Method Details

• findMethod

  public static Method findMethod(Class<?> cls, String methodName, Class<?>... parameterTypes) throws ExceptionInInitializerError

  Locates the method in the given class. Returns null if the method is not found. Throws an ExceptionInInitializerError if there is a problem locating the method as this is mainly called from static blocks.

  Parameters:

  cls - Class that contains the method

  methodName - The name of the method

  parameterTypes - The parameter types for the method.

  Returns:

  A reference to the method

  Throws:

  ExceptionInInitializerError - Wraps any exception in an ExceptionInInitializerError so this method can be called from a static initializer.

• getJavaFieldValue

  public static Object getJavaFieldValue(Object object, Field field) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException

  Returns the value of the java field.

  Uses getter if present, otherwise tries to access even private fields directly.

  Parameters:

  object - The object containing the field

  field - The field we want to get the value for

  Returns:

  The value of the field in the object

  Throws:

  InvocationTargetException - If the value could not be retrieved

  IllegalAccessException - If the value could not be retrieved

  IllegalArgumentException - If the value could not be retrieved

• getJavaFieldValue

  public static Object getJavaFieldValue(Object object, Field field, Class<?> propertyType) throws IllegalArgumentException, IllegalAccessException, InvocationTargetException

  Returns the value of the java field that is assignable to the property type.

  Uses getter if a getter for the correct return type is present, otherwise tries to access even private fields directly. If the java field is not assignable to the property type throws an IllegalArgumentException.

  Parameters:

  object - The object containing the field

  field - The field we want to get the value for

  propertyType - The type the field must be assignable to

  Returns:

  The value of the field in the object

  Throws:

  InvocationTargetException - If the value could not be retrieved

  IllegalAccessException - If the value could not be retrieved

  IllegalArgumentException - If the value could not be retrieved

• setJavaFieldValue

  public static void setJavaFieldValue(Object object, Field field, Object value) throws IllegalArgumentException

  Sets the value of a java field.

  Parameters:

  object - The object containing the field

  field - The field we want to set the value for

  value - The value to set

  Throws:

  IllegalArgumentException - If the value could not be assigned to the field

• convertPrimitiveType

  public static Class<?> convertPrimitiveType(Class<?> type)

  Converts the given primitive type to its boxed version.

  Parameters:

  type - the primitive type to convert

  Returns:

  the corresponding boxed type

• getPrimitiveDefaultValue

  public static Serializable getPrimitiveDefaultValue(Class<?> primitiveType)

  Gets default value for given primitiveType.

  Parameters:

  primitiveType - the primitive type

  Returns:

  the corresponding default value

• isSetter

  public static boolean isSetter(Method method)

  Checks whether the given method is a valid setter according to the JavaBeans Specification.

  Parameters:

  method - the method to check

  Returns:

  true if the method is a setter, false if not

• isSetterName

  public static boolean isSetterName(String methodName)

  Checks whether the given method name is a valid setter name according to the JavaBeans Specification.

  Parameters:

  methodName - the method name to check

  Returns:

  true if the method name is a setter name, false if not

• isGetterName

  public static boolean isGetterName(String methodName, boolean isBoolean)

  Checks whether the given method name is a valid getter name according to the JavaBeans Specification.

  Parameters:

  methodName - the method name to check

  isBoolean - whether the method is getter for boolean type

  Returns:

  true if the method name is a getter name, false if not

• isGetter

  public static boolean isGetter(Method method)

  Checks whether the given method is a valid getter according to JavaBeans Specification.

  Parameters:

  method - the method to check

  Returns:

  true if the method is a getter, false if not

• getGetterMethods

  public static Stream<Method> getGetterMethods(Class<?> type)

  Return all the getter methods from the given type.

  Any getter methods from Object are excluded.

  Parameters:

  type - the type to get getters from

  Returns:

  a stream of getter methods

• getSetterMethods

  public static Stream<Method> getSetterMethods(Class<?> type)

  Return all the setter methods from the given type.

  Parameters:

  type - the type to get setters from

  Returns:

  a stream of setter methods

• isNotObjectMethod

  public static boolean isNotObjectMethod(Method method)

  Returns whether the given method is NOT declared in Object .

  Parameters:

  method - the method to check

  Returns:

  true if method is NOT declared in Object, false if it is

• getPropertyName

  public static String getPropertyName(Method method)

  Parses the property name from the given getter or setter method.

  If the given method does not have a valid setter or getter name, this method may produce unexpected results.

  Parameters:

  method - the method to parse

  Returns:

  the name of the property

  See Also:

  • isSetter(Method)
  • isGetter(Method)

• getPropertyType

  public static Type getPropertyType(Method method)

  Returns property type from the given getter or setter method.

  Parameters:

  method - the method to inspect

  Returns:

  the property type

  See Also:

  • isSetter(Method)
  • isGetter(Method)

• createInstance

  public static <T> T createInstance(Class<T> cls)

  Creates an instance of the given class with a no-arg constructor.

  Catches all exceptions which might occur and wraps them in a IllegalArgumentException with a descriptive error message hinting of what might be wrong with the class that could not be instantiated.

  Type Parameters:

  T - the instance type

  Parameters:

  cls - the class to instantiate

  Returns:

  an instance of the class

• createProxyInstance

  public static <T> T createProxyInstance(Class<T> proxyClass, Class<?> originalClass)

  Creates an instance of the given proxyClass with no-arg constructor.

  Catches all exceptions which might occur and wraps them in a IllegalArgumentException with a descriptive error message hinting of what might be wrong with the class that could not be instantiated. Descriptive message is derived based on the information about the originalClass.

