Class ReflectionUtils

java.lang.Object

org.springframework.util.ReflectionUtils

public abstract class ReflectionUtils
extends Object

Simple utility class for working with the reflection API and handling reflection exceptions.

Only intended for internal use.

Since:

1.2.2

Author:

Juergen Hoeller, Rob Harrop, Rod Johnson, Costin Leau, Sam Brannen, Chris Beams

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ReflectionUtils.FieldCallback	Callback interface invoked on each field in the hierarchy.
static interface	ReflectionUtils.FieldFilter	Callback optionally used to filter fields to be operated on by a field callback.
static interface	ReflectionUtils.MethodCallback	Action to take on each method.
static interface	ReflectionUtils.MethodFilter	Callback optionally used to filter methods to be operated on by a method callback.

Field Summary

Fields

Modifier and Type	Field	Description
static final ReflectionUtils.FieldFilter	COPYABLE_FIELDS	Pre-built FieldFilter that matches all non-static, non-final fields.
static final ReflectionUtils.MethodFilter	USER_DECLARED_METHODS	Pre-built ReflectionUtils.MethodFilter that matches all non-bridge non-synthetic methods which are not declared on java.lang.Object.

Constructor Summary

Constructors

Constructor	Description
ReflectionUtils()

Method Summary

Modifier and Type	Method	Description
static <T> Constructor<T>	accessibleConstructor(Class<T> clazz, Class<?>... parameterTypes)	Obtain an accessible constructor for the given class and parameters.
static void	clearCache()	Clear the internal method/field cache.
static boolean	declaresException(Method method, Class<?> exceptionType)	Determine whether the given method explicitly declares the given exception or one of its superclasses, which means that an exception of that type can be propagated as-is within a reflective invocation.
static void	doWithFields(Class<?> clazz, ReflectionUtils.FieldCallback fc)	Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.
static void	doWithFields(Class<?> clazz, ReflectionUtils.FieldCallback fc, @Nullable ReflectionUtils.FieldFilter ff)	Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.
static void	doWithLocalFields(Class<?> clazz, ReflectionUtils.FieldCallback fc)	Invoke the given callback on all locally declared fields in the given class.
static void	doWithLocalMethods(Class<?> clazz, ReflectionUtils.MethodCallback mc)	Perform the given callback operation on all matching methods of the given class, as locally declared or equivalent thereof (such as default methods on Java 8 based interfaces that the given class implements).
static void	doWithMethods(Class<?> clazz, ReflectionUtils.MethodCallback mc)	Perform the given callback operation on all matching methods of the given class and superclasses.
static void	doWithMethods(Class<?> clazz, ReflectionUtils.MethodCallback mc, @Nullable ReflectionUtils.MethodFilter mf)	Perform the given callback operation on all matching methods of the given class and superclasses (or given interface and super-interfaces).
static @Nullable Field	findField(Class<?> clazz, @Nullable String name, @Nullable Class<?> type)	Attempt to find a field on the supplied Class with the supplied name and/or type.
static @Nullable Field	findField(Class<?> clazz, String name)	Attempt to find a field on the supplied Class with the supplied name.
static @Nullable Field	findFieldIgnoreCase(Class<?> clazz, String name)	Attempt to find a field on the supplied Class with the supplied name.
static @Nullable Method	findMethod(Class<?> clazz, String name)	Attempt to find a Method on the supplied class with the supplied name and no parameters.
static @Nullable Method	findMethod(Class<?> clazz, String name, Class<?> @Nullable ... paramTypes)	Attempt to find a Method on the supplied class with the supplied name and parameter types.
static Method[]	getAllDeclaredMethods(Class<?> leafClass)	Get all declared methods on the leaf class and all superclasses.
static Method[]	getDeclaredMethods(Class<?> clazz)	Variant of Class.getDeclaredMethods() that uses a local cache in order to avoid new Method instances.
static @Nullable Object	getField(Field field, @Nullable Object target)	Get the field represented by the supplied field object on the specified target object.
static Method[]	getUniqueDeclaredMethods(Class<?> leafClass)	Get the unique set of declared methods on the leaf class and all superclasses.
static Method[]	getUniqueDeclaredMethods(Class<?> leafClass, @Nullable ReflectionUtils.MethodFilter mf)	Get the unique set of declared methods on the leaf class and all superclasses.
static void	handleInvocationTargetException(InvocationTargetException ex)	Handle the given invocation target exception.
static void	handleReflectionException(Exception ex)	Handle the given reflection exception.
static @Nullable Object	invokeMethod(Method method, @Nullable Object target)	Invoke the specified Method against the supplied target object with no arguments.
static @Nullable Object	invokeMethod(Method method, @Nullable Object target, @Nullable Object... args)	Invoke the specified Method against the supplied target object with the supplied arguments.
static boolean	isCglibRenamedMethod(Method renamedMethod)	Determine whether the given method is a CGLIB 'renamed' method, following the pattern "CGLIB$methodName$0".
static boolean	isEqualsMethod(@Nullable Method method)	Determine whether the given method is an "equals" method.
static boolean	isHashCodeMethod(@Nullable Method method)	Determine whether the given method is a "hashCode" method.
static boolean	isObjectMethod(@Nullable Method method)	Determine whether the given method is originally declared by Object.
static boolean	isPublicStaticFinal(Field field)	Determine whether the given field is a "public static final" constant.
static boolean	isToStringMethod(@Nullable Method method)	Determine whether the given method is a "toString" method.
static void	makeAccessible(Constructor<?> ctor)	Make the given constructor accessible, explicitly setting it accessible if necessary.
static void	makeAccessible(Field field)	Make the given field accessible, explicitly setting it accessible if necessary.
static void	makeAccessible(Method method)	Make the given method accessible, explicitly setting it accessible if necessary.
static void	rethrowException(@Nullable Throwable throwable)	Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
static void	rethrowRuntimeException(@Nullable Throwable ex)	Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
static void	setField(Field field, @Nullable Object target, @Nullable Object value)	Set the field represented by the supplied field object on the specified target object to the specified value.
static void	shallowCopyFieldState(Object src, Object dest)	Given the source object and the destination, which must be the same class or a subclass, copy all fields, including inherited fields.

