Package com.fasterxml.jackson.databind.deser

Class DeserializerCache

java.lang.Object

com.fasterxml.jackson.databind.deser.DeserializerCache

All Implemented Interfaces:

Serializable

public final class DeserializerCache
extends Object
implements Serializable

Class that defines caching layer between callers (like ObjectMapper, DeserializationContext) and classes that construct deserializers (DeserializerFactory).

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_MAX_CACHE_SIZE	Default size of the underlying cache to use.

Constructor Summary

Constructors

Constructor	Description
DeserializerCache()
DeserializerCache(int maxSize)
DeserializerCache(LookupCache<JavaType,JsonDeserializer<Object>> cache)

Method Summary

Modifier and Type	Method	Description
int	cachedDeserializersCount()	Method that can be used to determine how many deserializers this provider is caching currently (if it does caching: default implementation does) Exact count depends on what kind of deserializers get cached; default implementation caches only dynamically constructed deserializers, but not eagerly constructed standard deserializers (which is different from how serializer provider works).
DeserializerCache	emptyCopy()
KeyDeserializer	findKeyDeserializer(DeserializationContext ctxt, DeserializerFactory factory, JavaType type)	Method called to get hold of a deserializer to use for deserializing keys for Map.
JsonDeserializer<Object>	findValueDeserializer(DeserializationContext ctxt, DeserializerFactory factory, JavaType propertyType)	Method called to get hold of a deserializer for a value of given type; or if no such deserializer can be found, a default handler (which may do a best-effort generic serialization or just simply throw an exception when invoked).
void	flushCachedDeserializers()	Method that will drop all dynamically constructed deserializers (ones that are counted as result value for cachedDeserializersCount()).
boolean	hasValueDeserializerFor(DeserializationContext ctxt, DeserializerFactory factory, JavaType type)	Method called to find out whether provider would be able to find a deserializer for given type, using a root reference (i.e.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_MAX_CACHE_SIZE

public static final int DEFAULT_MAX_CACHE_SIZE

Default size of the underlying cache to use.

Since:

2.16

See Also:

• Constant Field Values

Constructor Details

DeserializerCache

public DeserializerCache()

DeserializerCache

public DeserializerCache(int maxSize)

DeserializerCache

public DeserializerCache(LookupCache<JavaType,JsonDeserializer<Object>> cache)

Since:

2.16

Method Details

emptyCopy

public DeserializerCache emptyCopy()

Since:

2.16

cachedDeserializersCount

public int cachedDeserializersCount()

Method that can be used to determine how many deserializers this provider is caching currently (if it does caching: default implementation does) Exact count depends on what kind of deserializers get cached; default implementation caches only dynamically constructed deserializers, but not eagerly constructed standard deserializers (which is different from how serializer provider works).

The main use case for this method is to allow conditional flushing of deserializer cache, if certain number of entries is reached.

flushCachedDeserializers

public void flushCachedDeserializers()

Method that will drop all dynamically constructed deserializers (ones that are counted as result value for cachedDeserializersCount()). This can be used to remove memory usage (in case some deserializers are only used once or so), or to force re-construction of deserializers after configuration changes for mapper than owns the provider.

findValueDeserializer

public JsonDeserializer<Object> findValueDeserializer(DeserializationContext ctxt,
 DeserializerFactory factory,
 JavaType propertyType)
                                               throws JsonMappingException

Method called to get hold of a deserializer for a value of given type; or if no such deserializer can be found, a default handler (which may do a best-effort generic serialization or just simply throw an exception when invoked).

Note: this method is only called for value types; not for keys. Key deserializers can be accessed using findKeyDeserializer(com.fasterxml.jackson.databind.DeserializationContext, com.fasterxml.jackson.databind.deser.DeserializerFactory, com.fasterxml.jackson.databind.JavaType).

Note also that deserializer returned is guaranteed to be resolved (if it is of type ResolvableDeserializer), but not contextualized (wrt ContextualDeserializer): caller has to handle latter if necessary.

Parameters:

ctxt - Deserialization context

propertyType - Declared type of the value to deserializer (obtained using 'setter' method signature and/or type annotations

Throws:

JsonMappingException - if there are fatal problems with accessing suitable deserializer; including that of not finding any serializer

findKeyDeserializer

public KeyDeserializer findKeyDeserializer(DeserializationContext ctxt,
 DeserializerFactory factory,
 JavaType type)
                                    throws JsonMappingException

Method called to get hold of a deserializer to use for deserializing keys for Map.

Throws:

JsonMappingException - if there are fatal problems with accessing suitable key deserializer; including that of not finding any serializer

hasValueDeserializerFor

public boolean hasValueDeserializerFor(DeserializationContext ctxt,
 DeserializerFactory factory,
 JavaType type)
                                throws JsonMappingException

Method called to find out whether provider would be able to find a deserializer for given type, using a root reference (i.e. not through fields or membership in an array or collection)

Throws:

JsonMappingException