Class AbstractMap.SimpleImmutableEntry<K,V>
- java.lang.Object
-
- java.util.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
Constructor Summary
Constructor | Description |
---|---|
SimpleImmutableEntry(Map.Entry<? extends K,? extends V> entry) | Creates an entry representing the same mapping as the specified entry. |
SimpleImmutableEntry(K key,
V value) | Creates an entry representing a mapping from the specified key to the specified value. |
Method Summary
Modifier and Type | Method | 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 declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Constructor Detail
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
Method Detail
getKey
public K getKey()
Returns the key corresponding to this entry.
getValue
public V getValue()
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 interfaceMap.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 interfaceMap.Entry<K,V>
- Overrides:
-
equals
in classObject
- 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 interfaceMap.Entry<K,V>
- Overrides:
-
hashCode
in classObject
- 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.