com.fasterxml.jackson.databind

Class JavaType

java.lang.Object

com.fasterxml.jackson.core.type.ResolvedType

com.fasterxml.jackson.databind.JavaType

All Implemented Interfaces:

Serializable, Type

Direct Known Subclasses:

TypeBase

public abstract class JavaType
extends ResolvedType
implements Serializable, Type

Base class for type token classes used both to contain information and as keys for deserializers.

Instances can (only) be constructed by com.fasterxml.jackson.databind.TypeFactory.

Since 2.2 this implements Type to allow it to be pushed through interfaces that only expose that type.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	_asStatic Whether entities defined with this type should be handled using static typing (as opposed to dynamic runtime type) or not.
protected Class<?>	_class This is the nominal type-erased Class that would be close to the type represented (but not exactly type, due to type erasure: type instance may have more information on this).
protected int	_hash
protected Object	_typeHandler Optional handler that can be attached to indicate how to handle additional type metadata associated with this type.
protected Object	_valueHandler Optional handler (codec) that can be attached to indicate what to use for handling (serializing, deserializing) values of this specific type.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JavaType(Class<?> raw, int additionalHash, Object valueHandler, Object typeHandler, boolean asStatic)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	_assertSubclass(Class<?> subclass, Class<?> superClass)
protected abstract JavaType	_narrow(Class<?> subclass)
protected JavaType	_widen(Class<?> superclass) Default implementation is just to call _narrow(java.lang.Class<?>), since underlying type construction is usually identical
JavaType	containedType(int index)
int	containedTypeCount()
String	containedTypeName(int index)
abstract boolean	equals(Object o)
JavaType	forcedNarrowBy(Class<?> subclass) More efficient version of narrowBy(java.lang.Class<?>), called by internal framework in cases where compatibility checks are to be skipped.
JavaType	getContentType()
String	getErasedSignature() Method for accessing signature without generic type information, in form compatible with all versions of JVM, and specifically used for type descriptions when generating byte code.
abstract StringBuilder	getErasedSignature(StringBuilder sb) Method for accessing signature without generic type information, in form compatible with all versions of JVM, and specifically used for type descriptions when generating byte code.
String	getGenericSignature() Method for accessing signature that contains generic type information, in form compatible with JVM 1.5 as per JLS.
abstract StringBuilder	getGenericSignature(StringBuilder sb)
JavaType	getKeyType()
Class<?>	getRawClass()
<T> T	getTypeHandler() Method for accessing type handler associated with this type, if any
<T> T	getValueHandler() Method for accessing value handler associated with this type, if any
boolean	hasGenericTypes()
int	hashCode()
boolean	hasRawClass(Class<?> clz) Method that can be used to check whether this type has specified Class as its type erasure.
boolean	isAbstract()
boolean	isArrayType()
boolean	isCollectionLikeType()
boolean	isConcrete() Convenience method for checking whether underlying Java type is a concrete class or not: abstract classes and interfaces are not.
abstract boolean	isContainerType()
boolean	isEnumType()
boolean	isFinal()
boolean	isInterface()
boolean	isMapLikeType()
boolean	isPrimitive()
boolean	isThrowable()
JavaType	narrowBy(Class<?> subclass) Method that can be called to do a "narrowing" conversions; that is, to return a type with a raw class that is assignable to the raw class of this type.
abstract JavaType	narrowContentsBy(Class<?> contentClass)
abstract String	toString()
boolean	useStaticType() Accessor for checking whether handlers for dealing with values of this type should use static typing (as opposed to dynamic typing).
JavaType	widenBy(Class<?> superclass) Method that can be called to do a "widening" conversions; that is, to return a type with a raw class that could be assigned from this type.
abstract JavaType	widenContentsBy(Class<?> contentClass)
abstract JavaType	withContentTypeHandler(Object h) "Copy method" that will construct a new instance that is identical to this instance, except that its content type will have specified type handler assigned.
abstract JavaType	withContentValueHandler(Object h) "Copy method" that will construct a new instance that is identical to this instance, except that it will have specified content value handler assigned.
abstract JavaType	withStaticTyping() Method that can be called to get a type instance that indicates that values of the type should be handled using "static typing" for purposes of serialization (as opposed to "dynamic" aka runtime typing): meaning that no runtime information is needed for determining serializers to use.
abstract JavaType	withTypeHandler(Object h) "Copy method" that will construct a new instance that is identical to this instance, except that it will have specified type handler assigned.
abstract JavaType	withValueHandler(Object h) "Copy method" that will construct a new instance that is identical to this instance, except that it will have specified value handler assigned.

