Module lettuce.core

Package io.lettuce.core

Class KeyValue<K,V>

java.lang.Object

io.lettuce.core.Value<V>

io.lettuce.core.KeyValue<K,V>

Type Parameters:

K - Key type.

V - Value type.

All Implemented Interfaces:

Serializable

public class KeyValue<K,V>
extends Value<V>

A key-value container extension to Value. A KeyValue requires always a non-null key on construction.

Author:

Will Glozer, Mark Paluch

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	KeyValue()	Serializable constructor.

Method Summary

Modifier and Type	Method	Description
static <K, V> KeyValue<K,V>	empty(K key)	Returns an empty KeyValue instance with the key set.
boolean	equals(Object o)
static <K, T extends V, V> KeyValue<K,V>	from(K key, Optional<T> optional)	Creates a KeyValue from a key and an Optional.
static <K, T extends V, V> KeyValue<K,V>	fromNullable(K key, T value)	Creates a KeyValue from a key andvalue.
K	getKey()
int	hashCode()
static <K, T extends V, V> KeyValue<K,V>	just(K key, T value)	Creates a KeyValue from a key and value.
<R> KeyValue<K,R>	map(Function<? super V,? extends R> mapper)	Returns a KeyValue consisting of the results of applying the given function to the value of this element.
String	toString()

Methods inherited from class io.lettuce.core.Value

empty, from, fromNullable, getValue, getValueOrElse, getValueOrElseGet, getValueOrElseThrow, hasValue, ifEmpty, ifHasValue, ifHasValueOrElse, isEmpty, just, optional, stream

Methods inherited from class java.lang.Object

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

Constructor Details

KeyValue

protected KeyValue()

Serializable constructor.

Method Details

from

public static <K,
T extends V,
V> KeyValue<K,V> from(K key,
Optional<T> optional)

Creates a KeyValue from a key and an Optional. The resulting value contains the value from the Optional if a value is present. Value is empty if the Optional is empty.

Parameters:

key - the key, must not be null.

optional - the optional. May be empty but never null.

Returns:

the KeyValue

fromNullable

public static <K,
T extends V,
V> KeyValue<K,V> fromNullable(K key,
T value)

Creates a KeyValue from a key andvalue. The resulting value contains the value if the value is not null.

Parameters:

key - the key, must not be null.

value - the value. May be null.

Returns:

the KeyValue

empty

public static <K,
V> KeyValue<K,V> empty(K key)

Returns an empty KeyValue instance with the key set. No value is present for this instance.

Parameters:

key - the key, must not be null.

Returns:

the KeyValue

just

public static <K,
T extends V,
V> KeyValue<K,V> just(K key,
T value)

Creates a KeyValue from a key and value. The resulting value contains the value.

Parameters:

key - the key. Must not be null.

value - the value. Must not be null.

Returns:

the KeyValue

equals

public boolean equals(Object o)

Overrides:

equals in class Value<V>

hashCode

public int hashCode()

Overrides:

hashCode in class Value<V>

toString

public String toString()

Overrides:

toString in class Value<V>

getKey

public K getKey()

Returns:

the key

map

public <R> KeyValue<K,R> map(Function<? super V,? extends R> mapper)

Returns a KeyValue consisting of the results of applying the given function to the value of this element. Mapping is performed only if a value is present.

Overrides:

map in class Value<V>

Type Parameters:

R - The element type of the new KeyValue

Parameters:

mapper - a stateless function to apply to each element

Returns:

the new KeyValue