Package com.fasterxml.jackson.databind.type

Class TypeFactory

java.lang.Object
com.fasterxml.jackson.databind.type.TypeFactory
All Implemented Interfaces:
Serializable
public class TypeFactory extends Object implements Serializable
Class used for creating concrete JavaType instances, given various inputs.

Instances of this class are accessible using ObjectMapper as well as many objects it constructs (like DeserializationConfig and SerializationConfig)), but usually those objects also expose convenience methods (constructType). So, you can do for example: 

   JavaType stringType = mapper.constructType(String.class);
However, more advanced methods are only exposed by factory so that you may need to use: 
   JavaType stringCollection = mapper.getTypeFactory().constructCollectionType(List.class, String.class);

Note on optimizations: generic type parameters are resolved for all types, with following exceptions:

  • For optimization purposes, type resolution is skipped for following commonly seen types that do have type parameters, but ones that are rarely needed:
    • Enum: Self-referential type reference is simply dropped and Class is exposed as a simple, non-parameterized SimpleType
    • Comparable: Type parameter is simply dropped and and interface is exposed as a simple, non-parameterized SimpleType
    • Up until Jackson 2.13, Class type parameter was dropped; resolution was added back in Jackson 2.14.
  • For Collection subtypes, resolved type is ALWAYS the parameter for {link java.util.Collection} and not that of actually resolved subtype. This is usually (but not always) same parameter.
  • For Map subtypes, resolved type is ALWAYS the parameter for {link java.util.Map} and not that of actually resolved subtype. These are usually (but not always) same parameters.
See Also:

  • Field Details

    • DEFAULT_MAX_CACHE_SIZE

      public static final int DEFAULT_MAX_CACHE_SIZE
      Default size used to construct _typeCache. Used to be passed inline.
      Since:
      2.16
      See Also:

  • Method Details

    • withModifier

      public TypeFactory withModifier(TypeModifier mod)
      "Mutant factory" method which will construct a new instance with specified TypeModifier added as the first modifier to call (in case there are multiple registered).

    • withClassLoader

      public TypeFactory withClassLoader(ClassLoader classLoader)
      "Mutant factory" method which will construct a new instance with specified ClassLoader to use by findClass(java.lang.String).

    • withCache

      @Deprecated public TypeFactory withCache(LRUMap<Object,JavaType> cache)
      Deprecated.
      Since 2.12
      Mutant factory method that will construct new TypeFactory with identical settings except for different cache; most likely one with bigger maximum size.
      Since:
      2.8

    • withCache

      public TypeFactory withCache(LookupCache<Object,JavaType> cache)
      Mutant factory method that will construct new TypeFactory with identical settings except for different cache.
      Since:
      2.12

    • defaultInstance

      public static TypeFactory defaultInstance()
      Method used to access the globally shared instance, which has no custom configuration. Used by ObjectMapper to get the default factory when constructed.

    • clearCache

      public void clearCache()
      Method that will clear up any cached type definitions that may be cached by this TypeFactory instance. This method should not be commonly used, that is, only use it if you know there is a problem with retention of type definitions; the most likely (and currently only known) problem is retention of Class instances via JavaType reference.
      Since:
      2.4.1

    • getClassLoader

      public ClassLoader getClassLoader()

    • unknownType

      public static JavaType unknownType()
      Method for constructing a marker type that indicates missing generic type information, which is handled same as simple type for java.lang.Object.

    • rawClass

      public static Class<?> rawClass(Type t)
      Static helper method that can be called to figure out type-erased call for given JDK type. It can be called statically since type resolution process can never change actual type-erased class; thereby static default instance is used for determination.

    • findClass

      public Class<?> findClass(String className) throws ClassNotFoundException
      Low-level lookup method moved from ClassUtil, to allow for overriding of lookup functionality in environments like OSGi.
      Throws:
      ClassNotFoundException
      Since:
      2.6

    • constructSpecializedType

      public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass) throws IllegalArgumentException
      Factory method for creating a subtype of given base type, as defined by specified subclass; but retaining generic type information if any. Can be used, for example, to get equivalent of "HashMap<String,Integer>" from "Map<String,Integer>" by giving HashMap.class as subclass. Short-cut for: 
       constructSpecializedType(baseType, subclass, class);
      that is, will use "strict" compatibility checking, usually used for deserialization purposes (but often not for serialization).
      Throws:
      IllegalArgumentException