Methods inherited from class com.fasterxml.jackson.core.type.ResolvedType

toCanonical

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

_class

protected final Class<?> _class

This is the nominal type-erased Class that would be close to the type represented (but not exactly type, due to type erasure: type instance may have more information on this). May be an interface or abstract class, so instantiation may not be possible.

_hash

protected final int _hash

_valueHandler

protected final Object _valueHandler

Optional handler (codec) that can be attached to indicate what to use for handling (serializing, deserializing) values of this specific type.

Note: untyped (i.e. caller has to cast) because it is used for different kinds of handlers, with unrelated types.

_typeHandler

protected final Object _typeHandler

Optional handler that can be attached to indicate how to handle additional type metadata associated with this type.

Note: untyped (i.e. caller has to cast) because it is used for different kinds of handlers, with unrelated types.

_asStatic

protected final boolean _asStatic

Whether entities defined with this type should be handled using static typing (as opposed to dynamic runtime type) or not.

Since:

2.2

Constructor Detail

JavaType

protected JavaType(Class<?> raw,
        int additionalHash,
        Object valueHandler,
        Object typeHandler,
        boolean asStatic)

Parameters:

raw - "Raw" (type-erased) class for this type

additionalHash - Additional hash code to use, in addition to hash code of the class name

Method Detail

withTypeHandler

public abstract JavaType withTypeHandler(Object h)

"Copy method" that will construct a new instance that is identical to this instance, except that it will have specified type handler assigned.

Returns:

Newly created type instance

withContentTypeHandler

public abstract JavaType withContentTypeHandler(Object h)

"Copy method" that will construct a new instance that is identical to this instance, except that its content type will have specified type handler assigned.

Returns:

Newly created type instance

withValueHandler

public abstract JavaType withValueHandler(Object h)

"Copy method" that will construct a new instance that is identical to this instance, except that it will have specified value handler assigned.

Returns:

Newly created type instance

withContentValueHandler

public abstract JavaType withContentValueHandler(Object h)

"Copy method" that will construct a new instance that is identical to this instance, except that it will have specified content value handler assigned.

Returns:

Newly created type instance

withStaticTyping

public abstract JavaType withStaticTyping()

Method that can be called to get a type instance that indicates that values of the type should be handled using "static typing" for purposes of serialization (as opposed to "dynamic" aka runtime typing): meaning that no runtime information is needed for determining serializers to use. The main use case is to allow forcing of specific root value serialization type, and specifically in resolving serializers for contained types (element types for arrays, Collections and Maps).

Since:

2.2

narrowBy

public JavaType narrowBy(Class<?> subclass)

Method that can be called to do a "narrowing" conversions; that is, to return a type with a raw class that is assignable to the raw class of this type. If this is not possible, an IllegalArgumentException is thrown. If class is same as the current raw class, instance itself is returned.

forcedNarrowBy

public JavaType forcedNarrowBy(Class<?> subclass)

More efficient version of narrowBy(java.lang.Class<?>), called by internal framework in cases where compatibility checks are to be skipped.

widenBy

public JavaType widenBy(Class<?> superclass)

Method that can be called to do a "widening" conversions; that is, to return a type with a raw class that could be assigned from this type. If such conversion is not possible, an IllegalArgumentException is thrown. If class is same as the current raw class, instance itself is returned.

_narrow

protected abstract JavaType _narrow(Class<?> subclass)

_widen

protected JavaType _widen(Class<?> superclass)

Default implementation is just to call _narrow(java.lang.Class<?>), since underlying type construction is usually identical

narrowContentsBy

public abstract JavaType narrowContentsBy(Class<?> contentClass)

widenContentsBy

public abstract JavaType widenContentsBy(Class<?> contentClass)

getRawClass

public final Class<?> getRawClass()

Specified by:

getRawClass in class ResolvedType

hasRawClass

public final boolean hasRawClass(Class<?> clz)

Method that can be used to check whether this type has specified Class as its type erasure. Put another way, returns true if instantiation of this Type is given (type-erased) Class.

