uk.co.strangeskies.reflection

Class Types

java.lang.Object

uk.co.strangeskies.reflection.Types

public final class Types
extends java.lang.Object

A collection of general utility methods relating to the Java type system. Some utilities related to more specific classes of type may be found in WildcardTypes, ParameterizedTypes, and ArrayTypes..

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Types.TypeParser A parser for Types, and various related types.

Method Summary

Modifier and Type	Method and Description
static <T> T	assign(java.lang.Object object, java.lang.Class<T> type) If a given object is assignable to a given raw type, it will be converted to that type.
static boolean	equals(java.lang.reflect.Type a, java.lang.reflect.Type b) Test whether two types are equal to one another.
static java.lang.reflect.Type	fromString(java.lang.String typeString) Create a Type instance from a parsed String.
static java.util.stream.Stream<java.lang.reflect.Type>	getAllMentionedBy(java.lang.reflect.Type type, java.util.function.Predicate<java.lang.reflect.Type> condition) Search through all types mentioned by a given type, whether by identity, or through bound relationships, type parameterizations, type intersections, or generic array components, and collect all types meeting a given condition.
static int	getArrayDimensions(java.lang.reflect.Type type) Determine the number of array dimensions exist on the given type.
static java.lang.reflect.Type	getComponentType(java.lang.reflect.Type type) Find the component type of the given type, if the given Type instance is an array Class or an instance of GenericArrayType.
static java.lang.Class<?>	getErasedType(java.lang.reflect.Type type) Get the erasure of the given type.
static java.lang.reflect.Type	getInnerComponentType(java.lang.reflect.Type type) Find the innermost component type of the given type, if the given Type instance is an array Class or an instance of GenericArrayType with any number of dimensions.
static java.util.stream.Stream<java.lang.reflect.Type>	getLowerBounds(java.lang.reflect.Type type) Find the lower bounds of a given type.
static Types.TypeParser	getParser() Get the default type parser.
static Types.TypeParser	getParser(Imports imports) Get a type parser with knowledge of the given imports.
static java.util.stream.Stream<java.lang.reflect.Type>	getUpperBounds(java.lang.reflect.Type type) Find the upper bounding classes and parameterized types of a given type.
static Visibility	getVisibility(java.lang.Class<?> type) Determine the visibility of the type
static boolean	isAbstract(java.lang.Class<?> rawType) Determine whether a given class is abstract.
static boolean	isAssignable(java.lang.reflect.Type from, java.lang.reflect.Type to) Determine if a given type, to, is assignable from another given type, from.
static boolean	isCastable(java.lang.reflect.Type from, java.lang.reflect.Type to) Determine if a given type, to, is legally castable from another given type, from.
static boolean	isContainedBy(java.lang.reflect.Type from, java.lang.reflect.Type to) Determine if the given type, from, contains the given type, to.
static boolean	isFinal(java.lang.Class<?> rawType) Determine whether a given class is final.
static boolean	isGeneric(java.lang.Class<?> type) Determine whether a Class represents a generic class or an array with a generic class as a component type.
static boolean	isInterface(java.lang.Class<?> rawType) Determine whether a given class is an interface.
static boolean	isLooseInvocationContextCompatible(java.lang.reflect.Type from, java.lang.reflect.Type to) Determine whether a given type, from, is compatible with a given type, to, within a loose invocation context.
static boolean	isRaw(java.lang.reflect.Type type) Determine whether a type is raw, i.e.
static boolean	isStatic(java.lang.Class<?> rawType) Determine whether a given class is static.
static boolean	isStrictInvocationContextCompatible(java.lang.reflect.Type from, java.lang.reflect.Type to) Determine whether a given type, from, is compatible with a given type, to, within a strict invocation context.
static boolean	isSubtype(java.lang.reflect.Type subtype, java.lang.reflect.Type supertype) Determine if a given type, supertype, is a subtype of another given type, subtype.
static java.lang.String	toString(java.lang.reflect.Type type) Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type.
static java.lang.String	toString(java.lang.reflect.Type type, Imports imports) Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type.
static java.lang.String	toString(java.lang.reflect.Type type, Imports imports, Isomorphism isomorphism) Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

isGeneric

public static boolean isGeneric(java.lang.Class<?> type)

Determine whether a Class represents a generic class or an array with a generic class as a component type.

Parameters:

type - the type we wish to classify

Returns:

true if the given class is generic or if a non-statically enclosing class is generic, false otherwise

isRaw

public static boolean isRaw(java.lang.reflect.Type type)

Determine whether a type is raw, i.e. a generic type without a parameterization.

