com.vaadin.flow.internal

Class ReflectTools

java.lang.Object

com.vaadin.flow.internal.ReflectTools

All Implemented Interfaces:

Serializable

public class ReflectTools
extends Object
implements Serializable

An util class with helpers for reflection operations. Used internally by Vaadin and should not be used by application developers. Subject to change at any time.

For internal use only. May be renamed or removed in a future release.

Since:

1.0

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ReflectTools()

Method Summary

Modifier and Type	Method and Description
static void	checkClassAccessibility(Class<?> clazz) Makes a check whether the clazz is externally accessible for instantiation (e.g.
static Class<?>	convertPrimitiveType(Class<?> type) Converts the given primitive type to its boxed version.
static <T> T	createInstance(Class<T> cls) Creates an instance of the given class with a no-arg constructor.
static Type	createParameterizedType(Class<?> rawType, Type subType) Creates a parameterized type, e.g.
static <T> T	createProxyInstance(Class<T> proxyClass, Class<?> originalClass) Creates an instance of the given proxyClass with no-arg constructor.
static Optional<ClassLoader>	findClosestCommonClassLoaderAncestor(ClassLoader classLoaderA, ClassLoader classLoaderB) Finds the common ancestor of the two ClassLoaders.
static Class<?>	findCommonBaseType(Class<?> a, Class<?> b) Finds the most specific class that both provided classes extend from.
static Method	findMethod(Class<?> cls, String methodName, Class<?>... parameterTypes) Locates the method in the given class.
static List<Integer>	getConstantIntValues(Class<?> clazz) Collect all the integer values for public static final constants found for the given class.
static Method	getFunctionalMethod(Class<?> functionalClass) Get the functional interface method name defined for given interface class.
static Class<?>	getGenericInterfaceType(Class<?> clazz, Class<?> interfaceType) Finds the Class type for the generic interface class extended by given class if exists.
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.
static Optional<Method>	getGetter(Class<? extends Object> beanClass, String propertyName) Finds a getter for a property in a bean type.
static Stream<Method>	getGetterMethods(Class<?> type) Return all the getter methods from the given type.
static Object	getJavaFieldValue(Object object, Field field) Returns the value of the java field.
static Object	getJavaFieldValue(Object object, Field field, Class<?> propertyType) Returns the value of the java field that is assignable to the property type.
static Serializable	getPrimitiveDefaultValue(Class<?> primitiveType) Gets default value for given primitiveType.
static String	getPropertyName(Method method) Parses the property name from the given getter or setter method.
static Type	getPropertyType(Method method) Returns property type from the given getter or setter method.
static Stream<Method>	getSetterMethods(Class<?> type) Return all the setter methods from the given type.
static boolean	isCheckedException(Class<?> exceptionClass) Checks if the given exception class represents a checked exception.
static boolean	isGetter(Method method) Checks whether the given method is a valid getter according to JavaBeans Specification.
static boolean	isGetterName(String methodName, boolean isBoolean) Checks whether the given method name is a valid getter name according to the JavaBeans Specification.
static boolean	isNotObjectMethod(Method method) Returns whether the given method is NOT declared in Object .
static boolean	isSetter(Method method) Checks whether the given method is a valid setter according to the JavaBeans Specification.
static boolean	isSetterName(String methodName) Checks whether the given method name is a valid setter name according to the JavaBeans Specification.
static void	setJavaFieldValue(Object object, Field field, Object value) Sets the value of a java field.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectTools

public ReflectTools()

Method Detail

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

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()).