public class Types
Utilities for working with Java types.
Static Methods
<T>iterableOf(Object value)
public static Iterable<T> <T>iterableOf(Object value)
Returns an iterable for an input iterable or array value.
If the input value extends Iterable, it will just return the input value. Otherwise, it will return an iterable that can handle arrays of primitive and non-primitive component type.
Parameter | |
---|---|
Name | Description |
value |
Object iterable (extends Iterable) or array value |
Returns | |
---|---|
Type | Description |
Iterable<T> |
iterable |
<T>newInstance(Class<T> clazz)
public static T <T>newInstance(Class<T> clazz)
Creates a new instance of the given class by invoking its default constructor.
The given class must be public and must have a public default constructor, and must not be an array or an interface or be abstract. If an enclosing class, it must be static.
Parameter | |
---|---|
Name | Description |
clazz |
Class<T> |
Returns | |
---|---|
Type | Description |
T |
getArrayComponentType(Type array)
public static Type getArrayComponentType(Type array)
Returns the component type of the given array type, assuming #isArray(Type).
Return type will either be class, parameterized type, generic array type, or type variable, but not a wildcard type.
Parameter | |
---|---|
Name | Description |
array |
Type |
Returns | |
---|---|
Type | Description |
Type |
getBound(WildcardType wildcardType)
public static Type getBound(WildcardType wildcardType)
Returns the only bound of the given wildcard type.
Parameter | |
---|---|
Name | Description |
wildcardType |
WildcardType wildcard type |
Returns | |
---|---|
Type | Description |
Type |
only bound or |
getIterableParameter(Type iterableType)
public static Type getIterableParameter(Type iterableType)
Returns the type parameter of Iterable that is assignable from the given iterable type.
For example, for the type ArrayList<Integer>
-- or for a class that extends
ArrayList<Integer>
-- it will return Integer
.
Parameter | |
---|---|
Name | Description |
iterableType |
Type iterable type (must extend Iterable) |
Returns | |
---|---|
Type | Description |
Type |
type parameter, which may be any type |
getMapValueParameter(Type mapType)
public static Type getMapValueParameter(Type mapType)
Returns the value type parameter of Map that is assignable from the given map type.
For example, for the type Map<String, Integer>
-- or for a class that extends
Map<String, Integer>
-- it will return Integer
.
Parameter | |
---|---|
Name | Description |
mapType |
Type map type (must extend Map) |
Returns | |
---|---|
Type | Description |
Type |
type parameter, which may be any type |
getRawArrayComponentType(List<Type> context, Type componentType)
public static Class<?> getRawArrayComponentType(List<Type> context, Type componentType)
Returns the raw array component type to use -- for example for the first parameter of Array#newInstance(Class, int) -- for the given component type.
Parameters | |
---|---|
Name | Description |
context |
List<Type> context list, ordering from least specific to most specific type context, for example container class and then its field |
componentType |
Type array component type or |
Returns | |
---|---|
Type | Description |
Class<?> |
raw array component type |
getRawClass(ParameterizedType parameterType)
public static Class<?> getRawClass(ParameterizedType parameterType)
Returns the raw class for the given parameter type as defined in ParameterizedType#getRawType().
Parameter | |
---|---|
Name | Description |
parameterType |
ParameterizedType parameter type |
Returns | |
---|---|
Type | Description |
Class<?> |
raw class |
getSuperParameterizedType(Type type, Class<?> superClass)
public static ParameterizedType getSuperParameterizedType(Type type, Class<?> superClass)
Returns the parameterized type that is or extends the given type that matches the given super class.
For example, if the input type is HashMap<String,Integer>
and the input super class
is Map.class
, it will return the extended parameterized type Map, but which
retains the actual type information from the original HashMap
.
Parameters | |
---|---|
Name | Description |
type |
Type class or parameterized type |
superClass |
Class<?> super class |
Returns | |
---|---|
Type | Description |
ParameterizedType |
matching parameterized type or |
isArray(Type type)
public static boolean isArray(Type type)
Returns whether the given type is an array.
Parameter | |
---|---|
Name | Description |
type |
Type |
Returns | |
---|---|
Type | Description |
boolean |
isAssignableToOrFrom(Class<?> classToCheck, Class<?> anotherClass)
public static boolean isAssignableToOrFrom(Class<?> classToCheck, Class<?> anotherClass)
Returns whether a class is either assignable to or from another class.
Parameters | |
---|---|
Name | Description |
classToCheck |
Class<?> class to check |
anotherClass |
Class<?> another class |
Returns | |
---|---|
Type | Description |
boolean |
resolveTypeVariable(List<Type> context, TypeVariable<?> typeVariable)
public static Type resolveTypeVariable(List<Type> context, TypeVariable<?> typeVariable)
Resolves the actual type of the given type variable that comes from a field type based on the given context list.
In case the type variable can be resolved partially, it will return the partially resolved type variable.
Parameters | |
---|---|
Name | Description |
context |
List<Type> context list, ordering from least specific to most specific type context, for example container class and then its field |
typeVariable |
TypeVariable<?> type variable |
Returns | |
---|---|
Type | Description |
Type |
resolved or partially resolved actual type (type variable, class, parameterized type,
or generic array type, but not wildcard type) or |
toArray(Collection<?> collection, Class<?> componentType)
public static Object toArray(Collection<?> collection, Class<?> componentType)
Returns a new array of the given component type (possibly a Java primitive) that is a copy of the content of the given collection.
Parameters | |
---|---|
Name | Description |
collection |
Collection<?> collection |
componentType |
Class<?> component type (possibly a Java primitive) |
Returns | |
---|---|
Type | Description |
Object |
new array |