Parameters:

type - the type we wish to classify

Returns:

true if the given class is raw or if a non-statically enclosing class is raw, false otherwise

getErasedType

public static java.lang.Class<?> getErasedType(java.lang.reflect.Type type)

Get the erasure of the given type.

Parameters:

type - The type of which we wish to determine the raw type.

Returns:

The raw type of the type represented by this TypeToken.

getUpperBounds

public static java.util.stream.Stream<java.lang.reflect.Type> getUpperBounds(java.lang.reflect.Type type)

Find the upper bounding classes and parameterized types of a given type.

Parameters:

type - The type whose bounds we wish to discover.

Returns:

The upper bounds of the given type.

getLowerBounds

public static java.util.stream.Stream<java.lang.reflect.Type> getLowerBounds(java.lang.reflect.Type type)

Find the lower bounds of a given type.

Parameters:

type - The type whose bounds we wish to discover.

Returns:

The lower bounds of the given type, or null if no such bounds exist.

isAbstract

public static boolean isAbstract(java.lang.Class<?> rawType)

Determine whether a given class is abstract.

Parameters:

rawType - The type we wish to classify.

Returns:

True if the type is abstract, false otherwise.

isFinal

public static boolean isFinal(java.lang.Class<?> rawType)

Determine whether a given class is final.

Parameters:

rawType - The type we wish to classify.

Returns:

True if the type is final, false otherwise.

isInterface

public static boolean isInterface(java.lang.Class<?> rawType)

Determine whether a given class is an interface.

Parameters:

rawType - The type we wish to classify.

Returns:

True if the type is an interface, false otherwise.

getVisibility

public static Visibility getVisibility(java.lang.Class<?> type)

Determine the visibility of the type

Parameters:

type - the type whose visibility we wish to determine

Returns:

a Visibility object describing the type

isStatic

public static boolean isStatic(java.lang.Class<?> rawType)

Determine whether a given class is static.

Parameters:

rawType - The type we wish to classify.

Returns:

True if the type is static, false otherwise.

getComponentType

public static java.lang.reflect.Type getComponentType(java.lang.reflect.Type type)

Find the component type of the given type, if the given Type instance is an array Class or an instance of GenericArrayType.

Parameters:

type - The type of which we wish to determine the component type.

Returns:

The component type of the given type, if it is an array type, otherwise null.

getInnerComponentType

public static java.lang.reflect.Type getInnerComponentType(java.lang.reflect.Type type)

Find the innermost component type of the given type, if the given Type instance is an array Class or an instance of GenericArrayType with any number of dimensions.

Parameters:

type - The type of which we wish to determine the component type.

Returns:

The component type of the given type if it is an array type, otherwise null.

getArrayDimensions

public static int getArrayDimensions(java.lang.reflect.Type type)

Determine the number of array dimensions exist on the given type.

Parameters:

type - A type which may or may not be an array.

Returns:

The number of dimensions on the given type, or 0 if it is not an array type.

isCastable

public static boolean isCastable(java.lang.reflect.Type from,
                                 java.lang.reflect.Type to)

Determine if a given type, to, is legally castable from another given type, from.

Parameters:

from - The type from which we wish to determine castability.

to - The type to which we wish to determine castability.

Returns:

True if the types are castable, false otherwise.

assign

public static <T> T assign(java.lang.Object object,
                           java.lang.Class<T> type)

If a given object is assignable to a given raw type, it will be converted to that type. Generally this is an identity conversion, but for wrapped primitive types the extra step is taken to make conversions to which are consistent with widening primitive conversions.

Type Parameters:

T - the type to which we wish to assign

Parameters:

object - the type from which we wish to assign

type - the type to which we wish to assign

Returns:

true if the types are assignable, false otherwise

equals

public static boolean equals(java.lang.reflect.Type a,
                             java.lang.reflect.Type b)

Test whether two types are equal to one another.

Parameters:

a - the first type

b - the second type

Returns:

true if the two given types are equal, false otherwise

isContainedBy

public static boolean isContainedBy(java.lang.reflect.Type from,
                                    java.lang.reflect.Type to)

Determine if the given type, from, contains the given type, to. In other words, if either of the given types are wildcards, determine if every possible instantiation of to is also a valid instantiation of from. Or if neither type is a wildcard, determine whether both types are assignable to each other as per isSubtype(Type, Type).

Parameters:

from - the type within which we are determining containment

to - the type of which we are determining containment

Returns:

true if from contains to, false otherwise

isSubtype

public static boolean isSubtype(java.lang.reflect.Type subtype,
                                java.lang.reflect.Type supertype)

Determine if a given type, supertype, is a subtype of another given type, subtype. Or in other words, if supertype is a supertype of subtype. Types are considered assignable if they involve unchecked generic casts.

