org.jboss.weld.extensions.reflection
Class Reflections

java.lang.Object
  org.jboss.weld.extensions.reflection.Reflections

public class Reflections
extends Object

Utility class for working with JDK Reflection and also CDI's Annotated metadata.

Author:

Stuart Douglas, Pete Muir

Field Summary

static Annotation[]	EMPTY_ANNOTATION_ARRAY An empty array of type Annotation, useful converting lists to arrays.
static Object[]	EMPTY_OBJECT_ARRAY An empty array of type Object, useful for converting lists to arrays.

Method Summary

static <T> T	cast(Object obj) Perform a runtime cast.
static Class<?>	classForName(String name, ClassLoader... loaders) Loads and initializes a class for the given name.
static Constructor<?>	findDeclaredConstructor(Class<?> clazz, Class<?>... args) Search the class hierarchy for a constructor with the given arguments.
static Field	findDeclaredField(Class<?> clazz, String name) Search the class hierarchy for a field with the given name.
static Method	findDeclaredMethod(Class<?> clazz, String name, Class<?>... args) Search the class hierarchy for a method with the given name and arguments.
static Set<Constructor<?>>	getAllDeclaredConstructors(Class<?> clazz) Get all the declared constructors on the class hierarchy.
static Set<Field>	getAllDeclaredFields(Class<?> clazz) Get all the declared fields on the class hierarchy.
static Set<Method>	getAllDeclaredMethods(Class<?> clazz) Get all the declared methods on the class hierarchy.
static Set<Annotation>	getAnnotationsWithMetaAnnotation(Set<Annotation> annotations, Class<? extends Annotation> metaAnnotationType) Search for annotations with the specified meta annotation type
static <X> javax.enterprise.inject.spi.AnnotatedField<? super X>	getField(javax.enterprise.inject.spi.AnnotatedType<X> annotatedType, Field field) Search the annotatedType for the field, returning the AnnotatedField
static Object	getFieldValue(Field field, Object instance)
static <T> T	getFieldValue(Field field, Object instance, Class<T> expectedType) Get the value of the field, on the specified instance, casting the value of the field to the expected type.
static Class<?>	getMemberType(Member member) Get the type of the member
static Set<Annotation>	getQualifiers(Set<Annotation> annotations, javax.enterprise.inject.spi.BeanManager beanManager) Extract any qualifiers from the set of annotations
static <T> Class<T>	getRawType(Type type) Extract the raw type, given a type.
static <T> T	invokeMethod(Method method, Class<T> expectedReturnType, Object instance, Object... args) Invoke the method on the instance, with any arguments specified, casting the result of invoking the method to the expected return type.
static Object	invokeMethod(Method method, Object instance, Object... args) Invoke the method on the instance, with any arguments specified.
static boolean	isSerializable(Class<?> clazz) Check if a class is serializable.
static boolean	methodExists(Class<?> clazz, String name) Determine if a method exists in a specified class hierarchy
static void	setFieldValue(Field field, Object instance, Object value) Set the value of a field on the instance to the specified value.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_ANNOTATION_ARRAY

public static final Annotation[] EMPTY_ANNOTATION_ARRAY

An empty array of type Annotation, useful converting lists to arrays.

EMPTY_OBJECT_ARRAY

public static final Object[] EMPTY_OBJECT_ARRAY

An empty array of type Object, useful for converting lists to arrays.

Method Detail

cast

public static <T> T cast(Object obj)

Perform a runtime cast. Similar to Class.cast(Object), but useful when you do not have a Class object for type you wish to cast to.

Class.cast(Object) should be used if possible

Type Parameters:

T - the type to cast to

Parameters:

obj - the object to perform the cast on

Returns:

the casted object

Throws:

ClassCastException - if the type T is not a subtype of the object

See Also:

Class.cast(Object)

getAllDeclaredFields

public static Set<Field> getAllDeclaredFields(Class<?> clazz)

Get all the declared fields on the class hierarchy. This will return overridden fields.