    • constructSpecializedType

      public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass, boolean relaxedCompatibilityCheck) throws IllegalArgumentException
      Factory method for creating a subtype of given base type, as defined by specified subclass; but retaining generic type information if any. Can be used, for example, to get equivalent of "HashMap<String,Integer>" from "Map<String,Integer>" by giving HashMap.class as subclass.
      Parameters:
      baseType - Declared base type with resolved type parameters
      subclass - Runtime subtype to use for resolving
      relaxedCompatibilityCheck - Whether checking for type-assignment compatibility should be "relaxed" (true) or "strict" (false): typically serialization uses relaxed, deserialization strict checking.
      Returns:
      Resolved sub-type
      Throws:
      IllegalArgumentException
      Since:
      2.11

    • constructGeneralizedType

      public JavaType constructGeneralizedType(JavaType baseType, Class<?> superClass)
      Method similar to constructSpecializedType(com.fasterxml.jackson.databind.JavaType, java.lang.Class<?>), but that creates a less-specific type of given type. Usually this is as simple as simply finding super-type with type erasure of superClass, but there may be need for some additional work-arounds.
      Parameters:
      superClass -
      Since:
      2.7

    • constructFromCanonical

      public JavaType constructFromCanonical(String canonical) throws IllegalArgumentException
      Factory method for constructing a JavaType out of its canonical representation (see ResolvedType.toCanonical()).
      Parameters:
      canonical - Canonical string representation of a type
      Throws:
      IllegalArgumentException - If canonical representation is malformed, or class that type represents (including its generic parameters) is not found

    • findTypeParameters

      public JavaType[] findTypeParameters(JavaType type, Class<?> expType)
      Method that is to figure out actual type parameters that given class binds to generic types defined by given (generic) interface or class. This could mean, for example, trying to figure out key and value types for Map implementations.
      Parameters:
      type - Sub-type (leaf type) that implements expType

    • findFirstTypeParameter

      public JavaType findFirstTypeParameter(JavaType type, Class<?> expType)
      Specialized alternative to findTypeParameters(com.fasterxml.jackson.databind.JavaType, java.lang.Class<?>)
      Since:
      2.16 (backported from Jackson 3.0)

    • findTypeParameters

      @Deprecated public JavaType[] findTypeParameters(Class<?> clz, Class<?> expType, TypeBindings bindings)
      Deprecated.
      Since 2.7 resolve raw type first, then find type parameters

    • findTypeParameters

      @Deprecated public JavaType[] findTypeParameters(Class<?> clz, Class<?> expType)
      Deprecated.
      Since 2.7 resolve raw type first, then find type parameters

    • moreSpecificType

      public JavaType moreSpecificType(JavaType type1, JavaType type2)
      Method that can be called to figure out more specific of two types (if they are related; that is, one implements or extends the other); or if not related, return the primary type.
      Parameters:
      type1 - Primary type to consider
      type2 - Secondary type to consider
      Since:
      2.2

    • constructType

      public JavaType constructType(Type type)

    • constructType

      public JavaType constructType(TypeReference<?> typeRef)

    • resolveMemberType

      public JavaType resolveMemberType(Type type, TypeBindings contextBindings)
      Method to call when resolving types of Members like Fields, Methods and Constructor parameters and there is a TypeBindings (that describes binding of type parameters within context) to pass. This is typically used only by code in databind itself.
      Parameters:
      type - Type of a Member to resolve
      contextBindings - Type bindings from the context, often class in which member declared but may be subtype of that type (to bind actual bound type parametrers). Not used if type is of type Class<?>.
      Returns:
      Fully resolve type
      Since:
      2.12 as replacement for deprecated constructType(Type, TypeBindings)

    • constructType

      @Deprecated public JavaType constructType(Type type, TypeBindings bindings)
      Deprecated.
      Since 2.12
      Method that you very likely should NOT be using -- you need to know a lot about internal details of TypeBindings and even then it will probably not do what you want. Usually you would instead want to call one of constructXxxType() methods (where Xxx would be "Array", "Collection[Like]", "Map[Like]" or "Parametric").

