spring ReflectionUtils 源码
spring ReflectionUtils 代码
文件路径：/spring-core/src/main/java/org/springframework/util/ReflectionUtils.java
/*
* Copyright 2002-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.UndeclaredThrowableException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import org.springframework.lang.Nullable;
/**
* Simple utility class for working with the reflection API and handling
* reflection exceptions.
*
* <p>Only intended for internal use.
*
* @author Juergen Hoeller
* @author Rob Harrop
* @author Rod Johnson
* @author Costin Leau
* @author Sam Brannen
* @author Chris Beams
* @since 1.2.2
*/
public abstract class ReflectionUtils {
/**
* Pre-built {@link MethodFilter} that matches all non-bridge non-synthetic methods
* which are not declared on {@code java.lang.Object}.
* @since 3.0.5
*/
public static final MethodFilter USER_DECLARED_METHODS =
(method -> !method.isBridge() && !method.isSynthetic() && (method.getDeclaringClass() != Object.class));
/**
* Pre-built FieldFilter that matches all non-static, non-final fields.
*/
public static final FieldFilter COPYABLE_FIELDS =
(field -> !(Modifier.isStatic(field.getModifiers()) || Modifier.isFinal(field.getModifiers())));
/**
* Naming prefix for CGLIB-renamed methods.
* @see #isCglibRenamedMethod
*/
private static final String CGLIB_RENAMED_METHOD_PREFIX = "CGLIB$";
private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
private static final Method[] EMPTY_METHOD_ARRAY = new Method[0];
private static final Field[] EMPTY_FIELD_ARRAY = new Field[0];
private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
/**
* Cache for {@link Class#getDeclaredMethods()} plus equivalent default methods
* from Java 8 based interfaces, allowing for fast iteration.
*/
private static final Map<Class<?>, Method[]> declaredMethodsCache = new ConcurrentReferenceHashMap<>(256);
/**
* Cache for {@link Class#getDeclaredFields()}, allowing for fast iteration.
*/
private static final Map<Class<?>, Field[]> declaredFieldsCache = new ConcurrentReferenceHashMap<>(256);
// Exception handling
/**
* Handle the given reflection exception.
* <p>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.
* <p>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.
* @param ex the reflection exception to handle
*/
public static void handleReflectionException(Exception ex) {
if (ex instanceof NoSuchMethodException) {
throw new IllegalStateException("Method not found: " + ex.getMessage());
}
if (ex instanceof IllegalAccessException) {
throw new IllegalStateException("Could not access method or field: " + ex.getMessage());
}
if (ex instanceof InvocationTargetException invocationTargetException) {
handleInvocationTargetException(invocationTargetException);
}
if (ex instanceof RuntimeException runtimeException) {
throw runtimeException;
}
throw new UndeclaredThrowableException(ex);
}
/**
* Handle the given invocation target exception. Should only be called if no
* checked exception is expected to be thrown by the target method.
* <p>Throws the underlying RuntimeException or Error in case of such a root
* cause. Throws an UndeclaredThrowableException otherwise.
* @param ex the invocation target exception to handle
*/
public static void handleInvocationTargetException(InvocationTargetException ex) {
rethrowRuntimeException(ex.getTargetException());
}
/**
* Rethrow the given {@link Throwable exception}, which is presumably the
* <em>target exception</em> of an {@link InvocationTargetException}.
* Should only be called if no checked exception is expected to be thrown
* by the target method.
* <p>Rethrows the underlying exception cast to a {@link RuntimeException} or
* {@link Error} if appropriate; otherwise, throws an
* {@link UndeclaredThrowableException}.
* @param ex the exception to rethrow
* @throws RuntimeException the rethrown exception
*/
public static void rethrowRuntimeException(Throwable ex) {
if (ex instanceof RuntimeException runtimeException) {
throw runtimeException;
}
if (ex instanceof Error error) {
throw error;
}
throw new UndeclaredThrowableException(ex);
}
/**
* Rethrow the given {@link Throwable exception}, which is presumably the
* <em>target exception</em> of an {@link InvocationTargetException}.