Specified by:

hasRawClass in class ResolvedType

isAbstract

public boolean isAbstract()

Specified by:

isAbstract in class ResolvedType

isConcrete

public boolean isConcrete()

Convenience method for checking whether underlying Java type is a concrete class or not: abstract classes and interfaces are not.

Specified by:

isConcrete in class ResolvedType

isThrowable

public boolean isThrowable()

Specified by:

isThrowable in class ResolvedType

isArrayType

public boolean isArrayType()

Specified by:

isArrayType in class ResolvedType

isEnumType

public final boolean isEnumType()

Specified by:

isEnumType in class ResolvedType

isInterface

public final boolean isInterface()

Specified by:

isInterface in class ResolvedType

isPrimitive

public final boolean isPrimitive()

Specified by:

isPrimitive in class ResolvedType

isFinal

public final boolean isFinal()

Specified by:

isFinal in class ResolvedType

isContainerType

public abstract boolean isContainerType()

Specified by:

isContainerType in class ResolvedType

Returns:

True if type represented is a container type; this includes array, Map and Collection types.

isCollectionLikeType

public boolean isCollectionLikeType()

Specified by:

isCollectionLikeType in class ResolvedType

Returns:

True if type is either true Collection type, or something similar (meaning it has at least one type parameter, which describes type of contents)

isMapLikeType

public boolean isMapLikeType()

Specified by:

isMapLikeType in class ResolvedType

Returns:

True if type is either true Map type, or something similar (meaning it has at least two type parameter; first one describing key type, second value type)

useStaticType

public final boolean useStaticType()

Accessor for checking whether handlers for dealing with values of this type should use static typing (as opposed to dynamic typing). Note that while value of 'true' does mean that static typing is to be used, value of 'false' may still be overridden by other settings.

Since:

2.2

hasGenericTypes

public boolean hasGenericTypes()

Specified by:

hasGenericTypes in class ResolvedType

getKeyType

public JavaType getKeyType()

Specified by:

getKeyType in class ResolvedType

getContentType

public JavaType getContentType()

Specified by:

getContentType in class ResolvedType

containedTypeCount

public int containedTypeCount()

Specified by:

containedTypeCount in class ResolvedType

containedType

public JavaType containedType(int index)

Specified by:

containedType in class ResolvedType

containedTypeName

public String containedTypeName(int index)

Specified by:

containedTypeName in class ResolvedType

getValueHandler

public <T> T getValueHandler()

Method for accessing value handler associated with this type, if any

getTypeHandler

public <T> T getTypeHandler()

Method for accessing type handler associated with this type, if any

getGenericSignature

public String getGenericSignature()

Method for accessing signature that contains generic type information, in form compatible with JVM 1.5 as per JLS. It is a superset of getErasedSignature(), in that generic information can be automatically removed if necessary (just remove outermost angle brackets along with content inside)

getGenericSignature

public abstract StringBuilder getGenericSignature(StringBuilder sb)

Parameters:

sb - StringBuilder to append signature to

Returns:

StringBuilder that was passed in; returned to allow call chaining

getErasedSignature

public String getErasedSignature()

Method for accessing signature without generic type information, in form compatible with all versions of JVM, and specifically used for type descriptions when generating byte code.

getErasedSignature

public abstract StringBuilder getErasedSignature(StringBuilder sb)

Method for accessing signature without generic type information, in form compatible with all versions of JVM, and specifically used for type descriptions when generating byte code.

Parameters:

sb - StringBuilder to append signature to

Returns:

StringBuilder that was passed in; returned to allow call chaining

_assertSubclass

protected void _assertSubclass(Class<?> subclass,
                   Class<?> superClass)

toString

public abstract String toString()

Overrides:

toString in class Object

equals

public abstract boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public final int hashCode()

Overrides:

hashCode in class Object