    • constructType

      @Deprecated public JavaType constructType(Type type, Class<?> contextClass)
      Deprecated.
      Since 2.7 (accidentally removed in 2.7.0; added back in 2.7.1)

    • constructType

      @Deprecated public JavaType constructType(Type type, JavaType contextType)
      Deprecated.
      Since 2.7 (accidentally removed in 2.7.0; added back in 2.7.1)

    • constructArrayType

      public ArrayType constructArrayType(Class<?> elementType)
      Method for constructing an ArrayType.

      NOTE: type modifiers are NOT called on array type itself; but are called for element type (and other contained types)

    • constructArrayType

      public ArrayType constructArrayType(JavaType elementType)
      Method for constructing an ArrayType.

      NOTE: type modifiers are NOT called on array type itself; but are called for contained types.

    • constructCollectionType

      public CollectionType constructCollectionType(Class<? extends Collection> collectionClass, Class<?> elementClass)
      Method for constructing a CollectionType.

      NOTE: type modifiers are NOT called on Collection type itself; but are called for contained types.

    • constructCollectionType

      public CollectionType constructCollectionType(Class<? extends Collection> collectionClass, JavaType elementType)
      Method for constructing a CollectionType.

      NOTE: type modifiers are NOT called on Collection type itself; but are called for contained types.

    • constructCollectionLikeType

      public CollectionLikeType constructCollectionLikeType(Class<?> collectionClass, Class<?> elementClass)
      Method for constructing a CollectionLikeType.

      NOTE: type modifiers are NOT called on constructed type itself; but are called for contained types.

    • constructCollectionLikeType

      public CollectionLikeType constructCollectionLikeType(Class<?> collectionClass, JavaType elementType)
      Method for constructing a CollectionLikeType.

      NOTE: type modifiers are NOT called on constructed type itself; but are called for contained types.

    • constructMapType

      public MapType constructMapType(Class<? extends Map> mapClass, Class<?> keyClass, Class<?> valueClass)
      Method for constructing a MapType instance

      NOTE: type modifiers are NOT called on constructed type itself; but are called for contained types.

    • constructMapType

      public MapType constructMapType(Class<? extends Map> mapClass, JavaType keyType, JavaType valueType)
      Method for constructing a MapType instance

      NOTE: type modifiers are NOT called on constructed type itself.

    • constructMapLikeType

      public MapLikeType constructMapLikeType(Class<?> mapClass, Class<?> keyClass, Class<?> valueClass)
      Method for constructing a MapLikeType instance.

      Do not use this method to create a true Map type -- use constructMapType(java.lang.Class<? extends java.util.Map>, java.lang.Class<?>, java.lang.Class<?>) instead. Map-like types are only meant for supporting things that do not implement Map interface and as such cannot use standard Map handlers.

      NOTE: type modifiers are NOT called on constructed type itself; but are called for contained types.

    • constructMapLikeType

      public MapLikeType constructMapLikeType(Class<?> mapClass, JavaType keyType, JavaType valueType)
      Method for constructing a MapLikeType instance

      Do not use this method to create a true Map type -- use constructMapType(java.lang.Class<? extends java.util.Map>, java.lang.Class<?>, java.lang.Class<?>) instead. Map-like types are only meant for supporting things that do not implement Map interface and as such cannot use standard Map handlers.

      NOTE: type modifiers are NOT called on constructed type itself.

    • constructSimpleType

      public JavaType constructSimpleType(Class<?> rawType, JavaType[] parameterTypes)
      Method for constructing a type instance with specified parameterization.

      NOTE: type modifiers are NOT called on constructed type itself.

    • constructSimpleType

      @Deprecated public JavaType constructSimpleType(Class<?> rawType, Class<?> parameterTarget, JavaType[] parameterTypes)
      Deprecated.
      Since 2.7
      Method for constructing a type instance with specified parameterization.
      Since:
      2.6

    • constructReferenceType

      public JavaType constructReferenceType(Class<?> rawType, JavaType referredType)
      Method for constructing a ReferenceType instance with given type parameter (type MUST take one and only one type parameter)

      NOTE: type modifiers are NOT called on constructed type itself.

      Since:
      2.6

    • uncheckedSimpleType

      @Deprecated public JavaType uncheckedSimpleType(Class<?> cls)
      Deprecated.
      Since 2.8, to indicate users should never call this method.
      Method that use by core Databind functionality, and that should NOT be called by application code outside databind package.

