JavaType (Jackson JSON Processor)

java.lang.Object
- org.codehaus.jackson.type.JavaType

Direct Known Subclasses:

TypeBase
```
public abstract class JavaType
extends Object
```
Base class for type token classes used both to contain information and as keys for deserializers.
Instances can (only) be constructed by TypeFactory.

Field Summary

Fields
Modifier and Type	Field and Description
`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`	`_hashCode`
`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)

Constructors
Modifier	Constructor and Description
`protected`	`JavaType(Class<?> raw, int additionalHash)`

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)` Method for accessing definitions of contained ("child") types.
`int`	`containedTypeCount()` Method for checking how many contained types this type has.
`String`	`containedTypeName(int index)` Method for accessing name of type variable in indicated position.
`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()` Method for accessing content type of this type, if type has such a thing: simple types do not, structured types do (like arrays, Collections and Maps)
`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()` Method for accessing key type for this type, assuming type has such a concept (only Map types do)
`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()` Method that can be used to find out if the type directly declares generic parameters (for its direct super-class and/or super-interfaces).
`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()`
`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)`
`void`	`setValueHandler(Object h)` Deprecated. Since 1.9, should not be used; instead, use `withContentTypeHandler` and `withContentValueHandler` methods.
`abstract String`	`toCanonical()` Method that can be used to serialize type into form from which it can be fully deserialized from at a later point (using `TypeFactory` from mapper package).
`abstract String`	`toString()`
`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.
`JavaType`	`withContentValueHandler(Object h)`
`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.
`JavaType`	`withValueHandler(Object h)`

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.
  - _hashCode
```
protected final int _hashCode
```
  - _valueHandler
```
protected 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.
    TODO: make final and possible promote to sub-classes
    
    Since:
    
    1.3
  - _typeHandler
```
protected 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.
    TODO: make final and possible promote to sub-classes
    
    Since:
    
    1.5
- Constructor Detail
  - JavaType
```
protected JavaType(Class<?> raw,
        int additionalHash)
```
    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
    Since:
    
    1.7
  - 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
    Since:
    
    1.7
  - withValueHandler
```
public JavaType withValueHandler(Object h)
```
    Since:
    
    1.9
  - withContentValueHandler
```
public JavaType withContentValueHandler(Object h)
```
    Since:
    
    1.9
  - setValueHandler
```
@Deprecated
public void setValueHandler(Object h)
```
    Deprecated. Since 1.9, should not be used; instead, use withContentTypeHandler and withContentValueHandler methods.
    
    Method for assigning handler to associate with this type; or if null passed, to remove such assignment
    
    Since:
    
    1.3
  - 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.
    
    Since:
    
    1.5
  - 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)
```
    Since:
    
    1.8
  - getRawClass
```
public final Class<?> getRawClass()
```
  - 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.
  - isAbstract
```
public boolean isAbstract()
```
  - isConcrete
```
public boolean isConcrete()
```
    Since:
    
    1.3
  - isThrowable
```
public boolean isThrowable()
```
  - isArrayType
```
public boolean isArrayType()
```
  - isEnumType
```
public final boolean isEnumType()
```
  - isInterface
```
public final boolean isInterface()
```
  - isPrimitive
```
public final boolean isPrimitive()
```
  - isFinal
```
public final boolean isFinal()
```
  - isContainerType
```
public abstract boolean isContainerType()
```
    Returns:
    True if type represented is a container type; this includes array, Map and Collection types.
  - isCollectionLikeType
```
public boolean isCollectionLikeType()
```
    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)
    Since:
    
    1.8
  - isMapLikeType
```
public boolean isMapLikeType()
```
    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)
    Since:
    
    1.8
  - hasGenericTypes
```
public boolean hasGenericTypes()
```
    Method that can be used to find out if the type directly declares generic parameters (for its direct super-class and/or super-interfaces).
    
    Since:
    
    1.6
  - getKeyType
```
public JavaType getKeyType()
```
    Method for accessing key type for this type, assuming type has such a concept (only Map types do)
  - getContentType
```
public JavaType getContentType()
```
    Method for accessing content type of this type, if type has such a thing: simple types do not, structured types do (like arrays, Collections and Maps)
  - containedTypeCount
```
public int containedTypeCount()
```
    Method for checking how many contained types this type has. Contained types are usually generic types, so that generic Maps have 2 contained types.
    
    Since:
    
    1.5
  - containedType
```
public JavaType containedType(int index)
```
    Method for accessing definitions of contained ("child") types.
    
    Parameters:
    index - Index of contained type to return
    
    Returns:
    Contained type at index, or null if no such type exists (no exception thrown)
    Since:
    
    1.5
  - containedTypeName
```
public String containedTypeName(int index)
```
    Method for accessing name of type variable in indicated position. If no name is bound, will use placeholders (derived from 0-based index); if no type variable or argument exists with given index, null is returned.
    
    Parameters:
    index - Index of contained type to return
    
    Returns:
    Contained type at index, or null if no such type exists (no exception thrown)
    Since:
    
    1.5
  - getValueHandler
```
public <T> T getValueHandler()
```
    Method for accessing value handler associated with this type, if any
    
    Since:
    
    1.3
  - getTypeHandler
```
public <T> T getTypeHandler()
```
    Method for accessing type handler associated with this type, if any
    
    Since:
    
    1.5
  - toCanonical
```
public abstract String toCanonical()
```
    Method that can be used to serialize type into form from which it can be fully deserialized from at a later point (using TypeFactory from mapper package). For simple types this is same as calling Class.getName(), but for structured types it may additionally contain type information about contents.
    
    Since:
    
    1.5
  - 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)
    
    Since:
    
    1.6
  - 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
    Since:
    
    1.6
  - 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.
    
    Since:
    
    1.6
  - 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
    Since:
    
    1.6
  - _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

Class JavaType

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

_class

_hashCode

_valueHandler

_typeHandler

Constructor Detail

JavaType

Method Detail

withTypeHandler

withContentTypeHandler

withValueHandler

withContentValueHandler

setValueHandler

narrowBy

forcedNarrowBy

widenBy

_narrow

_widen

narrowContentsBy

widenContentsBy

getRawClass

hasRawClass

isAbstract

isConcrete

isThrowable

isArrayType

isEnumType

isInterface

isPrimitive

isFinal

isContainerType

isCollectionLikeType

isMapLikeType

hasGenericTypes

getKeyType

getContentType

containedTypeCount

containedType

containedTypeName

getValueHandler

getTypeHandler

toCanonical

getGenericSignature

getGenericSignature

getErasedSignature

getErasedSignature

_assertSubclass

toString

equals

hashCode