* Should only be called if no checked exception is expected to be thrown
* by the target method.
* <p>Rethrows the underlying exception cast to an {@link Exception} or
* {@link Error} if appropriate; otherwise, throws an
* {@link UndeclaredThrowableException}.
* @param throwable the exception to rethrow
* @throws Exception the rethrown exception (in case of a checked exception)
*/
public static void rethrowException(Throwable throwable) throws Exception {
if (throwable instanceof Exception exception) {
throw exception;
}
if (throwable instanceof Error error) {
throw error;
}
throw new UndeclaredThrowableException(throwable);
}
// Constructor handling
/**
* Obtain an accessible constructor for the given class and parameters.
* @param clazz the clazz to check
* @param parameterTypes the parameter types of the desired constructor
* @return the constructor reference
* @throws NoSuchMethodException if no such constructor exists
* @since 5.0
*/
public static <T> Constructor<T> accessibleConstructor(Class<T> clazz, Class<?>... parameterTypes)
throws NoSuchMethodException {
Constructor<T> ctor = clazz.getDeclaredConstructor(parameterTypes);
makeAccessible(ctor);
return ctor;
}
/**
* Make the given constructor accessible, explicitly setting it accessible
* if necessary. The {@code setAccessible(true)} method is only called
* when actually necessary, to avoid unnecessary conflicts.
* @param ctor the constructor to make accessible
* @see java.lang.reflect.Constructor#setAccessible
*/
@SuppressWarnings("deprecation")
public static void makeAccessible(Constructor<?> ctor) {
if ((!Modifier.isPublic(ctor.getModifiers()) ||
!Modifier.isPublic(ctor.getDeclaringClass().getModifiers())) && !ctor.isAccessible()) {
ctor.setAccessible(true);
}
}
// Method handling
/**
* Attempt to find a {@link Method} on the supplied class with the supplied name
* and no parameters. Searches all superclasses up to {@code Object}.
* <p>Returns {@code null} if no {@link Method} can be found.
* @param clazz the class to introspect
* @param name the name of the method
* @return the Method object, or {@code null} if none found
*/
@Nullable
public static Method findMethod(Class<?> clazz, String name) {
return findMethod(clazz, name, EMPTY_CLASS_ARRAY);
}
/**
* Attempt to find a {@link Method} on the supplied class with the supplied name
* and parameter types. Searches all superclasses up to {@code Object}.
* <p>Returns {@code null} if no {@link Method} can be found.
* @param clazz the class to introspect
* @param name the name of the method
* @param paramTypes the parameter types of the method
* (may be {@code null} to indicate any signature)
* @return the Method object, or {@code null} if none found
*/
@Nullable
public static Method findMethod(Class<?> clazz, String name, @Nullable Class<?>... paramTypes) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(name, "Method name must not be null");
Class<?> searchType = clazz;
while (searchType != null) {
Method[] methods = (searchType.isInterface() ? searchType.getMethods() :
getDeclaredMethods(searchType, false));
for (Method method : methods) {
if (name.equals(method.getName()) && (paramTypes == null || hasSameParams(method, paramTypes))) {
return method;
}
}
searchType = searchType.getSuperclass();
}
return null;
}
private static boolean hasSameParams(Method method, Class<?>[] paramTypes) {
return (paramTypes.length == method.getParameterCount() &&
Arrays.equals(paramTypes, method.getParameterTypes()));
}
/**
* Invoke the specified {@link Method} against the supplied target object with no arguments.
* The target object can be {@code null} when invoking a static {@link Method}.
* <p>Thrown exceptions are handled via a call to {@link #handleReflectionException}.
* @param method the method to invoke
* @param target the target object to invoke the method on
* @return the invocation result, if any
* @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
*/
@Nullable
public static Object invokeMethod(Method method, @Nullable Object target) {
return invokeMethod(method, target, EMPTY_OBJECT_ARRAY);
}
/**
* Invoke the specified {@link Method} against the supplied target object with the
* supplied arguments. The target object can be {@code null} when invoking a
* static {@link Method}.