Methods inherited from class Object

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

Field Details

USER_DECLARED_METHODS

public static final ReflectionUtils.MethodFilter USER_DECLARED_METHODS

Pre-built ReflectionUtils.MethodFilter that matches all non-bridge non-synthetic methods which are not declared on java.lang.Object.

Since:

3.0.5

COPYABLE_FIELDS

public static final ReflectionUtils.FieldFilter COPYABLE_FIELDS

Pre-built FieldFilter that matches all non-static, non-final fields.

Constructor Details

ReflectionUtils

public ReflectionUtils()

Method Details

handleReflectionException

public static void handleReflectionException(Exception ex)

Handle the given reflection exception.

Should only be called if no checked exception is expected to be thrown by a target method, or if an error occurs while accessing a method or field.

Throws the underlying RuntimeException or Error in case of an InvocationTargetException with such a root cause. Throws an IllegalStateException with an appropriate message or UndeclaredThrowableException otherwise.

Parameters:

ex - the reflection exception to handle

handleInvocationTargetException

public static void handleInvocationTargetException(InvocationTargetException ex)

Handle the given invocation target exception. Should only be called if no checked exception is expected to be thrown by the target method.

Throws the underlying RuntimeException or Error in case of such a root cause. Throws an UndeclaredThrowableException otherwise.

Parameters:

ex - the invocation target exception to handle

rethrowRuntimeException

@Contract("_ -> fail")
public static void rethrowRuntimeException(@Nullable Throwable ex)

Rethrow the given exception, which is presumably the target exception of an InvocationTargetException. Should only be called if no checked exception is expected to be thrown by the target method.

