Class AbstractMap.SimpleImmutableEntry<K,V>

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

An Entry maintaining an immutable key and value. This class does not support method setValue. This class may be convenient in methods that return thread-safe snapshots of key-value mappings.

Since:
1.6
See Also:
Serialized Form

Constructors

Constructor and Description
SimpleImmutableEntry(K key, V value)

Creates an entry representing a mapping from the specified key to the specified value.
SimpleImmutableEntry(Map.Entry<? extends K,? extends V> entry)

Creates an entry representing the same mapping as the specified entry.

Methods

Modifier and Type Method and Description
boolean equals(Object o)

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(V value)

Replaces the value corresponding to this entry with the specified value (optional operation).
String toString()

Returns a String representation of this map entry.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map.Entry

comparingByKey, comparingByKey, comparingByValue, comparingByValue

Constructors

SimpleImmutableEntry

public SimpleImmutableEntry(K key,
                            V value)

Creates an entry representing a mapping from the specified key to the specified value.

Parameters:
key - the key represented by this entry
value - the value represented by this entry

SimpleImmutableEntry

public SimpleImmutableEntry(Map.Entry<? extends K,? extends V> entry)

Creates an entry representing the same mapping as the specified entry.

Parameters:
entry - the entry to copy

Methods

getKey

public K getKey()

Returns the key corresponding to this entry.

Specified by:
getKey in interface Map.Entry<K,V>
Returns:
the key corresponding to this entry

getValue

public V getValue()

Returns the value corresponding to this entry.

Specified by:
getValue in interface Map.Entry<K,V>
Returns:
the value corresponding to this entry

setValue

public V setValue(V value)

Replaces the value corresponding to this entry with the specified value (optional operation). This implementation simply throws UnsupportedOperationException, as this class implements an immutable map entry.

Specified by:
setValue in interface Map.Entry<K,V>
Parameters:
value - new value to be stored in this entry
Returns:
(Does not return)
Throws:
UnsupportedOperationException - always

equals

public boolean equals(Object o)

Compares the specified object with this entry for equality. Returns 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.

Specified by:
equals in interface Map.Entry<K,V>
Overrides:
equals in class Object
Parameters:
o - object to be compared for equality with this map entry
Returns:
true if the specified object is equal to this map entry
See Also:
hashCode()

hashCode

public int hashCode()

Returns the hash code value for this map entry. The hash code of a map entry 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().

Specified by:
hashCode in interface Map.Entry<K,V>
Overrides:
hashCode in class Object
Returns:
the hash code value for this map entry
See Also:
equals(java.lang.Object)

toString

public String toString()

Returns a String representation of this map entry. This implementation returns the string representation of this entry's key followed by the equals character ("=") followed by the string representation of this entry's value.

Overrides:
toString in class Object
Returns:
a String representation of this map entry

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/javase/8/docs/api/java/util/AbstractMap.SimpleImmutableEntry.html