* <p>Thrown exceptions are handled via a call to {@link #handleReflectionException}.
* @param method the method to invoke
* @param target the target object to invoke the method on
* @param args the invocation arguments (may be {@code null})
* @return the invocation result, if any
*/
@Nullable
public static Object invokeMethod(Method method, @Nullable Object target, @Nullable Object... args) {
try {
return method.invoke(target, args);
}
catch (Exception ex) {
handleReflectionException(ex);
}
throw new IllegalStateException("Should never get here");
}
/**
* 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.
* @param method the declaring method
* @param exceptionType the exception to throw
* @return {@code true} if the exception can be thrown as-is;
* {@code false} if it needs to be wrapped
*/
public static boolean declaresException(Method method, Class<?> exceptionType) {
Assert.notNull(method, "Method must not be null");
Class<?>[] declaredExceptions = method.getExceptionTypes();
for (Class<?> declaredException : declaredExceptions) {
if (declaredException.isAssignableFrom(exceptionType)) {
return true;
}
}
return false;
}
/**
* 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).
* @param clazz the class to introspect
* @param mc the callback to invoke for each method
* @throws IllegalStateException if introspection fails
* @since 4.2
* @see #doWithMethods
*/
public static void doWithLocalMethods(Class<?> clazz, MethodCallback mc) {
Method[] methods = getDeclaredMethods(clazz, false);
for (Method method : methods) {
try {
mc.doWith(method);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException("Not allowed to access method '" + method.getName() + "': " + ex);
}
}
}
/**
* Perform the given callback operation on all matching methods of the given
* class and superclasses.
* <p>The same named method occurring on subclass and superclass will appear
* twice, unless excluded by a {@link MethodFilter}.
* @param clazz the class to introspect
* @param mc the callback to invoke for each method
* @throws IllegalStateException if introspection fails
* @see #doWithMethods(Class, MethodCallback, MethodFilter)
*/
public static void doWithMethods(Class<?> clazz, MethodCallback mc) {
doWithMethods(clazz, mc, null);
}
/**
* Perform the given callback operation on all matching methods of the given
* class and superclasses (or given interface and super-interfaces).
* <p>The same named method occurring on subclass and superclass will appear
* twice, unless excluded by the specified {@link MethodFilter}.
* @param clazz the class to introspect
* @param mc the callback to invoke for each method
* @param mf the filter that determines the methods to apply the callback to
* @throws IllegalStateException if introspection fails
*/
public static void doWithMethods(Class<?> clazz, MethodCallback mc, @Nullable MethodFilter mf) {
if (mf == USER_DECLARED_METHODS && clazz == Object.class) {
// nothing to introspect
return;
}
Method[] methods = getDeclaredMethods(clazz, false);
for (Method method : methods) {
if (mf != null && !mf.matches(method)) {
continue;
}
try {
mc.doWith(method);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException("Not allowed to access method '" + method.getName() + "': " + ex);
}
}
// Keep backing up the inheritance hierarchy.
if (clazz.getSuperclass() != null && (mf != USER_DECLARED_METHODS || clazz.getSuperclass() != Object.class)) {
doWithMethods(clazz.getSuperclass(), mc, mf);
}
else if (clazz.isInterface()) {
for (Class<?> superIfc : clazz.getInterfaces()) {
doWithMethods(superIfc, mc, mf);
}
}
}
/**
* Get all declared methods on the leaf class and all superclasses.
* Leaf class methods are included first.
* @param leafClass the class to introspect
* @throws IllegalStateException if introspection fails
*/
public static Method[] getAllDeclaredMethods(Class<?> leafClass) {
final List<Method> methods = new ArrayList<>(20);
doWithMethods(leafClass, methods::add);
return methods.toArray(EMPTY_METHOD_ARRAY);
}
/**
* 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.
