Class JavaType

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 Details

    • _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 Details

    • 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 Details

    • 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(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(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