org.springframework.util
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

Nested Class Summary

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 method fields to be operated on by a method callback.

Field Summary

static ReflectionUtils.FieldFilter

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

Constructor Summary

ReflectionUtils()

Method Summary

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 targetClass, 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 targetClass, ReflectionUtils.FieldCallback fc, 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	doWithMethods(Class targetClass, ReflectionUtils.MethodCallback mc) Perform the given callback operation on all matching methods of the given class and superclasses.
static void	doWithMethods(Class targetClass, ReflectionUtils.MethodCallback mc, ReflectionUtils.MethodFilter mf) Perform the given callback operation on all matching methods of the given class and superclasses.
static Field	findField(Class clazz, String name) Attempt to find a field on the supplied Class with the supplied name.
static Field	findField(Class clazz, String name, Class type) Attempt to find a field on the supplied Class with the supplied name and/or type.
static Method	findMethod(Class clazz, String name) Attempt to find a Method on the supplied class with the supplied name and no parameters.
static Method	findMethod(Class clazz, String name, Class[] 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 Object	getField(Field field, Object target) Get the field represented by the supplied field object on the specified target object.
static void	handleInvocationTargetException(InvocationTargetException ex) Handle the given invocation target exception.
static void	handleReflectionException(Exception ex) Handle the given reflection exception.
static Object	invokeJdbcMethod(Method method, Object target) Invoke the specified JDBC API Method against the supplied target object with no arguments.
static Object	invokeJdbcMethod(Method method, Object target, Object[] args) Invoke the specified JDBC API Method against the supplied target object with the supplied arguments.
static Object	invokeMethod(Method method, Object target) Invoke the specified Method against the supplied target object with no arguments.
static Object	invokeMethod(Method method, Object target, Object[] args) Invoke the specified Method against the supplied target object with the supplied arguments.
static boolean	isPublicStaticFinal(Field field) Determine whether the given field is a "public static final" constant.
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(Throwable ex) Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
static void	rethrowRuntimeException(Throwable ex) Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
static void	setField(Field field, Object target, 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 java.lang.Object

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

Field Detail

COPYABLE_FIELDS

public static ReflectionUtils.FieldFilter COPYABLE_FIELDS

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

Constructor Detail

ReflectionUtils

public ReflectionUtils()

Method Detail

findField

public static 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

public static Field findField(Class clazz,
                              String name,
                              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

setField

public static void setField(Field field,
                            Object target,
                            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.

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

value - the value to set; may be null

getField

public static Object getField(Field field,
                              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

Returns:

the field's current value

findMethod

public static 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 Method findMethod(Class clazz,
                                String name,
                                Class[] 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 Object invokeMethod(Method method,
                                  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(java.lang.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 Object invokeMethod(Method method,
                                  Object target,
                                  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(java.lang.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

invokeJdbcMethod

public static Object invokeJdbcMethod(Method method,
                                      Object target)
                               throws SQLException

Invoke the specified JDBC API Method against the supplied target object with no arguments.

Parameters:

method - the method to invoke

target - the target object to invoke the method on

Returns:

the invocation result, if any

Throws:

SQLException - the JDBC API SQLException to rethrow (if any)

See Also:

invokeJdbcMethod(java.lang.reflect.Method, Object, Object[])

invokeJdbcMethod

public static Object invokeJdbcMethod(Method method,
                                      Object target,
                                      Object[] args)
                               throws SQLException

Invoke the specified JDBC API Method against the supplied target object with the supplied arguments.

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

Throws:

SQLException - the JDBC API SQLException to rethrow (if any)

See Also:

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

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 the target method.

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

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 IllegalStateException else.

Parameters:

ex - the invocation target exception to handle

rethrowRuntimeException

public static void rethrowRuntimeException(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 an RuntimeException or Error if appropriate; otherwise, throws an IllegalStateException.

Parameters:

ex - the exception to rethrow

Throws:

RuntimeException - the rethrown exception

rethrowException

public static void rethrowException(Throwable ex)
                             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 IllegalStateException.

Parameters:

ex - the exception to rethrow

Throws:

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

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

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 with a JVM SecurityManager (if active).

Parameters:

field - the field to make accessible

See Also:

AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)

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 with a JVM SecurityManager (if active).

Parameters:

method - the method to make accessible

See Also:

AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)

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 with a JVM SecurityManager (if active).

Parameters:

ctor - the constructor to make accessible

See Also:

AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)

doWithMethods

public static void doWithMethods(Class targetClass,
                                 ReflectionUtils.MethodCallback mc)
                          throws IllegalArgumentException

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:

targetClass - class to start looking at

mc - the callback to invoke for each method

Throws:

IllegalArgumentException

See Also:

doWithMethods(Class, MethodCallback, MethodFilter)

doWithMethods

public static void doWithMethods(Class targetClass,
                                 ReflectionUtils.MethodCallback mc,
                                 ReflectionUtils.MethodFilter mf)
                          throws IllegalArgumentException

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 the specified ReflectionUtils.MethodFilter.

Parameters:

targetClass - class to start looking at

mc - the callback to invoke for each method

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

Throws:

IllegalArgumentException

getAllDeclaredMethods

public static Method[] getAllDeclaredMethods(Class leafClass)
                                      throws IllegalArgumentException

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

Throws:

IllegalArgumentException

doWithFields

public static void doWithFields(Class targetClass,
                                ReflectionUtils.FieldCallback fc)
                         throws IllegalArgumentException

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

Parameters:

targetClass - the target class to analyze

fc - the callback to invoke for each field

Throws:

IllegalArgumentException

doWithFields

public static void doWithFields(Class targetClass,
                                ReflectionUtils.FieldCallback fc,
                                ReflectionUtils.FieldFilter ff)
                         throws IllegalArgumentException

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

Parameters:

targetClass - 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:

IllegalArgumentException

shallowCopyFieldState

public static void shallowCopyFieldState(Object src,
                                         Object dest)
                                  throws IllegalArgumentException

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:

IllegalArgumentException - if the arguments are incompatible