Class AbstractMap.SimpleEntry<K,V>
- java.lang.Object
-
- java.util.AbstractMap.SimpleEntry<K,V>
- All Implemented Interfaces:
-
Serializable
,Map.Entry<K,V>
- Enclosing class:
- AbstractMap<K,V>
public static class AbstractMap.SimpleEntry<K,V> extends Object implements Map.Entry<K,V>, Serializable
An Entry maintaining a key and a value. The value may be changed using the setValue
method. This class facilitates the process of building custom map implementations. For example, it may be convenient to return arrays of SimpleEntry
instances in method Map.entrySet().toArray
.
- Since:
- 1.6
- See Also:
- Serialized Form
Constructor Summary
Constructor | Description |
---|---|
SimpleEntry(Map.Entry<? extends K,? extends V> entry) | Creates an entry representing the same mapping as the specified entry. |
SimpleEntry(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. |
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
SimpleEntry
public SimpleEntry(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
SimpleEntry
public SimpleEntry(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.
- Specified by:
-
setValue
in interfaceMap.Entry<K,V>
- Parameters:
-
value
- new value to be stored in this entry - Returns:
- the old value corresponding to the entry
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.