Class AbstractMap.SimpleEntry<K,V>

java.lang.Object
java.util.AbstractMap.SimpleEntry<K,V>
Type Parameters:
K - the type of key
V - the type of the value
All Implemented Interfaces:
Serializable,Map.Entry<K,V>
Enclosing class:
AbstractMap<K,V>
public static classAbstractMap.SimpleEntry<K,V>extendsObjectimplementsMap.Entry<K,V>,Serializable
An Entry maintaining a key and a value. The value may be changed using thesetValue method. Instances of this class are not associated with any map nor with any map's entry-set view.
API Note:
This class facilitates the process of building custom map implementations. For example, it may be convenient to return arrays ofSimpleEntry instances in methodMap.entrySet().toArray.
Since:
1.6
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    SimpleEntry(Map.Entry<? extendsK, ? extendsV> 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
    Compares the specified object with this entry for equality.
    Returns the key corresponding to this entry.
    Returns the value corresponding to this entry.
    int
    Returns the hash code value for this map entry.
    setValue(V value)
    Replaces the value corresponding to this entry with the specified value.
    Returns a String representation of this map entry.

    Methods declared in class java.lang.Object

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

  • Constructor Details

    • 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<? extendsK, ? extendsV> entry)
      Creates an entry representing the same mapping as the specified entry.
      Parameters:
      entry - the entry to copy

  • Method Details

    • 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.
      Specified by:
      setValue in interface Map.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. Returnstrue if the given object is also a map entry and the two entries represent the same mapping. More formally, two entriese1 ande2 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 theequals method works properly across different implementations of theMap.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

      public int hashCode()
      Returns the hash code value for this map entry. The hash code of a map entrye is defined to be:
         (e.getKey()==null   ? 0 : e.getKey().hashCode()) ^   (e.getValue()==null ? 0 : e.getValue().hashCode())
      This ensures thate1.equals(e2) implies thate1.hashCode()==e2.hashCode() for any two Entriese1 ande2, as required by the general contract ofObject.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:

    • 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