Package org.ametys.core.util

Class CachedValue<T>

java.lang.Object

org.ametys.core.util.CachedValue<T>

Type Parameters:

T - The type of the cached value

public class CachedValue<T>
extends Object

A cached value. It can be constructed with withInitial(java.util.function.Supplier<T>) with a Supplier to pass in order to compute the value to cache on the first call of get().
It can also be constructed with withExpiryDuration(java.util.function.Supplier<T>, java.time.Duration) with the Supplier and an expiry Duration to automatically force the reload of the value.
The supplier is ensured to be called once (until uncache() is called, or after the expiry duration has elapsed since the last computing), even with multiple callers at the same time.
The returned value by the supplier must not be null

Field Summary

Fields

Modifier and Type	Field	Description
private static Object	__ALL_CACHES_ONLY_KEY
private LoadingCache<Object,T>	_loadingCache

Constructor Summary

Constructors

Constructor	Description
CachedValue(Supplier<T> supplier, Duration expiryDuration, Ticker ticker)

Method Summary

Modifier and Type	Method	Description
(package private) CacheBuilder<Object,Object>	_cacheBuilder(Duration expiryDuration, Ticker ticker)
private static <T> CacheLoader<Object,T>	_cacheLoader(Supplier<T> supplier)
T	get()	Returns the value.
void	uncache()	Uncache the value.
static <T> CachedValue<T>	withExpiryDuration(Supplier<T> supplier, Duration expiryDuration)	Creates a cached value.
static <T> CachedValue<T>	withInitial(Supplier<T> supplier)	Creates a cached value.

Methods inherited from class java.lang.Object

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

Field Detail

__ALL_CACHES_ONLY_KEY

private static final Object __ALL_CACHES_ONLY_KEY

_loadingCache

private LoadingCache<Object,T> _loadingCache

Constructor Detail

CachedValue

CachedValue(Supplier<T> supplier,
            Duration expiryDuration,
            Ticker ticker)

Method Detail

withInitial

public static <T> CachedValue<T> withInitial(Supplier<T> supplier)

Creates a cached value. The value will be computed by invoking the given supplier when the get() method will be called the first time.

Type Parameters:

T - The type of the cached value

Parameters:

supplier - The supplier which will be invoked only once in order to compute the value to cache. The value must not be null

Returns:

The CachedValue

withExpiryDuration

public static <T> CachedValue<T> withExpiryDuration(Supplier<T> supplier,
                                                    Duration expiryDuration)

Creates a cached value. The value will be computed by invoking the given supplier when the get() method will be called the very first time, and every first time after the given Duration is expired.

Type Parameters:

T - The type of the cached value

Parameters:

supplier - The supplier which will be invoked only once in order to compute the value to cache. The value must not be null

expiryDuration - The expiry duration

Returns:

The CachedValue

_cacheBuilder

CacheBuilder<Object,Object> _cacheBuilder(Duration expiryDuration,
                                                Ticker ticker)

_cacheLoader

private static <T> CacheLoader<Object,T> _cacheLoader(Supplier<T> supplier)

get

public T get()

Returns the value. If it is the first time it is called, then it is computed by invoking the supplier function. Otherwise, the cached value is returned.

Returns:

the value

uncache

public void uncache()

Uncache the value. Mostly to force to re-compute the value.