* @param leafClass the class to introspect
* @throws IllegalStateException if introspection fails
*/
public static Method[] getUniqueDeclaredMethods(Class<?> leafClass) {
return getUniqueDeclaredMethods(leafClass, null);
}
/**
* 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.
* @param leafClass the class to introspect
* @param mf the filter that determines the methods to take into account
* @throws IllegalStateException if introspection fails
* @since 5.2
*/
public static Method[] getUniqueDeclaredMethods(Class<?> leafClass, @Nullable MethodFilter mf) {
final List<Method> methods = new ArrayList<>(20);
doWithMethods(leafClass, method -> {
boolean knownSignature = false;
Method methodBeingOverriddenWithCovariantReturnType = null;
for (Method existingMethod : methods) {
if (method.getName().equals(existingMethod.getName()) &&
method.getParameterCount() == existingMethod.getParameterCount() &&
Arrays.equals(method.getParameterTypes(), existingMethod.getParameterTypes())) {
// Is this a covariant return type situation?
if (existingMethod.getReturnType() != method.getReturnType() &&
existingMethod.getReturnType().isAssignableFrom(method.getReturnType())) {
methodBeingOverriddenWithCovariantReturnType = existingMethod;
}
else {
knownSignature = true;
}
break;
}
}
if (methodBeingOverriddenWithCovariantReturnType != null) {
methods.remove(methodBeingOverriddenWithCovariantReturnType);
}
if (!knownSignature && !isCglibRenamedMethod(method)) {
methods.add(method);
}
}, mf);
return methods.toArray(EMPTY_METHOD_ARRAY);
}
/**
* Variant of {@link 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.
* @param clazz the class to introspect
* @return the cached array of methods
* @throws IllegalStateException if introspection fails
* @since 5.2
* @see Class#getDeclaredMethods()
*/
public static Method[] getDeclaredMethods(Class<?> clazz) {
return getDeclaredMethods(clazz, true);
}
private static Method[] getDeclaredMethods(Class<?> clazz, boolean defensive) {
Assert.notNull(clazz, "Class must not be null");
Method[] result = declaredMethodsCache.get(clazz);
if (result == null) {
try {
Method[] declaredMethods = clazz.getDeclaredMethods();
List<Method> defaultMethods = findConcreteMethodsOnInterfaces(clazz);
if (defaultMethods != null) {
result = new Method[declaredMethods.length + defaultMethods.size()];
System.arraycopy(declaredMethods, 0, result, 0, declaredMethods.length);
int index = declaredMethods.length;
for (Method defaultMethod : defaultMethods) {
result[index] = defaultMethod;
index++;
}
}
else {
result = declaredMethods;
}
declaredMethodsCache.put(clazz, (result.length == 0 ? EMPTY_METHOD_ARRAY : result));
}
catch (Throwable ex) {
throw new IllegalStateException("Failed to introspect Class [" + clazz.getName() +
"] from ClassLoader [" + clazz.getClassLoader() + "]", ex);
}
}
return (result.length == 0 || !defensive) ? result : result.clone();
}
@Nullable
private static List<Method> findConcreteMethodsOnInterfaces(Class<?> clazz) {
List<Method> result = null;
for (Class<?> ifc : clazz.getInterfaces()) {
for (Method ifcMethod : ifc.getMethods()) {
if (!Modifier.isAbstract(ifcMethod.getModifiers())) {
if (result == null) {
result = new ArrayList<>();
}
result.add(ifcMethod);
}
}
}
return result;
}
/**
* Determine whether the given method is an "equals" method.
* @see java.lang.Object#equals(Object)
*/
public static boolean isEqualsMethod(@Nullable Method method) {
if (method == null) {
return false;
}
if (method.getParameterCount() != 1) {
return false;
}
if (!method.getName().equals("equals")) {
return false;
}
return method.getParameterTypes()[0] == Object.class;
}
/**
* Determine whether the given method is a "hashCode" method.
