AbstractMap.SimpleEntry (Java Platform SE 8 ) (original) (raw)

• 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

  Constructors

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

  • Method Summary

  All Methods Instance Methods Concrete Methods

  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 inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang")  
     `[clone](../../java/lang/Object.html#clone--), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`  
     * ### Methods inherited from interface java.util.[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")  
     `[comparingByKey](../../java/util/Map.Entry.html#comparingByKey--), [comparingByKey](../../java/util/Map.Entry.html#comparingByKey-java.util.Comparator-), [comparingByValue](../../java/util/Map.Entry.html#comparingByValue--), [comparingByValue](../../java/util/Map.Entry.html#comparingByValue-java.util.Comparator-)`

• • Constructor Detail

     * #### SimpleEntry  
     public SimpleEntry([K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") key,  
                        [V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") 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](../../java/util/Map.Entry.html "interface in java.util")<? extends [K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),? extends [V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")> entry)  
     Creates an entry representing the same mapping as the specified entry.  
     Parameters:  
     `entry` \- the entry to copy  

  • Method Detail

    * #### getKey  
    public [K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") getKey()  
    Returns the key corresponding to this entry.  
    Specified by:  
    `[getKey](../../java/util/Map.Entry.html#getKey--)` in interface `[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")<[K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),[V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")>`  
    Returns:  
    the key corresponding to this entry  
    * #### getValue  
    public [V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") getValue()  
    Returns the value corresponding to this entry.  
    Specified by:  
    `[getValue](../../java/util/Map.Entry.html#getValue--)` in interface `[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")<[K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),[V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")>`  
    Returns:  
    the value corresponding to this entry  
    * #### setValue  
    public [V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") setValue([V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry") value)  
    Replaces the value corresponding to this entry with the specified value.  
    Specified by:  
    `[setValue](../../java/util/Map.Entry.html#setValue-V-)` in interface `[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")<[K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),[V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")>`  
    Parameters:  
    `value` \- new value to be stored in this entry  
    Returns:  
    the old value corresponding to the entry  
    * #### equals  
    public boolean equals([Object](../../java/lang/Object.html "class in java.lang") 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](../../java/util/Map.Entry.html#equals-java.lang.Object-)` in interface `[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")<[K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),[V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")>`  
    Overrides:  
    `[equals](../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
    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()](../../java/util/AbstractMap.SimpleEntry.html#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()](../../java/lang/Object.html#hashCode--).  
    Specified by:  
    `[hashCode](../../java/util/Map.Entry.html#hashCode--)` in interface `[Map.Entry](../../java/util/Map.Entry.html "interface in java.util")<[K](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry"),[V](../../java/util/AbstractMap.SimpleEntry.html "type parameter in AbstractMap.SimpleEntry")>`  
    Overrides:  
    `[hashCode](../../java/lang/Object.html#hashCode--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
    Returns:  
    the hash code value for this map entry  
    See Also:  
    [equals(java.lang.Object)](../../java/util/AbstractMap.SimpleEntry.html#equals-java.lang.Object-)  
    * #### toString  
    public [String](../../java/lang/String.html "class in java.lang") 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](../../java/lang/Object.html#toString--)` in class `[Object](../../java/lang/Object.html "class in java.lang")`  
    Returns:  
    a String representation of this map entry

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