Java compact1, compact2, compact3 java.util Class AbstractMap.SimpleImmutableEntry<K,V>（JDK8）

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.

  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