue
public V setValue(V value)
UnsupportedOperationException
, as this class implements an unmodifiable map entry.
- Specified by:
setValue
in interfaceMap.Entry<K,
V> - Implementation Requirements:
-
The implementation in this class always throws
UnsupportedOperationException
. - Parameters:
value
- new value to be stored in this entry- Returns:
- (Does not return)
- Throws:
UnsupportedOperationException
- always
equals
public boolean equals(Object o)
true
if the given object is also a map entry and the two entries represent the same mapping. More formally, two entries e1
and e2
represent the same mapping if
(e1.getKey()==null ?
e2.getKey()==null :
e1.getKey().equals(e2.getKey()))
&&
(e1.getValue()==null ?
e2.getValue()==null :
e1.getValue().equals(e2.getValue()))
This ensures that the equals
method works properly across different implementations of the Map.Entry
interface.
hashCode
public int hashCode()
e
is defined to be:
(e.getKey()==null ? 0 : e.getKey().hashCode()) ^
(e.getValue()==null ? 0 : e.getValue().hashCode())
This ensures that e1.equals(e2)
implies that e1.hashCode()==e2.hashCode()
for any two Entries e1
and e2
, as required by the general contract of Object.hashCode()
.
toString
public String toString()
=
") followed by the string representation of this entry's value.
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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/AbstractMap.SimpleImmutableEntry.html