      Unchecked here not only means that no checks are made as to whether given class might be non-simple type (like CollectionType) but also that most of supertype information is not gathered. This means that unless called on primitive types or String, results are probably not what you want to use.

    • constructParametricType

      public JavaType constructParametricType(Class<?> parametrized, Class<?>... parameterClasses)
      Factory method for constructing JavaType that represents a parameterized type. For example, to represent type List<Set<Integer>>, you could call 
        JavaType inner = TypeFactory.constructParametricType(Set.class, Integer.class);
  return TypeFactory.constructParametricType(List.class, inner);

      NOTE: since 2.11.2 TypeModifiers ARE called on result (fix for [databind#2796])

      Parameters:
      parametrized - Type-erased type to parameterize
      parameterClasses - Type parameters to apply
      Since:
      2.5 NOTE: was briefly deprecated for 2.6

    • constructParametricType

      public JavaType constructParametricType(Class<?> rawType, JavaType... parameterTypes)
      Factory method for constructing JavaType that represents a parameterized type. For example, to represent type List<Set<Integer>>, you could 
        JavaType inner = TypeFactory.constructParametricType(Set.class, Integer.class);
  return TypeFactory.constructParametricType(List.class, inner);

      NOTE: since 2.11.2 TypeModifiers ARE called on result (fix for [databind#2796])

      Parameters:
      rawType - Actual type-erased type
      parameterTypes - Type parameters to apply
      Returns:
      Fully resolved type for given base type and type parameters

    • constructParametricType

      public JavaType constructParametricType(Class<?> rawType, TypeBindings parameterTypes)
      Factory method for constructing JavaType that represents a parameterized type. The type's parameters are specified as an instance of TypeBindings. This is useful if you already have the type's parameters such as those found on JavaType. For example, you could call 
         return TypeFactory.constructParametricType(ArrayList.class, javaType.getBindings());
      This effectively applies the parameterized types from one JavaType to another class.
      Parameters:
      rawType - Actual type-erased type
      parameterTypes - Type bindings for the raw type
      Since:
      2.12

    • constructParametrizedType

      @Deprecated public JavaType constructParametrizedType(Class<?> parametrized, Class<?> parametersFor, JavaType... parameterTypes)
      Deprecated.
      since 2.9 Use constructParametricType(Class,JavaType...) instead
      Since:
      2.5

    • constructParametrizedType

      @Deprecated public JavaType constructParametrizedType(Class<?> parametrized, Class<?> parametersFor, Class<?>... parameterClasses)
      Deprecated.
      since 2.9 Use constructParametricType(Class,Class...) instead
      Since:
      2.5

    • constructRawCollectionType

      public CollectionType constructRawCollectionType(Class<? extends Collection> collectionClass)
      Method that can be used to construct "raw" Collection type; meaning that its parameterization is unknown. This is similar to using Object.class parameterization, and is equivalent to calling: 
        typeFactory.constructCollectionType(collectionClass, typeFactory.unknownType());

      This method should only be used if parameterization is completely unavailable.

    • constructRawCollectionLikeType

      public CollectionLikeType constructRawCollectionLikeType(Class<?> collectionClass)
      Method that can be used to construct "raw" Collection-like type; meaning that its parameterization is unknown. This is similar to using Object.class parameterization, and is equivalent to calling: 
        typeFactory.constructCollectionLikeType(collectionClass, typeFactory.unknownType());

      This method should only be used if parameterization is completely unavailable.

    • constructRawMapType

      public MapType constructRawMapType(Class<? extends Map> mapClass)
      Method that can be used to construct "raw" Map type; meaning that its parameterization is unknown. This is similar to using Object.class parameterization, and is equivalent to calling: 
        typeFactory.constructMapType(collectionClass, typeFactory.unknownType(), typeFactory.unknownType());

      This method should only be used if parameterization is completely unavailable.

    • constructRawMapLikeType

      public MapLikeType constructRawMapLikeType(Class<?> mapClass)
      Method that can be used to construct "raw" Map-like type; meaning that its parameterization is unknown. This is similar to using Object.class parameterization, and is equivalent to calling: 
        typeFactory.constructMapLikeType(collectionClass, typeFactory.unknownType(), typeFactory.unknownType());

      This method should only be used if parameterization is completely unavailable.