org.junit.platform.commons.support

Class ReflectionSupport

java.lang.Object

org.junit.platform.commons.support.ReflectionSupport

@API(status=MAINTAINED,
     since="1.0")
public final class ReflectionSupport
extends java.lang.Object

Common reflection and classpath scanning support.

Since:

1.0

Method Summary

Modifier and Type	Method and Description
static java.util.List<java.lang.Class<?>>	findAllClassesInClasspathRoot(java.net.URI root, java.util.function.Predicate<java.lang.Class<?>> classTester, java.util.function.Predicate<java.lang.String> classNameFilter) Find all classes of the supplied root URI that match the specified classTester and classNameFilter predicates.
static java.util.List<java.lang.Class<?>>	findAllClassesInPackage(java.lang.String basePackageName, java.util.function.Predicate<java.lang.Class<?>> classTester, java.util.function.Predicate<java.lang.String> classNameFilter) Find all classes of the supplied basePackageName that match the specified classTester and classNameFilter predicates.
static java.util.Optional<java.lang.reflect.Method>	findMethod(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.Class<?>... parameterTypes) Find the first Method of the supplied class or interface that meets the specified criteria, 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.
static java.util.Optional<java.lang.reflect.Method>	findMethod(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.String parameterTypeNames) Find the first Method of the supplied class or interface that meets the specified criteria, 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.
static java.util.List<java.lang.reflect.Method>	findMethods(java.lang.Class<?> clazz, java.util.function.Predicate<java.lang.reflect.Method> predicate, HierarchyTraversalMode traversalMode) Find all methods of the supplied class or interface that match the specified predicate.
static java.util.List<java.lang.Class<?>>	findNestedClasses(java.lang.Class<?> clazz, java.util.function.Predicate<java.lang.Class<?>> predicate) Find all nested classes of the given class conforming to the given predicate.
static java.lang.Object	invokeMethod(java.lang.reflect.Method method, java.lang.Object target, java.lang.Object... args) Invoke the supplied method, making it accessible if necessary and masking any checked exception as an unchecked exception.
static java.util.Optional<java.lang.Class<?>>	loadClass(java.lang.String name) Load a class by its primitive name or fully qualified name, using the default ClassLoader.
static <T> T	newInstance(java.lang.Class<T> clazz, java.lang.Object... args) Create a new instance of the specified Class by invoking the constructor whose argument list matches the types of the supplied arguments.

Methods inherited from class java.lang.Object

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

Method Detail

loadClass

public static java.util.Optional<java.lang.Class<?>> loadClass(java.lang.String name)

Load a class by its primitive name or fully qualified name, using the default ClassLoader.

Class names for arrays may be specified using either the JVM's internal String representation (e.g., [[I for int[][], [Lava.lang.String; for java.lang.String[], etc.) or source code syntax (e.g., int[][], java.lang.String[], etc.).

Parameters:

name - the name of the class to load; never null or blank

Returns:

an Optional containing the loaded class; never null but potentially empty if no such class could be loaded

findAllClassesInClasspathRoot

public static java.util.List<java.lang.Class<?>> findAllClassesInClasspathRoot(java.net.URI root,
                                                                               java.util.function.Predicate<java.lang.Class<?>> classTester,
                                                                               java.util.function.Predicate<java.lang.String> classNameFilter)

Find all classes of the supplied root URI that match the specified classTester and classNameFilter predicates.

Parameters:

root - the root URI to start scanning

classTester - the class type filter; never null

classNameFilter - the class name filter; never null

Returns:

an immutable list of all such classes found; never null but potentially empty

findAllClassesInPackage

public static java.util.List<java.lang.Class<?>> findAllClassesInPackage(java.lang.String basePackageName,
                                                                         java.util.function.Predicate<java.lang.Class<?>> classTester,
                                                                         java.util.function.Predicate<java.lang.String> classNameFilter)

Find all classes of the supplied basePackageName that match the specified classTester and classNameFilter predicates.

Parameters:

basePackageName - the base package name to start scanning

classTester - the class type filter; never null

classNameFilter - the class name filter; never null

Returns:

an immutable list of all such classes found; never null but potentially empty

newInstance

public static <T> T newInstance(java.lang.Class<T> clazz,
                                java.lang.Object... args)

Create a new instance of the specified Class by invoking the constructor whose argument list matches the types of the supplied arguments.

The constructor will be made accessible if necessary, and any checked exception will be masked as an unchecked exception.

Parameters:

clazz - the class to instantiate; never null

args - the arguments to pass to the constructor none of which may be null

Returns:

the new instance

See Also:

ExceptionUtils.throwAsUncheckedException(Throwable)

invokeMethod

public static java.lang.Object invokeMethod(java.lang.reflect.Method method,
                                            java.lang.Object target,
                                            java.lang.Object... args)

Invoke the supplied method, making it accessible if necessary and masking any checked exception as an unchecked exception.

Parameters:

method - the method to invoke; never null

target - the object on which to invoke the method; may be null if the method is static

args - the arguments to pass to the method

Returns:

the value returned by the method invocation or null if the return type is void

See Also:

ExceptionUtils.throwAsUncheckedException(Throwable)

findMethod

public static java.util.Optional<java.lang.reflect.Method> findMethod(java.lang.Class<?> clazz,
                                                                      java.lang.String methodName,
                                                                      java.lang.String parameterTypeNames)

Find the first Method of the supplied class or interface that meets the specified criteria, 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.

Parameters:

clazz - the class or interface in which to find the method; never null

methodName - the name of the method to find; never null or empty

parameterTypeNames - the fully qualified names of the types of parameters accepted by the method, if any, provided as a comma-separated list

Returns:

an Optional containing the method found; never null but potentially empty if no such method could be found

See Also:

findMethod(Class, String, Class...)

findMethod

public static java.util.Optional<java.lang.reflect.Method> findMethod(java.lang.Class<?> clazz,
                                                                      java.lang.String methodName,
                                                                      java.lang.Class<?>... parameterTypes)

Find the first Method of the supplied class or interface that meets the specified criteria, 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.

Parameters:

clazz - the class or interface in which to find the method; never null

methodName - the name of the method to find; never null or empty

parameterTypes - the types of parameters accepted by the method, if any; never null

Returns:

an Optional containing the method found; never null but potentially empty if no such method could be found

See Also:

findMethod(Class, String, String)

findMethods

public static java.util.List<java.lang.reflect.Method> findMethods(java.lang.Class<?> clazz,
                                                                   java.util.function.Predicate<java.lang.reflect.Method> predicate,
                                                                   HierarchyTraversalMode traversalMode)

Find all methods of the supplied class or interface that match the specified predicate.

The results will not contain instance methods that are overridden or static methods that are hidden.

If you're are looking for methods annotated with a certain annotation type, consider using AnnotationSupport.findAnnotatedMethods(Class, Class, HierarchyTraversalMode).

Parameters:

clazz - the class or interface in which to find the methods; never null

predicate - the method filter; never null

traversalMode - the hierarchy traversal mode; never null

Returns:

an immutable list of all such methods found; never null but potentially empty

findNestedClasses

public static java.util.List<java.lang.Class<?>> findNestedClasses(java.lang.Class<?> clazz,
                                                                   java.util.function.Predicate<java.lang.Class<?>> predicate)

Find all nested classes of the given class conforming to the given predicate.

Parameters:

clazz - the class to be searched; never null

predicate - the predicate against which the list of nested classes is checked; never null

Returns:

an immutable list of all such classes found; never null but potentially empty