Rethrows the underlying exception cast to a RuntimeException or Error if appropriate; otherwise, throws an UndeclaredThrowableException.

Parameters:

ex - the exception to rethrow

Throws:

RuntimeException - the rethrown exception

rethrowException

@Contract("_ -> fail")
public static void rethrowException(@Nullable Throwable throwable)
                             throws Exception

Rethrow the given exception, which is presumably the target exception of an InvocationTargetException. Should only be called if no checked exception is expected to be thrown by the target method.

Rethrows the underlying exception cast to an Exception or Error if appropriate; otherwise, throws an UndeclaredThrowableException.

Parameters:

throwable - the exception to rethrow

Throws:

Exception - the rethrown exception (in case of a checked exception)

accessibleConstructor

public static <T> Constructor<T> accessibleConstructor(Class<T> clazz,
 Class<?>... parameterTypes)
                                                throws NoSuchMethodException

Obtain an accessible constructor for the given class and parameters.

Parameters:

clazz - the clazz to check

parameterTypes - the parameter types of the desired constructor

Returns:

the constructor reference

Throws:

NoSuchMethodException - if no such constructor exists

Since:

5.0

makeAccessible

public static void makeAccessible(Constructor<?> ctor)

Make the given constructor accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts.

Parameters:

ctor - the constructor to make accessible

See Also:

• Constructor.setAccessible(boolean)

findMethod

public static @Nullable Method findMethod(Class<?> clazz,
 String name)

Attempt to find a Method on the supplied class with the supplied name and no parameters. Searches all superclasses up to Object.

Returns null if no Method can be found.

Parameters:

clazz - the class to introspect

name - the name of the method

Returns:

the Method object, or null if none found

findMethod

public static @Nullable Method findMethod(Class<?> clazz,
 String name,
 Class<?> @Nullable ... paramTypes)

Attempt to find a Method on the supplied class with the supplied name and parameter types. Searches all superclasses up to Object.

Returns null if no Method can be found.

Parameters:

clazz - the class to introspect

name - the name of the method

paramTypes - the parameter types of the method (may be null to indicate any signature)

Returns:

the Method object, or null if none found

invokeMethod

public static @Nullable Object invokeMethod(Method method,
 @Nullable Object target)

Invoke the specified Method against the supplied target object with no arguments. The target object can be null when invoking a static Method.

Thrown exceptions are handled via a call to handleReflectionException(Exception).

Parameters:

method - the method to invoke

target - the target object to invoke the method on

Returns:

the invocation result, if any

See Also:

• invokeMethod(java.lang.reflect.Method, Object, Object[])

invokeMethod

public static @Nullable Object invokeMethod(Method method,
 @Nullable Object target,
 @Nullable Object... args)

Invoke the specified Method against the supplied target object with the supplied arguments. The target object can be null when invoking a static Method.

Thrown exceptions are handled via a call to handleReflectionException(Exception).

Parameters:

method - the method to invoke

target - the target object to invoke the method on

args - the invocation arguments (may be null)

Returns:

the invocation result, if any

declaresException

public static boolean declaresException(Method method,
 Class<?> exceptionType)

Determine whether the given method explicitly declares the given exception or one of its superclasses, which means that an exception of that type can be propagated as-is within a reflective invocation.

Parameters:

method - the declaring method

exceptionType - the exception to throw

Returns:

true if the exception can be thrown as-is; false if it needs to be wrapped

doWithLocalMethods

public static void doWithLocalMethods(Class<?> clazz,
 ReflectionUtils.MethodCallback mc)

Perform the given callback operation on all matching methods of the given class, as locally declared or equivalent thereof (such as default methods on Java 8 based interfaces that the given class implements).

