Package org.miaixz.bus.core.center.map.concurrent

Class Weighers

java.lang.Object

org.miaixz.bus.core.center.map.concurrent.Weighers

public final class Weighers
extends Object

A common set of Weigher and EntryWeigher implementations.

Since:

Java 17+

Author:

Kimi Liu

See Also:

• http://code.google.com/p/concurrentlinkedhashmap/

Method Summary

Modifier and Type	Method	Description
static <K, V> EntryWeigher<K,V>	asEntryWeigher(Weigher<? super V> weigher)	A entry weigher backed by the specified weigher.
static Weigher<byte[]>	byteArray()	A weigher where the value is a byte array and its selector is the number of bytes.
static <E> Weigher<? super Collection<E>>	collection()	A weigher where the value is a Collection and its selector is the number of elements.
static <K, V> EntryWeigher<K,V>	entrySingleton()	A weigher where an entry has a selector of 1.
static <E> Weigher<? super Iterable<E>>	iterable()	A weigher where the value is a Iterable and its selector is the number of elements.
static <E> Weigher<? super List<E>>	list()	A weigher where the value is a List and its selector is the number of elements.
static <K, V> Weigher<? super Map<K,V>>	map()	A weigher where the value is a Map and its selector is the number of entries.
static <E> Weigher<? super Set<E>>	set()	A weigher where the value is a Set and its selector is the number of elements.
static <V> Weigher<V>	singleton()	A weigher where a value has a selector of 1.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

asEntryWeigher

public static <K,
V> EntryWeigher<K,V> asEntryWeigher(Weigher<? super V> weigher)

A entry weigher backed by the specified weigher. The selector of the value determines the selector of the entry.

Type Parameters:

K - 键类型

V - 值类型

Parameters:

weigher - the weigher to be "wrapped" in a entry weigher.

Returns:

A entry weigher view of the specified weigher.

entrySingleton

public static <K,
V> EntryWeigher<K,V> entrySingleton()

A weigher where an entry has a selector of 1. A map bounded with this weigher will evict when the number of data-value pairs exceeds the capacity.

Type Parameters:

K - 键类型

V - 值类型

Returns:

A weigher where a value takes one unit of capacity.

singleton

public static <V> Weigher<V> singleton()

A weigher where a value has a selector of 1. A map bounded with this weigher will evict when the number of data-value pairs exceeds the capacity.

Type Parameters:

V - 值类型

Returns:

A weigher where a value takes one unit of capacity.

byteArray

public static Weigher<byte[]> byteArray()

A weigher where the value is a byte array and its selector is the number of bytes. A map bounded with this weigher will evict when the number of bytes exceeds the capacity rather than the number of data-value pairs in the map. This allows for restricting the capacity based on the memory-consumption and is primarily for usage by dedicated caching servers that hold the serialized data.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Returns:

A weigher where each byte takes one unit of capacity.

iterable

public static <E> Weigher<? super Iterable<E>> iterable()

A weigher where the value is a Iterable and its selector is the number of elements. This weigher only should be used when the alternative collection() weigher cannot be, as evaluation takes O(n) time. A map bounded with this weigher will evict when the total number of elements exceeds the capacity rather than the number of data-value pairs in the map.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Type Parameters:

E - 元素类型

Returns:

A weigher where each element takes one unit of capacity.

collection

public static <E> Weigher<? super Collection<E>> collection()

A weigher where the value is a Collection and its selector is the number of elements. A map bounded with this weigher will evict when the total number of elements exceeds the capacity rather than the number of data-value pairs in the map.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Type Parameters:

E - 元素类型

Returns:

A weigher where each element takes one unit of capacity.

list

public static <E> Weigher<? super List<E>> list()

A weigher where the value is a List and its selector is the number of elements. A map bounded with this weigher will evict when the total number of elements exceeds the capacity rather than the number of data-value pairs in the map.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Type Parameters:

E - 元素类型

Returns:

A weigher where each element takes one unit of capacity.

set

public static <E> Weigher<? super Set<E>> set()

A weigher where the value is a Set and its selector is the number of elements. A map bounded with this weigher will evict when the total number of elements exceeds the capacity rather than the number of data-value pairs in the map.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Type Parameters:

E - 元素类型

Returns:

A weigher where each element takes one unit of capacity.

map

public static <K,
V> Weigher<? super Map<K,V>> map()

A weigher where the value is a Map and its selector is the number of entries. A map bounded with this weigher will evict when the total number of entries across all values exceeds the capacity rather than the number of data-value pairs in the map.

A value with a selector of 0 will be rejected by the map. If a value with this selector can occur then the caller should eagerly evaluate the value and treat it as a removal operation. Alternatively, a custom weigher may be specified on the map to assign an empty value a positive selector.

Type Parameters:

K - 键类型

V - 值类型

Returns:

A weigher where each entry takes one unit of capacity.