org.omnifaces.component.output.cache.concurrentlinkedhashmap
Class Weighers

java.lang.Object
  org.omnifaces.component.output.cache.concurrentlinkedhashmap.Weighers

public final class Weighers
extends java.lang.Object

A common set of Weigher and EntryWeigher implementations.

Author:

[email protected] (Ben Manes)

See Also:

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

Method Summary

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 weight is the number of bytes.
static <E> Weigher<? super java.util.Collection<E>>	collection() A weigher where the value is a Collection and its weight is the number of elements.
static <K,V> EntryWeigher<K,V>	entrySingleton() A weigher where an entry has a weight of 1.
static <E> Weigher<? super java.lang.Iterable<E>>	iterable() A weigher where the value is a Iterable and its weight is the number of elements.
static <E> Weigher<? super java.util.List<E>>	list() A weigher where the value is a List and its weight is the number of elements.
static <A,B> Weigher<? super java.util.Map<A,B>>	map() A weigher where the value is a Map and its weight is the number of entries.
static <E> Weigher<? super java.util.Set<E>>	set() A weigher where the value is a Set and its weight is the number of elements.
static <V> Weigher<V>	singleton() A weigher where a value has a weight of 1.

Methods inherited from class java.lang.Object

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

Method Detail

asEntryWeigher

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

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

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 weight of 1. A map bounded with this weigher will evict when the number of key-value pairs exceeds the capacity.

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 weight of 1. A map bounded with this weigher will evict when the number of key-value pairs exceeds the capacity.

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 weight 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 key-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 weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each byte takes one unit of capacity.

iterable

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

A weigher where the value is a Iterable and its weight 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 key-value pairs in the map.

A value with a weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each element takes one unit of capacity.

collection

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

A weigher where the value is a Collection and its weight 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 key-value pairs in the map.

A value with a weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each element takes one unit of capacity.

list

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

A weigher where the value is a List and its weight 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 key-value pairs in the map.

A value with a weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each element takes one unit of capacity.

set

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

A weigher where the value is a Set and its weight 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 key-value pairs in the map.

A value with a weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each element takes one unit of capacity.

map

public static <A,B> Weigher<? super java.util.Map<A,B>> map()

A weigher where the value is a Map and its weight 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 key-value pairs in the map.

A value with a weight of 0 will be rejected by the map. If a value with this weight 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 weight.

Returns:

A weigher where each entry takes one unit of capacity.