sirius.kernel.cache

Class CacheManager

java.lang.Object

sirius.kernel.cache.CacheManager

public class CacheManager
extends Object

Provides access to all managed caches

Is responsible for creating new caches using createCache(String). Also, this class keeps track of all known caches.

Additionally instances of InlineCache can be created, which can be used to compute a single value, which is then cached for a given amount of time.

Field Summary

Fields

Modifier and Type	Field and Description
protected static Log	LOG Logged used by the caching system

Method Summary

Modifier and Type	Method and Description
static <K,V> Cache<K,V>	createCache(String name) Creates a cached with the given name.
static <K,V> Cache<K,V>	createCache(String name, ValueComputer<K,V> valueComputer, ValueVerifier<V> verifier) Creates a cache with the given name.
static <E> InlineCache<E>	createInlineCache(Duration ttl, Supplier<E> computer) Creates a new InlineCache with the given TTL and computer.
static <E> InlineCache<E>	createTenSecondsInlineCache(Supplier<E> computer) Boilerplate method for createInlineCache(Duration, Supplier) which keeps the computed value for up to 10 seconds.
static List<sirius.kernel.cache.ManagedCache<?,?>>	getCaches() Returns a list of all known caches

Methods inherited from class java.lang.Object

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

Field Detail

LOG

protected static final Log LOG

Logged used by the caching system

Method Detail

getCaches

public static List<sirius.kernel.cache.ManagedCache<?,?>> getCaches()

Returns a list of all known caches

Returns:

a list of all caches created so far

createCache

public static <K,V> Cache<K,V> createCache(String name,
                                           ValueComputer<K,V> valueComputer,
                                           ValueVerifier<V> verifier)

Creates a cache with the given name.

The name is used to load the settings from the system configuration, using the extension cache.[name]. If a value is absent in the cache, the given valueComputer is used to generate the requested value. If a value is fetched from the cache, it is verified by the given verifier in certain intervals before it is returned to the user.

The system config can provide the following values:

• maxSize: max number of entries in the cache
• ttl: a duration specifying the max lifetime of a cached entry.
• verification: a duration specifying in which interval a verification of a value will take place (if possible)

Type Parameters:

K - the key field used to identify cache entries

V - the value type used by the cache

Parameters:

name - the name of the cache, used to load the appropriate extension from the config

valueComputer - used to compute a value, if no valid value was found in the cache for the given key. Can be null if there is no appropriate way to compute such a value. In this case, the cache will simply return null.

verifier - used to verify a value before it is returned to the user. Note that the value is not verified each time, but in given intervals. If the verifier is null, no verification will take place.

Returns:

a newly created cache according to the given parameters and the settings in the system config

createCache

public static <K,V> Cache<K,V> createCache(String name)

Creates a cached with the given name.

This is just a shortcut for createCache(String, ValueComputer, ValueVerifier) with neither a ValueComputer nor a ValueVerifier supplied.

Type Parameters:

K - the key field used to identify cache entries

V - the value type used by the cache

Parameters:

name - the name of the cache (used to fetch settings from the system config

Returns:

the newly created cache

See Also:

createCache(String, ValueComputer, ValueVerifier)

createInlineCache

public static <E> InlineCache<E> createInlineCache(Duration ttl,
                                                   Supplier<E> computer)

Creates a new InlineCache with the given TTL and computer.

An inline cache can be used to compute a single value, which is then cached for a certain amount of time.

Type Parameters:

E - the type of values being cached

Parameters:

ttl - specifies the duration which the computed value will be cached

computer - the provider which is used to re-compute the value once it expired

Returns:

an inline cache which keeps a computed value for the given amount of time and then uses the provided computer to re-compute the value

createTenSecondsInlineCache

public static <E> InlineCache<E> createTenSecondsInlineCache(Supplier<E> computer)

Boilerplate method for createInlineCache(Duration, Supplier) which keeps the computed value for up to 10 seconds.

Type Parameters:

E - the type of values being cached

Parameters:

computer - the provider which is used to re-compute the value once it expired

Returns:

an inline cache which keeps a computed value for ten seconds and then uses the provided computer to re-compute the value