Parameters:

clazz - the class to introspect

mc - the callback to invoke for each method

Throws:

IllegalStateException - if introspection fails

Since:

4.2

See Also:

• doWithMethods(Class, ReflectionUtils.MethodCallback)

doWithMethods

public static void doWithMethods(Class<?> clazz,
 ReflectionUtils.MethodCallback mc)

Perform the given callback operation on all matching methods of the given class and superclasses.

The same named method occurring on subclass and superclass will appear twice, unless excluded by a ReflectionUtils.MethodFilter.

Parameters:

clazz - the class to introspect

mc - the callback to invoke for each method

Throws:

IllegalStateException - if introspection fails

See Also:

• doWithMethods(Class, MethodCallback, MethodFilter)

doWithMethods

public static void doWithMethods(Class<?> clazz,
 ReflectionUtils.MethodCallback mc,
 @Nullable ReflectionUtils.MethodFilter mf)

Perform the given callback operation on all matching methods of the given class and superclasses (or given interface and super-interfaces).

The same named method occurring on subclass and superclass will appear twice, unless excluded by the specified ReflectionUtils.MethodFilter.

Parameters:

clazz - the class to introspect

mc - the callback to invoke for each method

mf - the filter that determines the methods to apply the callback to

Throws:

IllegalStateException - if introspection fails

getAllDeclaredMethods

public static Method[] getAllDeclaredMethods(Class<?> leafClass)

Get all declared methods on the leaf class and all superclasses. Leaf class methods are included first.

Parameters:

leafClass - the class to introspect

Throws:

IllegalStateException - if introspection fails

getUniqueDeclaredMethods

public static Method[] getUniqueDeclaredMethods(Class<?> leafClass)

Get the unique set of declared methods on the leaf class and all superclasses. Leaf class methods are included first and while traversing the superclass hierarchy any methods found with signatures matching a method already included are filtered out.

Parameters:

leafClass - the class to introspect

Throws:

IllegalStateException - if introspection fails

getUniqueDeclaredMethods

public static Method[] getUniqueDeclaredMethods(Class<?> leafClass,
 @Nullable ReflectionUtils.MethodFilter mf)

Get the unique set of declared methods on the leaf class and all superclasses. Leaf class methods are included first and while traversing the superclass hierarchy any methods found with signatures matching a method already included are filtered out.

Parameters:

leafClass - the class to introspect

mf - the filter that determines the methods to take into account

Throws:

IllegalStateException - if introspection fails

Since:

5.2

getDeclaredMethods

public static Method[] getDeclaredMethods(Class<?> clazz)

Variant of Class.getDeclaredMethods() that uses a local cache in order to avoid new Method instances. In addition, it also includes Java 8 default methods from locally implemented interfaces, since those are effectively to be treated just like declared methods.

Parameters:

clazz - the class to introspect

Returns:

the cached array of methods

Throws:

IllegalStateException - if introspection fails

Since:

5.2

See Also:

• Class.getDeclaredMethods()

isEqualsMethod

@Contract("null -> false")
public static boolean isEqualsMethod(@Nullable Method method)

Determine whether the given method is an "equals" method.

See Also:

• Object.equals(Object)

isHashCodeMethod

@Contract("null -> false")
public static boolean isHashCodeMethod(@Nullable Method method)

Determine whether the given method is a "hashCode" method.

See Also:

• Object.hashCode()

isToStringMethod

@Contract("null -> false")
public static boolean isToStringMethod(@Nullable Method method)

Determine whether the given method is a "toString" method.

See Also:

• Object.toString()

isObjectMethod

@Contract("null -> false")
public static boolean isObjectMethod(@Nullable Method method)

Determine whether the given method is originally declared by Object.

isCglibRenamedMethod

public static boolean isCglibRenamedMethod(Method renamedMethod)

Determine whether the given method is a CGLIB 'renamed' method, following the pattern "CGLIB$methodName$0".

Parameters:

renamedMethod - the method to check

makeAccessible

public static void makeAccessible(Method method)

Make the given method accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts.