Parameters:

clazz - The class to search

Returns:

the set of all declared fields or an empty set if there are none

findDeclaredField

public static Field findDeclaredField(Class<?> clazz,
                                      String name)

Search the class hierarchy for a field with the given name. Will return the nearest match, starting with the class specified and searching up the hierarchy.

Parameters:

clazz - The class to search

name - The name of the field to search for

Returns:

The field found, or null if no field is found

getField

public static <X> javax.enterprise.inject.spi.AnnotatedField<? super X> getField(javax.enterprise.inject.spi.AnnotatedType<X> annotatedType,
                                                                                 Field field)

Search the annotatedType for the field, returning the AnnotatedField

Parameters:

annotatedType - The annotatedType to search

field - the field to search for

Returns:

The AnnotatedField found, or null if no field is found

getAnnotationsWithMetaAnnotation

public static Set<Annotation> getAnnotationsWithMetaAnnotation(Set<Annotation> annotations,
                                                               Class<? extends Annotation> metaAnnotationType)

Search for annotations with the specified meta annotation type

Parameters:

annotations - The annotation set to search

metaAnnotationType - The type of the meta annotation to search for

Returns:

The set of annotations with the specified meta annotation, or an empty set if none are found

getQualifiers

public static Set<Annotation> getQualifiers(Set<Annotation> annotations,
                                            javax.enterprise.inject.spi.BeanManager beanManager)

Extract any qualifiers from the set of annotations

Parameters:

annotations - The set of annotations to search

beanManager - The beanManager to use to establish if an annotation is a qualifier

Returns:

The qualifiers present in the set, or an empty set if there are none

methodExists

public static boolean methodExists(Class<?> clazz,
                                   String name)

Determine if a method exists in a specified class hierarchy

Parameters:

clazz - The class to search

name - The name of the method

Returns:

true if a method is found, otherwise false

getAllDeclaredMethods

public static Set<Method> getAllDeclaredMethods(Class<?> clazz)

Get all the declared methods on the class hierarchy. This will return overridden methods.

Parameters:

clazz - The class to search

Returns:

the set of all declared methods or an empty set if there are none

findDeclaredMethod

public static Method findDeclaredMethod(Class<?> clazz,
                                        String name,
                                        Class<?>... args)

Search the class hierarchy for a method with the given name and arguments. Will return the nearest match, starting with the class specified and searching up the hierarchy.

Parameters:

clazz - The class to search

name - The name of the method to search for

args - The arguments of the method to search for

Returns:

The method found, or null if no method is found

findDeclaredConstructor

public static Constructor<?> findDeclaredConstructor(Class<?> clazz,
                                                     Class<?>... args)

Search the class hierarchy for a constructor with the given arguments. Will return the nearest match, starting with the class specified and searching up the hierarchy.

Parameters:

clazz - The class to search

args - The arguments of the constructor to search for

Returns:

The constructor found, or null if no constructor is found

getAllDeclaredConstructors

public static Set<Constructor<?>> getAllDeclaredConstructors(Class<?> clazz)

Get all the declared constructors on the class hierarchy. This will return overridden constructors.

Parameters:

clazz - The class to search

Returns:

the set of all declared constructors or an empty set if there are none

getMemberType

public static Class<?> getMemberType(Member member)

Get the type of the member

Parameters:

member - The member

Returns:

The type of the member

Throws:

UnsupportedOperationException - if the member is not a field, method, or constructor

classForName

public static Class<?> classForName(String name,
                                    ClassLoader... loaders)
                             throws ClassNotFoundException

Loads and initializes a class for the given name.

If the Thread Context Class Loader is available, it will be used, otherwise the classloader used to load Reflections will be used

It is also possible to specify additional classloaders to attempt to load the class with. If the first attempt fails, then these additional loaders are tried in order.

Parameters:

name - the name of the class to load

loaders - additional classloaders to use to attempt to load the class

Returns:

the class object

Throws:

ClassNotFoundException - if the class cannot be found

invokeMethod

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

Invoke the method on the instance, with any arguments specified.

