com.vaadin.util

Class ReflectTools

java.lang.Object

com.vaadin.util.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.

Since:

6.2

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
static Class<?>	convertPrimitiveType(Class<?> type)
static <T> T	createInstance(Class<T> cls) Creates a instance of the given class with a no-arg constructor.
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<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 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 Method	getMethod(Class<?> listenerClass) Returns the first non-synthetic method of the specified listenerClass, which must have single method in the source-code.
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

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 IllegalAccessException,
                                     IllegalArgumentException,
                                     InvocationTargetException

Sets the value of a java field.

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

Parameters:

object - The object containing the field

field - The field we want to set the value for

value - The value to set

Throws:

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

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

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

convertPrimitiveType

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

Since:

7.4

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

Since:

8.0

createInstance

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

Creates a 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.

Parameters:

cls - the class to instantiate

Returns:

an instance of the class

Since:

8.1.1

getMethod

public static Method getMethod(Class<?> listenerClass)

Returns the first non-synthetic method of the specified listenerClass, which must have single method in the source-code. This is needed, to remove the synthetic methods added if the class is instrumented.

Parameters:

listenerClass - The Class of the listener, which has a single method in the source code

Returns:

the first non-synthetic method

Throws:

IllegalStateException - if the specified class does not have found method

Since:

8.2

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

Since:

8.16