Package org.perfectable.introspection.type

Class TypeVariableView<D extends GenericDeclaration>

java.lang.Object

org.perfectable.introspection.type.TypeView

org.perfectable.introspection.type.TypeVariableView<D>

Type Parameters:

D - Type declaring this variable

public final class TypeVariableView<D extends GenericDeclaration>
extends TypeView

TypeView that handles TypeVariable.

Nested Class Summary

Nested classes/interfaces inherited from class org.perfectable.introspection.type.TypeView

TypeView.PartialVisitor<T>, TypeView.Visitor<T>

Field Summary

Fields

Modifier and Type	Field	Description
protected T	type

Method Summary

Modifier and Type	Method	Description
ArrayTypeView	asArray()	Deprecated. the type system already knows this is a type variable, and this call will fail
ClassView<?>	asClass()	Deprecated. the type system already knows this is a type variable, and this call will fail
ParameterizedTypeView	asParameterized()	Deprecated. the type system already knows this is a type variable, and this call will fail
TypeVariableView<?>	asVariable()	Deprecated. the type system already knows this is a variable, and this call does not change the type
WildcardTypeView	asWildcard()	Deprecated. the type system already knows this is a type variable, and this call will fail
boolean	equals(Object obj)
Class<?>	erasure()	Finds exact class that would be erasure of wrapped type.
int	hashCode()
boolean	isSubTypeOf(TypeView other)	Tests if type wrapped in this view is subtype of the provided one.
static <D extends GenericDeclaration> TypeVariableView<D>	of(TypeVariable<D> variable)	Creates view over provided type.
String	toString()
T	unwrap()	Extracts native type from this view.
Collection<TypeView>	upperBounds()	Extracts upper bounds for this variable.
<T> T	visit(TypeView.Visitor<T> visitor)	Visitor patter method dispatching method.

Methods inherited from class org.perfectable.introspection.type.TypeView

isInstance, isProperSubtypeOf, isProperSubtypeOf, isProperSupertypeOf, isProperSupertypeOf, isSubTypeOf, isSuperTypeOf, isSuperTypeOf, of, of, of, of, of, ofParameterOf, ofTypeOf, ofTypeParameterOf, resolve, resolve

Methods inherited from class java.lang.Object

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

Field Detail

type

protected final T extends Type type

Method Detail

of

public static <D extends GenericDeclaration> TypeVariableView<D> of(TypeVariable<D> variable)

Creates view over provided type.

Type Parameters:

D - element type that is declaring this variable

Parameters:

variable - construct to wrap

Returns:

view wrapping specified type

erasure

public Class<?> erasure()

Description copied from class: TypeView

Finds exact class that would be erasure of wrapped type.

This method is implemented according to JSL section 4.6 with following extensions:

• Erasure of wildcard type is erasure of its leftmost upper bound, or Object if there isn't one

These extensions are needed, because these types are cannot be used in declaration, but can be obtained by reflections.

Specified by:

erasure in class TypeView

Returns:

erasure of wrapped type

upperBounds

public Collection<TypeView> upperBounds()

Extracts upper bounds for this variable.

Realizations of this variable must extend/implement all specified types.

In actual code, there can be only one upper bound, it is impossible to declare multiple bounds. But synthetic types can have multiple as reflection system supports it.

If variable has no upper bound, this method will return singleton collection with Object class. This is following contract in TypeVariable.getBounds(), which will return singleton array with Object class.

Returns:

upper bounds of this variable, wrapped in TypeView

asParameterized

@Deprecated
public ParameterizedTypeView asParameterized()
                                      throws IllegalStateException

Deprecated.

the type system already knows this is a type variable, and this call will fail

Always throws IllegalStateException, because it is statically provable that this instance cannot be converted to parameterized type.

Specified by:

asParameterized in class TypeView

Returns:

never

Throws:

IllegalStateException - always

asClass

@Deprecated
public ClassView<?> asClass()
                     throws IllegalStateException

Deprecated.

the type system already knows this is a type variable, and this call will fail

Always throws IllegalStateException, because it is statically provable that this instance cannot be converted to class view.

Specified by:

asClass in class TypeView

Returns:

never

Throws:

IllegalStateException - always

asVariable

@Deprecated
public TypeVariableView<?> asVariable()

Deprecated.

the type system already knows this is a variable, and this call does not change the type

Try to cast wrapped type to TypeVariable.

This method is useful if you know that underlying type is Class, then this is just a casting.

For any other type, this throws IllegalStateException, because nothing else can be converted to type variable.

Specified by:

asVariable in class TypeView

Returns:

this, as this is already variable view

asWildcard

@Deprecated
public WildcardTypeView asWildcard()
                            throws IllegalStateException

Deprecated.

the type system already knows this is a type variable, and this call will fail

Always throws IllegalStateException, because it is statically provable that this instance cannot be converted to wildcard type.

Specified by:

asWildcard in class TypeView

Returns:

never

Throws:

IllegalStateException - always

asArray

@Deprecated
public ArrayTypeView asArray()
                      throws IllegalStateException

Deprecated.

the type system already knows this is a type variable, and this call will fail

Always throws IllegalStateException, because it is statically provable that this instance cannot be converted to array type.

Specified by:

asArray in class TypeView

Returns:

never

Throws:

IllegalStateException - always

isSubTypeOf

public boolean isSubTypeOf(TypeView other)

Description copied from class: TypeView

Tests if type wrapped in this view is subtype of the provided one.

This method tries to adhere to the spirit of subtyping: it answers the question: Having reference of type T, can value of type S be always assigned to it?

Subtyping is precisely defined for types that can be declared in source, but there are more types that can be constructed or extracted via reflections. This method follows JLS section 4.10 for every aspect it declares, but also defines sensible rule for subtyping wildcards: wildcard is a supertype of its lower bounds, i.e. ? super CharStream is supertype of CharStream and

Specified by:

isSubTypeOf in class TypeView

Parameters:

other - type to test subtype relation against

Returns:

true if this type is subtype of provided argument

visit

public <T> T visit(TypeView.Visitor<T> visitor)

Description copied from class: TypeView

Visitor patter method dispatching method.

This method calls specific method on provided visitor, depending on actual implementation of this type.

It will return whatever the method returns.

Specified by:

visit in class TypeView

Type Parameters:

T - type returned by visitor method

Parameters:

visitor - method target

Returns:

same result as visitors method.

unwrap

public final T unwrap()

Description copied from class: TypeView

Extracts native type from this view.

This is inverse operation from TypeView.of(Type)

Specified by:

unwrap in class TypeView

Returns:

type that this view was for

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object