Parameters:

method - the method to make accessible

See Also:

• Method.setAccessible(boolean)

findField

public static @Nullable Field findField(Class<?> clazz,
 String name)

Attempt to find a field on the supplied Class with the supplied name. Searches all superclasses up to Object.

Parameters:

clazz - the class to introspect

name - the name of the field

Returns:

the corresponding Field object, or null if not found

findField

@Contract("_, null, null -> fail")
public static @Nullable Field findField(Class<?> clazz,
 @Nullable String name,
 @Nullable Class<?> type)

Attempt to find a field on the supplied Class with the supplied name and/or type. Searches all superclasses up to Object.

Parameters:

clazz - the class to introspect

name - the name of the field (may be null if type is specified)

type - the type of the field (may be null if name is specified)

Returns:

the corresponding Field object, or null if not found

findFieldIgnoreCase

public static @Nullable Field findFieldIgnoreCase(Class<?> clazz,
 String name)

Attempt to find a field on the supplied Class with the supplied name. Searches all superclasses up to Object.

Parameters:

clazz - the class to introspect

name - the name of the field (with upper/lower case to be ignored)

Returns:

the corresponding Field object, or null if not found

Since:

6.1

setField

public static void setField(Field field,
 @Nullable Object target,
 @Nullable Object value)

Set the field represented by the supplied field object on the specified target object to the specified value.

In accordance with Field.set(Object, Object) semantics, the new value is automatically unwrapped if the underlying field has a primitive type.

This method does not support setting static final fields.

Thrown exceptions are handled via a call to handleReflectionException(Exception).

Parameters:

field - the field to set

target - the target object on which to set the field (or null for a static field)

value - the value to set (may be null)

getField

public static @Nullable Object getField(Field field,
 @Nullable Object target)

Get the field represented by the supplied field object on the specified target object. In accordance with Field.get(Object) semantics, the returned value is automatically wrapped if the underlying field has a primitive type.

Thrown exceptions are handled via a call to handleReflectionException(Exception).

Parameters:

field - the field to get

target - the target object from which to get the field (or null for a static field)

Returns:

the field's current value

doWithLocalFields

public static void doWithLocalFields(Class<?> clazz,
 ReflectionUtils.FieldCallback fc)

Invoke the given callback on all locally declared fields in the given class.

Parameters:

clazz - the target class to analyze

fc - the callback to invoke for each field

Throws:

IllegalStateException - if introspection fails

Since:

4.2

See Also:

• doWithFields(Class, ReflectionUtils.FieldCallback)

doWithFields

public static void doWithFields(Class<?> clazz,
 ReflectionUtils.FieldCallback fc)

Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.

Parameters:

clazz - the target class to analyze

fc - the callback to invoke for each field

Throws:

IllegalStateException - if introspection fails

doWithFields

public static void doWithFields(Class<?> clazz,
 ReflectionUtils.FieldCallback fc,
 @Nullable ReflectionUtils.FieldFilter ff)

Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.

Parameters:

clazz - the target class to analyze

fc - the callback to invoke for each field

ff - the filter that determines the fields to apply the callback to

Throws:

IllegalStateException - if introspection fails

shallowCopyFieldState

public static void shallowCopyFieldState(Object src,
 Object dest)

Given the source object and the destination, which must be the same class or a subclass, copy all fields, including inherited fields. Designed to work on objects with public no-arg constructors.

Throws:

IllegalStateException - if introspection fails

isPublicStaticFinal

public static boolean isPublicStaticFinal(Field field)

Determine whether the given field is a "public static final" constant.

Parameters:

field - the field to check

makeAccessible

public static void makeAccessible(Field field)

Make the given field accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts.

Parameters:

field - the field to make accessible

See Also:

• Field.setAccessible(boolean)

clearCache

public static void clearCache()

Clear the internal method/field cache.

Since:

4.2.4