reactor.cache

Class CacheMono

java.lang.Object

reactor.cache.CacheMono

public class CacheMono
extends Object

Opinionated caching helper that defines how to store and restore a Mono in an arbitrary cache abstraction. A generic writer/reader interface is provided, but cache vendors that have a Map wrapper support can also be directly used.

Example usage:

    LoadingCache graphs = Caffeine.newBuilder()
                                       .maximumSize(10_000)
                                       .expireAfterWrite(5, TimeUnit.MINUTES)
                                       .refreshAfterWrite(1, TimeUnit.MINUTES)
                                       .build(key -> createExpensiveGraph(key));

    keyStream.concatMap(key -> CacheMono.lookup(graphs.asMap(), key)
                                    .onCacheMissResume(repository.findOneById(key))
 

Author:

Oleh Dokuka, Simon Baslé

Constructor Summary

Constructors

Constructor and Description
CacheMono()

Method Summary

Modifier and Type	Method and Description
static <KEY,VALUE> reactor.cache.CacheMono.MonoCacheBuilderCacheMiss<KEY,VALUE>	lookup(reactor.cache.CacheMono.MonoCacheReader<KEY,VALUE> reader, KEY key) Restore a Mono<VALUE> from the MonoCacheReader given a provided key.
static <KEY,VALUE> reactor.cache.CacheMono.MonoCacheBuilderMapMiss<VALUE>	lookup(Map<KEY,? super reactor.core.publisher.Signal<? extends VALUE>> cacheMap, KEY key) Restore a Mono<VALUE> from the cache-map given a provided key.

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheMono

public CacheMono()

Method Detail

lookup

public static <KEY,VALUE> reactor.cache.CacheMono.MonoCacheBuilderMapMiss<VALUE> lookup(Map<KEY,? super reactor.core.publisher.Signal<? extends VALUE>> cacheMap,
                                                                                        KEY key)

Restore a Mono<VALUE> from the cache-map given a provided key. If no value is in the cache, it will be calculated from the original source which is set up in the next step. Note that if the source completes empty, this result will be cached and all subsequent requests with the same key will return Mono.empty(). The behaviour is similar for erroring sources, except cache hits would then return Mono.error(Throwable).

Note that the wrapped Mono is lazy, meaning that subscribing twice in a row to the returned Mono on an empty cache will trigger a cache miss then a cache hit.

Type Parameters:

KEY - Key Type

VALUE - Value Type

Parameters:

cacheMap - Map wrapper of a cache

key - mapped key

Returns:

The next builder step to use to set up the source

lookup

public static <KEY,VALUE> reactor.cache.CacheMono.MonoCacheBuilderCacheMiss<KEY,VALUE> lookup(reactor.cache.CacheMono.MonoCacheReader<KEY,VALUE> reader,
                                                                                              KEY key)

Restore a Mono<VALUE> from the MonoCacheReader given a provided key. If no value is in the cache, it will be calculated from the original source which is set up in the next step. Note that if the source completes empty, this result will be cached and all subsequent requests with the same key will return Mono.empty(). The behaviour is similar for erroring sources, except cache hits would then return Mono.error(Throwable).

Note that the wrapped Mono is lazy, meaning that subscribing twice in a row to the returned Mono on an empty cache will trigger a cache miss then a cache hit.

Type Parameters:

KEY - Key Type

VALUE - Value Type

Parameters:

reader - a MonoCacheReader function that looks up Signal from a cache

key - mapped key

Returns:

The next builder step to use to set up the source