Specification

CaffeineSpec spec = CaffeineSpec.parse(
    "maximumWeight=1000, expireAfterWrite=10m, recordStats");
LoadingCache<Key, Graph> graphs = Caffeine.from(spec)
    .weigher((Key key, Graph graph) -> graph.vertices().size())
    .build(key -> createExpensiveGraph(key));

CaffeineSpec supports parsing a simple configuration format into a Caffeine builder. The string syntax is a series of comma-separated keys or key-value pairs, each corresponding to a builder method. This format does not support configuring builder methods with object parameters, such as removalListener, which must be configured in code.

The format supports the following builder methods. It is illegal to combine maximumSize with maximumWeight or weakValues with softValues.

• initialCapacity=[integer]: sets Caffeine.initialCapacity
• maximumSize=[long]: sets Caffeine.maximumSize
• maximumWeight=[long]: sets Caffeine.maximumWeight
• expireAfterAccess=[duration]: sets Caffeine.expireAfterAccess
• expireAfterWrite=[duration]: sets Caffeine.expireAfterWrite
• refreshAfterWrite=[duration]: sets Caffeine.refreshAfterWrite
• weakKeys: sets Caffeine.weakKeys
• weakValues: sets Caffeine.weakValues
• softValues: sets Caffeine.softValues
• recordStats: sets Caffeine.recordStats

A duration can be represented by an integer followed by one of "d", "h", "m", or "s", representing days, hours, minutes, or seconds respectively. Alternatively, an ISO-8601 format string may be provided and is parsed by Duration.parse. For the purposes of a cache, negative durations are not supported and throws an exception. Some examples of the two formats are below.

Simple	ISO-8601	Description
50s	PT50S	50 seconds
11m	PT11M	11 minutes
6h	PT6H	6 hours
3d	P3D	3 days
	P3DT3H4M	3 days, 3 hours and 4 minutes
	-PT7H3M	-7 hours, -3 minutes (Unsupported)