JavaType (Jackson JSON Processor)

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

直接已知子类:

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.

字段概要

字段
限定符和类型	字段和说明
`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.

构造器概要

构造器
限定符构造器和说明

protected JavaType(Class<?> raw, int additionalHash)

构造器
限定符	构造器和说明
`protected`	`JavaType(Class<?> raw, int additionalHash)`

方法概要

方法
限定符和类型	方法和说明
`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)` 已过时。 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)`

从类继承的方法 java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - _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
    
    从以下版本开始:
    
    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
    
    从以下版本开始:
    
    1.5
- 构造器详细资料
  - JavaType
```
protected JavaType(Class<?> raw,
        int additionalHash)
```
    参数:
    raw - "Raw" (type-erased) class for this type
    additionalHash - Additional hash code to use, in addition to hash code of the class name
- 方法详细资料
  - 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.
    
    返回:
    Newly created type instance
    从以下版本开始:
    
    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.
    
    返回:
    Newly created type instance
    从以下版本开始:
    
    1.7
  - withValueHandler
```
public JavaType withValueHandler(Object h)
```
    从以下版本开始:
    
    1.9
  - withContentValueHandler
```
public JavaType withContentValueHandler(Object h)
```
    从以下版本开始:
    
    1.9
  - setValueHandler
```
@Deprecated
public void setValueHandler(Object h)
```
    已过时。 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
    
    从以下版本开始:
    
    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.
    
    从以下版本开始:
    
    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)
```
    从以下版本开始:
    
    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()
```
    从以下版本开始:
    
    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()
```
    返回:
    True if type represented is a container type; this includes array, Map and Collection types.
  - isCollectionLikeType
```
public boolean isCollectionLikeType()
```
    返回:
    True if type is either true Collection type, or something similar (meaning it has at least one type parameter, which describes type of contents)
    从以下版本开始:
    
    1.8
  - isMapLikeType
```
public boolean isMapLikeType()
```
    返回:
    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)
    从以下版本开始:
    
    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).
    
    从以下版本开始:
    
    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.
    
    从以下版本开始:
    
    1.5
  - containedType
```
public JavaType containedType(int index)
```
    Method for accessing definitions of contained ("child") types.
    
    参数:
    index - Index of contained type to return
    
    返回:
    Contained type at index, or null if no such type exists (no exception thrown)
    从以下版本开始:
    
    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.
    
    参数:
    index - Index of contained type to return
    
    返回:
    Contained type at index, or null if no such type exists (no exception thrown)
    从以下版本开始:
    
    1.5
  - getValueHandler
```
public <T> T getValueHandler()
```
    Method for accessing value handler associated with this type, if any
    
    从以下版本开始:
    
    1.3
  - getTypeHandler
```
public <T> T getTypeHandler()
```
    Method for accessing type handler associated with this type, if any
    
    从以下版本开始:
    
    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.
    
    从以下版本开始:
    
    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)
    
    从以下版本开始:
    
    1.6
  - getGenericSignature
```
public abstract StringBuilder getGenericSignature(StringBuilder sb)
```
    参数:
    sb - StringBuilder to append signature to
    
    返回:
    StringBuilder that was passed in; returned to allow call chaining
    从以下版本开始:
    
    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.
    
    从以下版本开始:
    
    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.
    
    参数:
    sb - StringBuilder to append signature to
    
    返回:
    StringBuilder that was passed in; returned to allow call chaining
    从以下版本开始:
    
    1.6
  - _assertSubclass
```
protected void _assertSubclass(Class<?> subclass,
                   Class<?> superClass)
```
  - toString
```
public abstract String toString()
```
    覆盖:
    
    toString 在类中 Object
  - equals
```
public abstract boolean equals(Object o)
```
    覆盖:
    
    equals 在类中 Object
  - hashCode
```
public final int hashCode()
```
    覆盖:
    
    hashCode 在类中 Object

类 JavaType

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

_class

_hashCode

_valueHandler

_typeHandler

构造器详细资料

JavaType

方法详细资料

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