This method wraps Method.invoke(Object, Object...), converting the checked exceptions that Method.invoke(Object, Object...) specifies to runtime exceptions.

Parameters:

method - the method to invoke

instance - the instance to invoke the method or null if the method is static

args - the arguments to the method

Returns:

the result of invoking the method, or null if the method's return type is void

Throws:

RuntimeException - if this Method object enforces Java language access control and the underlying method is inaccessible or if the underlying method throws an exception or if the initialization provoked by this method fails.

IllegalArgumentException - if the method is an instance method and the specified instance argument is not an instance of the class or interface declaring the underlying method (or of a subclass or implementor thereof); if the number of actual and formal parameters differ; if an unwrapping conversion for primitive arguments fails; or if, after possible unwrapping, a parameter value cannot be converted to the corresponding formal parameter type by a method invocation conversion.

NullPointerException - if the specified instance is null and the method is an instance method.

ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Method.invoke(Object, Object...)

invokeMethod

public static <T> T invokeMethod(Method method,
                                 Class<T> expectedReturnType,
                                 Object instance,
                                 Object... args)

Invoke the method on the instance, with any arguments specified, casting the result of invoking the method to the expected return type.

This method wraps Method.invoke(Object, Object...), converting the checked exceptions that Method.invoke(Object, Object...) specifies to runtime exceptions.

Parameters:

method - the method to invoke

instance - the instance to invoke the method

args - the arguments to the method

Returns:

the result of invoking the method, or null if the method's return type is void

Throws:

RuntimeException - if this Method object enforces Java language access control and the underlying method is inaccessible or if the underlying method throws an exception or if the initialization provoked by this method fails.

IllegalArgumentException - if the method is an instance method and the specified instance argument is not an instance of the class or interface declaring the underlying method (or of a subclass or implementor thereof); if the number of actual and formal parameters differ; if an unwrapping conversion for primitive arguments fails; or if, after possible unwrapping, a parameter value cannot be converted to the corresponding formal parameter type by a method invocation conversion.

NullPointerException - if the specified instance is null and the method is an instance method.

ClassCastException - if the result of invoking the method cannot be cast to the expectedReturnType

ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Method.invoke(Object, Object...)

setFieldValue

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

Set the value of a field on the instance to the specified value.

This method wraps Field.set(Object, Object), converting the checked exceptions that Field.set(Object, Object) specifies to runtime exceptions.

Parameters:

field - the field on which to operate, or null if the field is static

instance - the instance on which the field value should be set upon

value - the value to set the field to

Throws:

RuntimeException - if the underlying field is inaccessible.

IllegalArgumentException - if the specified instance is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.

NullPointerException - if the specified instance is null and the field is an instance field.

ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(Object, Object)

getFieldValue

public static Object getFieldValue(Field field,
                                   Object instance)

getFieldValue

public static <T> T getFieldValue(Field field,
                                  Object instance,
                                  Class<T> expectedType)

Get the value of the field, on the specified instance, casting the value of the field to the expected type.

This method wraps Field.get(Object), converting the checked exceptions that Field.get(Object) specifies to runtime exceptions.

Type Parameters:

T - the type of the field's value

Parameters:

field - the field to operate on

instance - the instance from which to retrieve the value

expectedType - the expected type of the field's value

Returns:

the value of the field

Throws:

RuntimeException - if the underlying field is inaccessible.

IllegalArgumentException - if the specified instance is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof).

NullPointerException - if the specified instance is null and the field is an instance field.

ExceptionInInitializerError - if the initialization provoked by this method fails.

getRawType

public static <T> Class<T> getRawType(Type type)

Extract the raw type, given a type.

Type Parameters:

T - the type

Parameters:

type - the type to extract the raw type from

Returns:

the raw type, or null if the raw type cannot be determined.

isSerializable

public static boolean isSerializable(Class<?> clazz)

Check if a class is serializable.

Parameters:

clazz - The class to check

Returns:

true if the class implements serializable or is a primitive