Parameters:

subtype - the type from which we wish to determine assignability

supertype - the type to which we wish to determine assignability

Returns:

true if the types are assignable, false otherwise

isAssignable

public static boolean isAssignable(java.lang.reflect.Type from,
                                   java.lang.reflect.Type to)

Determine if a given type, to, is assignable from another given type, from. Or in other words, if to is a supertype of from. Types are considered assignable if they involve unchecked generic casts.

Parameters:

from - the type from which we wish to determine assignability

to - the type to which we wish to determine assignability

Returns:

true if the types are assignable, false otherwise

isStrictInvocationContextCompatible

public static boolean isStrictInvocationContextCompatible(java.lang.reflect.Type from,
                                                          java.lang.reflect.Type to)

Determine whether a given type, from, is compatible with a given type, to, within a strict invocation context.

Types are considered so compatible if assignment is possible through application of the following conversions:

• an identity conversion (§5.1.1)
• a widening primitive conversion (§5.1.2)
• a widening reference conversion (§5.1.5)

Parameters:

from - The type from which to determine compatibility.

to - The type to which to determine compatibility.

Returns:

True if the type from is compatible with the type to, false otherwise.

isLooseInvocationContextCompatible

public static boolean isLooseInvocationContextCompatible(java.lang.reflect.Type from,
                                                         java.lang.reflect.Type to)

Determine whether a given type, from, is compatible with a given type, to, within a loose invocation context.

Types are considered so compatible if assignment is possible through application of the following conversions:

• an identity conversion
• a widening primitive conversion
• a widening reference conversion
• a boxing conversion, optionally followed by widening reference conversion
• an unboxing conversion, optionally followed by a widening primitive conversion

Parameters:

from - The type from which to determine compatibility.

to - The type to which to determine compatibility.

Returns:

True if the type from is compatible with the type to, false otherwise.

getAllMentionedBy

public static java.util.stream.Stream<java.lang.reflect.Type> getAllMentionedBy(java.lang.reflect.Type type,
                                                                                java.util.function.Predicate<java.lang.reflect.Type> condition)

Search through all types mentioned by a given type, whether by identity, or through bound relationships, type parameterizations, type intersections, or generic array components, and collect all types meeting a given condition.

Parameters:

type - The type to search for mentions which match the given condition.

condition - The condition to classify matching types.

Returns:

A set of all mentioned types matching the condition.

toString

public static java.lang.String toString(java.lang.reflect.Type type)

Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type.

Parameters:

type - The type for which we wish to determine a string representation.

Returns:

A canonical string representation of the given type.

toString

public static java.lang.String toString(java.lang.reflect.Type type,
                                        Imports imports)

Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type. Provided class and package imports allow the names of some classes to be output without full package qualification.

Parameters:

imports - classes and packages for which full package qualification may be omitted from output

type - the type for which we wish to determine a string representation

Returns:

A canonical string representation of the given type.

toString

public static java.lang.String toString(java.lang.reflect.Type type,
                                        Imports imports,
                                        Isomorphism isomorphism)

Give a canonical String representation of a given type, which is intended to be more easily human-readable than implementations of Object.toString() for certain implementations of Type. Provided class and package imports allow the names of some classes to be output without full package qualification.

Parameters:

imports - classes and packages for which full package qualification may be omitted from output

type - the type for which we wish to determine a string representation

isomorphism - a type to string isomorphic mapping to deal with recursion

Returns:

A canonical string representation of the given type.

fromString

public static java.lang.reflect.Type fromString(java.lang.String typeString)

Create a Type instance from a parsed String. Here infinitely recurring types are represented by, for example: java.util.List<java.lang.Number & java.lang.Comparable<? extends java.lang.Number & java.lang.Comparable<? extends java.lang.Number & java.lang.Comparable <...>>>> Where "..." would be substituted, recursively, with the parameterization of the an outer instance of the same raw class. TODO add clarity, and a proper description of how ambiguity is resolved here.

Parameters:

typeString - The String to parse.

Returns:

The type described by the String.

getParser

public static Types.TypeParser getParser()

Get the default type parser. All type names will need to be fully qualified to correctly parse.

Returns:

The default annotated type parser

getParser

public static Types.TypeParser getParser(Imports imports)

Get a type parser with knowledge of the given imports. Type names may omit full qualification if those types are imported according to the given imports.

Parameters:

imports - A list of imports the type parser should be aware of

Returns:

A type parser with knowledge of the given imports