@API(status=INTERNAL, since="1.0") public final class ReflectionUtils extends Object
These utilities are intended solely for usage within the JUnit framework itself. Any usage by external parties is not supported. Use at your own risk!
Some utilities are published via the maintained ReflectionSupport
class.
ReflectionSupport
Modifier and Type | Class and Description |
---|---|
static class |
ReflectionUtils.HierarchyTraversalMode
Modes in which a hierarchy can be traversed — for example, when
searching for methods or fields within a class hierarchy.
|
Modifier and Type | Method and Description |
---|---|
static List<Class<?>> |
findAllClassesInClasspathRoot(URI root,
ClassFilter classFilter) |
static List<Class<?>> |
findAllClassesInClasspathRoot(URI root,
Predicate<Class<?>> classFilter,
Predicate<String> classNameFilter) |
static List<Class<?>> |
findAllClassesInModule(String moduleName,
ClassFilter classFilter) |
static List<Class<?>> |
findAllClassesInModule(String moduleName,
Predicate<Class<?>> classFilter,
Predicate<String> classNameFilter) |
static List<Class<?>> |
findAllClassesInPackage(String basePackageName,
ClassFilter classFilter) |
static List<Class<?>> |
findAllClassesInPackage(String basePackageName,
Predicate<Class<?>> classFilter,
Predicate<String> classNameFilter) |
static List<Constructor<?>> |
findConstructors(Class<?> clazz,
Predicate<Constructor<?>> predicate)
Find all constructors in the supplied class that match the supplied predicate.
|
static List<Field> |
findFields(Class<?> clazz,
Predicate<Field> predicate,
ReflectionUtils.HierarchyTraversalMode traversalMode)
Find all fields of the supplied class or interface
that match the specified
predicate . |
static Optional<Method> |
findMethod(Class<?> clazz,
String methodName,
Class<?>... parameterTypes) |
static Optional<Method> |
findMethod(Class<?> clazz,
String methodName,
String parameterTypeNames) |
static List<Method> |
findMethods(Class<?> clazz,
Predicate<Method> predicate)
Find all methods of the supplied class or interface
that match the specified
predicate , using top-down search semantics
within the type hierarchy. |
static List<Method> |
findMethods(Class<?> clazz,
Predicate<Method> predicate,
ReflectionUtils.HierarchyTraversalMode traversalMode) |
static List<Class<?>> |
findNestedClasses(Class<?> clazz,
Predicate<Class<?>> predicate) |
static Set<Class<?>> |
getAllAssignmentCompatibleClasses(Class<?> clazz)
Return all classes and interfaces that can be used as assignment types
for instances of the specified
Class , including itself. |
static Set<Path> |
getAllClasspathRootDirectories() |
static <T> Constructor<T> |
getDeclaredConstructor(Class<T> clazz)
Get the sole declared
Constructor for the supplied class. |
static String |
getFullyQualifiedMethodName(Class<?> clazz,
String methodName,
Class<?>... parameterTypes)
Build the fully qualified method name for the method described by the
supplied class, method name, and parameter types.
|
static Optional<Object> |
getOutermostInstance(Object inner,
Class<?> requiredType)
Get the outermost instance of the required type, searching recursively
through enclosing instances.
|
static Class<?> |
getWrapperType(Class<?> type)
Get the wrapper type for the supplied primitive type.
|
static Object |
invokeMethod(Method method,
Object target,
Object... args) |
static boolean |
isAbstract(Class<?> clazz) |
static boolean |
isAbstract(Member member) |
static boolean |
isArray(Object obj)
Determine if the supplied object is an array.
|
static boolean |
isAssignableTo(Object obj,
Class<?> targetType)
Determine if the supplied object can be assigned to the supplied target
type for the purpose of reflective method invocations.
|
static boolean |
isInnerClass(Class<?> clazz)
Determine if the supplied class is an inner class (i.e., a
non-static member class).