  Type Parameters:

  T - type of a proxy class

  Parameters:

  proxyClass - the proxy class to instantiate

  originalClass - the class that is used to determine exception description, if creation fails

  Returns:

  instance of a proxyClass

  Throws:

  IllegalArgumentException - if class instance creation fails

• convertInstantiationException

  public static IllegalArgumentException convertInstantiationException(Exception exception, Class<?> clazz)

  Helper to handle all exceptions which might occur during class instantiation and returns an IllegalArgumentException with a descriptive error message hinting of what might be wrong with the class that could not be instantiated. Descriptive message is derived based on the information about the clazz.

  Parameters:

  exception - original exception

  clazz - instantiation target class

  Returns:

  an IllegalArgumentException with descriptive message

• checkClassAccessibility

  public static void checkClassAccessibility(Class<?> clazz)

  Makes a check whether the clazz is externally accessible for instantiation (e.g. it's not inner class (nested and not static) and is not a local class).

  Parameters:

  clazz - type to check

• createParameterizedType

  public static Type createParameterizedType(Class<?> rawType, Type subType)

  Creates a parameterized type, e.g. List<Bean>.

  Parameters:

  rawType - the raw type, e.g. List

  subType - the sub type, e.g. Bean

  Returns:

  a parameterized type

• getGenericInterfaceType

  public static Class<?> getGenericInterfaceType(Class<?> clazz, Class<?> interfaceType)

  Finds the Class type for the generic interface class extended by given class if exists.

  Parameters:

  clazz - class that should extend interface

  interfaceType - class type of interface to get generic for

  Returns:

  Class if found else null

• getGenericInterfaceTypes

  public static List<Class<?>> getGenericInterfaceTypes(Class<?> clazz, Class<?> interfaceType)

  Finds the Class type for all parameters defined by the generic interface class extended by given class if exists.

  Parameters:

  clazz - class that should extend interface

  interfaceType - class type of interface to get generic for

  Returns:

  List of Class if found else empty List, never null

• getGetter

  public static Optional<Method> getGetter(Class<? extends Object> beanClass, String propertyName)

  Finds a getter for a property in a bean type.

  Parameters:

  beanClass - the bean type, not null

  propertyName - the property name, not null

  Returns:

  a getter method, or an empty optional if the bean type has no readable property with the provided name

• isCheckedException

  public static boolean isCheckedException(Class<?> exceptionClass)

  Checks if the given exception class represents a checked exception.

  Parameters:

  exceptionClass - the class to check

  Returns:

  true if the class represents a checked exception, false otherwise

• getFunctionalMethod

  public static Method getFunctionalMethod(Class<?> functionalClass)

  Get the functional interface method name defined for given interface class.

  Parameters:

  functionalClass - interface class to get the functional method for

  Returns:

  functional interface method

• getConstantIntValues

  public static List<Integer> getConstantIntValues(Class<?> clazz)

  Collect all the integer values for public static final constants found for the given class.

  Parameters:

  clazz - class to collect constants from

  Returns:

  list of all integer constants in class

• findCommonBaseType

  public static Class<?> findCommonBaseType(Class<?> a, Class<?> b)

  Finds the most specific class that both provided classes extend from.

  Parameters:

  a - one class to get the base type for, not null

  b - another class to get the base type for, not null

  Returns:

  the most specific base class, not null

  Throws:

  IllegalArgumentException - if a or b are interfaces or primitive types

• findClosestCommonClassLoaderAncestor

  public static Optional<ClassLoader> findClosestCommonClassLoaderAncestor(ClassLoader classLoaderA, ClassLoader classLoaderB)

  Finds the common ancestor of the two ClassLoaders. The class loaders themselves are acceptable ancestors; If they are equal, classLoaderA is returned. An empty optional is returned if the two class loaders aren't equal, no shared ancestor is found, or the implementation of the class loader treats bootstrap class loader as null when it is the parent of a class loaders (see ClassLoader.getParent().

  Parameters:

  classLoaderA - class loader A

  classLoaderB - class loader B

  Returns:

  a common ancestor both class loaders share, or an empty optional if there is no shared ancestor. Or if the implementation treats bootstrap loaders as null (as per ClassLoader.getParent()).

• hasAnnotation

  public static boolean hasAnnotation(AnnotatedElement element, String annotationFqn)

  Checks whether the element has annotation whose FQN is annotationFqn.

  Parameters:

  element - annotated element (field, method, etc.)

  annotationFqn - annotation FQN

  Returns:

  true is element has annotation whose FQN is annotationFqn, false otherwise

• hasAnnotationWithSimpleName

  public static boolean hasAnnotationWithSimpleName(AnnotatedElement element, String simpleName)

  Checks whether the element has annotation whose simple name is simpleName.

  Parameters:

  element - annotated element (field, method, etc.)

  simpleName - annotation simple name

  Returns:

  true is element has annotation whose simple name is simpleName, false otherwise

• getAnnotationMethodValue

  public static Object getAnnotationMethodValue(Annotation annotation, String methodName)

  Gets the annotation method return value.

  Parameters:

  annotation - the annotation

  methodName - the method name

  Returns:

  an optional value, or an empty optional if element has no annotation with required annotationFqn

• getAnnotation

  public static Optional<Annotation> getAnnotation(AnnotatedElement element, String annotationFqn)

  Gets annotation of element whose FQN is annotationFqn.

  Parameters:

  element - annotated element (field, method, etc.)

  annotationFqn - annotation FQN

  Returns:

  an optional annotation, or an empty optional if element has no annotation with required annotationFqn

• isInstantiableService

  public static boolean isInstantiableService(Class<?> clazz)

  Check if a class can be instantiated via its default constructor via reflection.

  Parameters:

  clazz - the class to check

  Returns:

  true if the class can be instantiated, otherwise false