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 and Description
protected	KeyValue() Serializable constructor.

Method Summary

Modifier and Type	Method and 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, just, optional, stream

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyValue

protected KeyValue()

Serializable constructor.

Method Detail

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.

Type Parameters:

K -

T -

V -

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.

Type Parameters:

K -

T -

V -

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.

Type Parameters:

K -

V -

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.

Type Parameters:

K -

T -

V -

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.