|
static boolean |
isMethodPresent(Class<?> clazz,
Predicate<Method> predicate)
|
static boolean |
isNotPrivate(Member member) |
static boolean |
isNotStatic(Member member) |
static boolean |
isPrivate(Class<?> clazz) |
static boolean |
isPrivate(Member member) |
static boolean |
isPublic(Class<?> clazz) |
static boolean |
isPublic(Member member) |
static boolean |
isStatic(Class<?> clazz) |
static boolean |
isStatic(Member member) |
static Optional<Class<?>> |
loadClass(String name) |
static Optional<Class<?>> |
loadClass(String name,
ClassLoader classLoader)
Load a class by its primitive name or fully qualified name,
using the supplied
ClassLoader . |
static <T extends AccessibleObject> |
makeAccessible(T object) |
static <T> T |
newInstance(Class<T> clazz,
Object... args) |
static <T> T |
newInstance(Constructor<T> constructor,
Object... args)
Create a new instance of type
T by invoking the supplied constructor
with the supplied arguments. |
static String[] |
parseFullyQualifiedMethodName(String fullyQualifiedMethodName)
Parse the supplied fully qualified method name into a 3-element
String[] with the following content. |
static <T> Optional<Object> |
readFieldValue(Class<T> clazz,
String fieldName,
T instance)
Read the value of a potentially inaccessible or nonexistent field.
|
static Optional<Object> |
readFieldValue(Field field)
Read the value of a potentially inaccessible static field.
|
static <T> Optional<Object> |
readFieldValue(Field field,
T instance)
Read the value of a potentially inaccessible field.
|
static boolean |
returnsVoid(Method method) |
public static boolean isPublic(Class<?> clazz)
public static boolean isPublic(Member member)
public static boolean isPrivate(Class<?> clazz)
public static boolean isPrivate(Member member)
public static boolean isNotPrivate(Member member)
public static boolean isAbstract(Class<?> clazz)
public static boolean isAbstract(Member member)
public static boolean isStatic(Class<?> clazz)
public static boolean isStatic(Member member)
public static boolean isNotStatic(Member member)
public static boolean isInnerClass(Class<?> clazz)
Technically speaking (i.e., according to the Java Language
Specification), "an inner class may be a non-static member class, a
local class, or an anonymous class." However, this method does not
return true
for a local or anonymous class.
clazz
- the class to check; never null
true
if the class is an inner classpublic static boolean returnsVoid(Method method)
public static boolean isArray(Object obj)
obj
- the object to test; potentially null
true
if the object is an arraypublic static boolean isAssignableTo(Object obj, Class<?> targetType)
In contrast to Class.isInstance(Object)
, this method returns
true
if the target type represents a primitive type whose
wrapper matches the supplied object's type. In addition, this method
also supports
widening conversions for primitive types and their corresponding
wrapper types.
If the supplied object is null
and the supplied type does not
represent a primitive type, this method returns true
.
obj
- the object to test for assignment compatibility; potentially null
targetType
- the type to check against; never null
true
if the object is assignment compatibleClass.isInstance(Object)
,
Class.isAssignableFrom(Class)
public static Class<?> getWrapperType(Class<?> type)
type
- the primitive type for which to retrieve the wrapper typenull
if the
supplied type is null
or not a primitive typepublic static <T> T newInstance(Constructor<T> constructor, Object... args)
T
by invoking the supplied constructor
with the supplied arguments.
The constructor will be made accessible if necessary, and any checked exception will be masked as an unchecked exception.
constructor
- the constructor to invoke; never null
args
- the arguments to pass to the constructornull
newInstance(Class, Object...)
,
ExceptionUtils.throwAsUncheckedException(Throwable)
public static <T> Optional<Object> readFieldValue(Class<T> clazz, String fieldName, T instance)
If the field does not exist, an exception occurs while reading it, or
the value of the field is null
, an empty Optional
is
returned.
clazz
- the class where the field is declared; never null
fieldName
- the name of the field; never null
or emptyinstance
- the instance from where the value is to be read; may
be null
for a static fieldreadFieldValue(Field)
,
readFieldValue(Field, Object)
public static Optional<Object> readFieldValue(Field field)
If an exception occurs while reading the field or if the value of the
field is null
, an empty Optional
is returned.
field
- the field to read; never null
readFieldValue(Field, Object)
,
readFieldValue(Class, String, Object)
public static <T> Optional<Object> readFieldValue(Field field, T instance)
If an exception occurs while reading the field or if the value of the
field is null
, an empty Optional
is returned.
field
- the field to read; never null
instance
- the instance from which the value is to be read; may
be null
for a static fieldreadFieldValue(Field)
,
readFieldValue(Class, String, Object)
public static Optional<Class<?>> loadClass(String name)
ReflectionSupport.loadClass(String)
public static Optional<Class<?>> loadClass(String name, ClassLoader classLoader)
ClassLoader
.
