Package io.vertigo.core.util

Class ClassUtil

java.lang.Object

io.vertigo.core.util.ClassUtil

public final class ClassUtil
extends Object

The ClassUtil class provides methods to determine the structure of a class or to create instances.

Author:

pchretien

Method Summary

Modifier and Type	Method	Description
static Class<?>	classForName(String javaClassName)	Retrieves an untyped class from its name.
static <J> Class<? extends J>	classForName(String javaClassName, Class<J> type)	Retrieves a typed class from its name.
static <J> Constructor<J>	findConstructor(Class<J> clazz, Class<?>[] parameterTypes)	Retrieves the constructor corresponding to the given signature.
static Method	findMethod(Class<?> clazz, String methodName, Class<?>... parameterTypes)	Retrieves the method corresponding to the name and signature among the passed methods.
static Object	get(Object instance, Field field)	Dynamic retrieval of a field's value.
static Collection<Field>	getAllFields(Class<?> clazz)	Returns all declared fields (including parent fields) for a given class.
static Collection<Field>	getAllFields(Class<?> clazz, Class<? extends Annotation> annotation)	Returns all declared fields (including parent fields) annotated for a given class.
static Set<Class<?>>	getAllInterfaces(Class<?> clazz)	Returns all interfaces (including those of the parents) for a given class.
static Collection<Method>	getAllMethods(Class<?> clazz)	Returns all declared methods for a given class (including parent methods).
static Collection<Method>	getAllMethods(Class<?> clazz, Class<? extends Annotation> annotation)	Returns all declared methods annotated by the given annotation.
static Class<?>	getGeneric(Constructor<?> constructor, int i)	Retrieves the generic type of a parameterized field.
static Class<?>	getGeneric(Field field)	Retrieves the generic type of a parameterized field.
static Class<?>	getGeneric(Method method, int i)	Retrieves the generic type of a parameterized method.
static Object	invoke(Object instance, Method method, Object... args)	Dynamic invocation of a method on a specific instance.
static <J> J	newInstance(Class<J> clazz)	Creates a new typed instance via a class (empty constructor).
static <J> J	newInstance(Constructor<J> constructor, Object[] args)	Creates a new typed instance via a constructor and its arguments.
static Object	newInstance(String javaClassName)	Creates a new untyped instance via class name (empty constructor).
static <J> J	newInstance(String javaClassName, Class<J> type)	Creates a new typed instance via class name (empty constructor).
static void	set(Object instance, Field field, Object value)	Dynamic assignment of a field's value (even private).

Methods inherited from class java.lang.Object

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

Method Details

newInstance

public static Object newInstance(String javaClassName)

Creates a new untyped instance via class name (empty constructor). Please favor methods returning a typed instance as soon as the type is known.

Parameters:

javaClassName - Class name

Returns:

New instance

newInstance

public static <J> J newInstance(String javaClassName,
 Class<J> type)

Creates a new typed instance via class name (empty constructor).

Type Parameters:

J - Type of the returned instance

Parameters:

javaClassName - Class name

type - Returned type

Returns:

New instance

newInstance

public static <J> J newInstance(Class<J> clazz)

Creates a new typed instance via a class (empty constructor).

Type Parameters:

J - Type of the returned instance

Parameters:

clazz - Class

Returns:

New instance

newInstance

public static <J> J newInstance(Constructor<J> constructor,
 Object[] args)

Creates a new typed instance via a constructor and its arguments.

Type Parameters:

J - Type of the returned instance

Parameters:

constructor - Constructor

args - Construction arguments

Returns:

New instance

findConstructor

public static <J> Constructor<J> findConstructor(Class<J> clazz,
 Class<?>[] parameterTypes)

Retrieves the constructor corresponding to the given signature.

Type Parameters:

J - Class type

Parameters:

clazz - Class to search for the constructor

parameterTypes - Signature of the searched constructor

Returns:

Searched constructor

classForName

public static Class<?> classForName(String javaClassName)

Retrieves an untyped class from its name.

Parameters:

javaClassName - Class name

Returns:

Java class

classForName

public static <J> Class<? extends J> classForName(String javaClassName,
 Class<J> type)

Retrieves a typed class from its name.

Type Parameters:

J - Type of the returned instance

Parameters:

javaClassName - Class name

type - Type.

Returns:

Java class

invoke

public static Object invoke(Object instance,
 Method method,
 Object... args)

Dynamic invocation of a method on a specific instance.

Parameters:

instance - Object

method - method which is invoked

args - Args

Returns:

value provided as the result by the method

set

public static void set(Object instance,
 Field field,
 Object value)

Dynamic assignment of a field's value (even private).

Parameters:

instance - Object on which the method is invoked

field - Field concerned

value - New value

get

public static Object get(Object instance,
 Field field)

Dynamic retrieval of a field's value.

Parameters:

instance - Object on which the method is invoked

field - Concerned field

Returns:

Value

findMethod

public static Method findMethod(Class<?> clazz,
 String methodName,
 Class<?>... parameterTypes)

Retrieves the method corresponding to the name and signature among the passed methods.

Parameters:

clazz - Class on which we are searching for methods

methodName - Name of the searched method

parameterTypes - Signature of the searched method

Returns:

Searched method

getAllFields

public static Collection<Field> getAllFields(Class<?> clazz,
 Class<? extends Annotation> annotation)

Returns all declared fields (including parent fields) annotated for a given class.

Parameters:

clazz - Class

annotation - Expected annotation

Returns:

All declared fields (including parent fields)

getAllMethods

public static Collection<Method> getAllMethods(Class<?> clazz,
 Class<? extends Annotation> annotation)

Returns all declared methods annotated by the given annotation.

Parameters:

clazz - Class

annotation - Expected annotation

Returns:

All declared fields (including parent fields)

getAllFields

public static Collection<Field> getAllFields(Class<?> clazz)

Returns all declared fields (including parent fields) for a given class.

Parameters:

clazz - Class

Returns:

All declared fields (including parent fields)

getAllMethods

public static Collection<Method> getAllMethods(Class<?> clazz)

Returns all declared methods for a given class (including parent methods).

Parameters:

clazz - Class

Returns:

All declared methods (including parent methods)

getAllInterfaces

public static Set<Class<?>> getAllInterfaces(Class<?> clazz)

Returns all interfaces (including those of the parents) for a given class.

Parameters:

clazz - Class

Returns:

All implemented interfaces

getGeneric

public static Class<?> getGeneric(Constructor<?> constructor,
 int i)

Retrieves the generic type of a parameterized field. It is expected that there is ONE and only ONE declared generic. Example: List => Car Option => Car

Parameters:

constructor - Constructor

i - Index of the parameter in the component

Returns:

Class of the generic type

getGeneric

public static Class<?> getGeneric(Method method,
 int i)

Retrieves the generic type of a parameterized method. It is expected that there is ONE and only ONE declared generic. Example: List => Car Option => Car

Parameters:

method - Method

i - Index of the parameter in the component

Returns:

Class of the generic type

getGeneric

public static Class<?> getGeneric(Field field)

Retrieves the generic type of a parameterized field. It is expected that there is ONE and only ONE declared generic. Example: List => Car Option => Car

Parameters:

field - Field

Returns:

Class of the generic type