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jackson-caffeine-cache

A Caffeine based type cache for Jackson. This is built with Caffeine 2.9 in order to support Java 8. If you are using Java 11 or above, it is recommended that you have your build pick up the latest Cafferine 3.x jar. It is expected that this will work ok with jackson-caffeine-cache.

The built-in type cache (LRUMap) in Jackson has synchronization that might cause performance issues if you have a lot of types in the cache (see issue). In older versions of Jackson, LRUMap emptied the cache when it filled up. The Caffeine cache will remove the oldest entries (as does LRUMap since the Jackson 2.14.0 release).

To use an LRUMap with larger max size:

    LRUMap<Object, JavaType> cache = new LRUMap(4, 1000);
    TypeFactory tf = TypeFactory.defaultInstance().withCache(cache);
    ObjectMapper mapper = new ObjectMapper();
    mapper.setTypeFactory(tf);
    //or ObjectMapper mapper = JsonMapper.builder().typeFactory(tf).build();

To use this Caffeine based cache:

    CaffeineLookupCache<Object, JavaType> cache = new CaffeineLookupCache(1000);
    TypeFactory tf = TypeFactory.defaultInstance().withCache(cache);
    ObjectMapper mapper = new ObjectMapper();
    mapper.setTypeFactory(tf);
    //or ObjectMapper mapper = JsonMapper.builder().typeFactory(tf).build();
    

Jackson 2.11

jackson-caffeine-cache 1.0.1 is the right version to use with Jackson 2.11.

Jackson 2.12 and above

jackson-caffeine-cache 1.1.0 was refactored to take advantage of a change in Jackson 2.12.0. LRUMap now implements a LookupCache interface. This makes it easier to create custom cache implementations.

CaffeineLookupCache will still work with TypeFactory, as above. Some Jackson APIs still require an LRUMap. If you want to use a Caffeine-based cache instead of a LRUMap, there is a new CaffeineLRUMap.

Jackson-Module-Scala

After the v2.12.2 release, it is possible to replace the default LRUMap descriptorCache.

    import com.fasterxml.jackson.databind.type.ClassKey
    import com.fasterxml.jackson.module.scala.introspect._
    
    val cache = new CaffeineLookupCache[ClassKey, BeanDescriptor](1000)
    ScalaAnnotationIntrospector.setDescriptorCache(cache)
    //after v2.13.1 is released, the method is deprecated and replaced by 
    ScalaAnnotationIntrospectorModule.setDescriptorCache(cache)