See ReflectionSupport.loadClass(String)
for details on support for class names for arrays.
name
- the name of the class to load; never null
or blankclassLoader
- the ClassLoader
to use; never null
loadClass(String)
public static String getFullyQualifiedMethodName(Class<?> clazz, String methodName, Class<?>... parameterTypes)
clazz
- the class that declares the method; never null
methodName
- the name of the method; never null
or blankparameterTypes
- the parameter types of the method; may be null
or emptynull
public static String[] parseFullyQualifiedMethodName(String fullyQualifiedMethodName)
String[]
with the following content.
0
: the fully qualified class name1
: the name of the method2
: a comma-separated list of parameter types, or a
blank string if the method does not declare any formal parametersfullyQualifiedMethodName
- a fully qualified method name,
never null
or blankpublic static Optional<Object> getOutermostInstance(Object inner, Class<?> requiredType)
If the supplied inner object is of the required type, it will simply be returned.
inner
- the inner object from which to begin the search; never null
requiredType
- the required type of the outermost instance; never null
Optional
containing the outermost instance; never null
but potentially emptypublic static List<Class<?>> findAllClassesInClasspathRoot(URI root, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)
public static List<Class<?>> findAllClassesInClasspathRoot(URI root, ClassFilter classFilter)
public static List<Class<?>> findAllClassesInPackage(String basePackageName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)
public static List<Class<?>> findAllClassesInPackage(String basePackageName, ClassFilter classFilter)
public static List<Class<?>> findAllClassesInModule(String moduleName, Predicate<Class<?>> classFilter, Predicate<String> classNameFilter)
ReflectionSupport.findAllClassesInModule(String, Predicate, Predicate)
public static List<Class<?>> findAllClassesInModule(String moduleName, ClassFilter classFilter)
public static List<Class<?>> findNestedClasses(Class<?> clazz, Predicate<Class<?>> predicate)
public static <T> Constructor<T> getDeclaredConstructor(Class<T> clazz)
Constructor
for the supplied class.
Throws a PreconditionViolationException
if the supplied
class declares more than one constructor.
clazz
- the class to get the constructor fornull
Class.getDeclaredConstructors()
public static List<Constructor<?>> findConstructors(Class<?> clazz, Predicate<Constructor<?>> predicate)
clazz
- the class in which to search for constructors; never null
predicate
- the predicate to use to test for a match; never null
null
but potentially emptypublic static List<Field> findFields(Class<?> clazz, Predicate<Field> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)
predicate
.
The results will not contain fields that are hidden.
clazz
- the class or interface in which to find the fields; never null
predicate
- the field filter; never null
traversalMode
- the hierarchy traversal mode; never null
null
but potentially emptypublic static boolean isMethodPresent(Class<?> clazz, Predicate<Method> predicate)
Method
matching the supplied Predicate
is present within the type hierarchy of the specified class, beginning
with the specified class or interface and traversing up the type
hierarchy until such a method is found or the type hierarchy is exhausted.clazz
- the class or interface in which to find the method; never
null
predicate
- the predicate to use to test for a match; never
null
true
if such a method is presentfindMethod(Class, String, String)
,
findMethod(Class, String, Class...)
public static Optional<Method> findMethod(Class<?> clazz, String methodName, String parameterTypeNames)
public static Optional<Method> findMethod(Class<?> clazz, String methodName, Class<?>... parameterTypes)
public static List<Method> findMethods(Class<?> clazz, Predicate<Method> predicate)
predicate
, using top-down search semantics
within the type hierarchy.
The results will not contain instance methods that are overridden
or static
methods that are hidden.
clazz
- the class or interface in which to find the methods; never null
predicate
- the method filter; never null
null
ReflectionUtils.HierarchyTraversalMode.TOP_DOWN
,
findMethods(Class, Predicate, HierarchyTraversalMode)
public static List<Method> findMethods(Class<?> clazz, Predicate<Method> predicate, ReflectionUtils.HierarchyTraversalMode traversalMode)
public static <T extends AccessibleObject> T makeAccessible(T object)
public static Set<Class<?>> getAllAssignmentCompatibleClasses(Class<?> clazz)
Class
, including itself.clazz
- the Class
to look upClass.isAssignableFrom(java.lang.Class<?>)
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