* @see java.lang.Object#hashCode()
*/
public static boolean isHashCodeMethod(@Nullable Method method) {
return method != null && method.getParameterCount() == 0 && method.getName().equals("hashCode");
}
/**
* Determine whether the given method is a "toString" method.
* @see java.lang.Object#toString()
*/
public static boolean isToStringMethod(@Nullable Method method) {
return (method != null && method.getParameterCount() == 0 && method.getName().equals("toString"));
}
/**
* Determine whether the given method is originally declared by {@link java.lang.Object}.
*/
public static boolean isObjectMethod(@Nullable Method method) {
return (method != null && (method.getDeclaringClass() == Object.class ||
isEqualsMethod(method) || isHashCodeMethod(method) || isToStringMethod(method)));
}
/**
* Determine whether the given method is a CGLIB 'renamed' method,
* following the pattern "CGLIB$methodName$0".
* @param renamedMethod the method to check
*/
public static boolean isCglibRenamedMethod(Method renamedMethod) {
String name = renamedMethod.getName();
if (name.startsWith(CGLIB_RENAMED_METHOD_PREFIX)) {
int i = name.length() - 1;
while (i >= 0 && Character.isDigit(name.charAt(i))) {
i--;
}
return (i > CGLIB_RENAMED_METHOD_PREFIX.length() && (i < name.length() - 1) && name.charAt(i) == '$');
}
return false;
}
/**
* Make the given method accessible, explicitly setting it accessible if
* necessary. The {@code setAccessible(true)} method is only called
* when actually necessary, to avoid unnecessary conflicts.
* @param method the method to make accessible
* @see java.lang.reflect.Method#setAccessible
*/
@SuppressWarnings("deprecation")
public static void makeAccessible(Method method) {
if ((!Modifier.isPublic(method.getModifiers()) ||
!Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) {
method.setAccessible(true);
}
}
// Field handling
/**
* Attempt to find a {@link Field field} on the supplied {@link Class} with the
* supplied {@code name}. Searches all superclasses up to {@link Object}.
* @param clazz the class to introspect
* @param name the name of the field
* @return the corresponding Field object, or {@code null} if not found
*/
@Nullable
public static Field findField(Class<?> clazz, String name) {
return findField(clazz, name, null);
}
/**
* Attempt to find a {@link Field field} on the supplied {@link Class} with the
* supplied {@code name} and/or {@link Class type}. Searches all superclasses
* up to {@link Object}.
* @param clazz the class to introspect
* @param name the name of the field (may be {@code null} if type is specified)
* @param type the type of the field (may be {@code null} if name is specified)
* @return the corresponding Field object, or {@code null} if not found
*/
@Nullable
public static Field findField(Class<?> clazz, @Nullable String name, @Nullable Class<?> type) {
Assert.notNull(clazz, "Class must not be null");
Assert.isTrue(name != null || type != null, "Either name or type of the field must be specified");
Class<?> searchType = clazz;
while (Object.class != searchType && searchType != null) {
Field[] fields = getDeclaredFields(searchType);
for (Field field : fields) {
if ((name == null || name.equals(field.getName())) &&
(type == null || type.equals(field.getType()))) {
return field;
}
}
searchType = searchType.getSuperclass();
}
return null;
}
/**
* Set the field represented by the supplied {@linkplain Field field object} on
* the specified {@linkplain Object target object} to the specified {@code value}.
* <p>In accordance with {@link Field#set(Object, Object)} semantics, the new value
* is automatically unwrapped if the underlying field has a primitive type.
* <p>This method does not support setting {@code static final} fields.
* <p>Thrown exceptions are handled via a call to {@link #handleReflectionException(Exception)}.
* @param field the field to set
* @param target the target object on which to set the field
* (or {@code null} for a static field)
* @param value the value to set (may be {@code null})
*/
public static void setField(Field field, @Nullable Object target, @Nullable Object value) {
try {
field.set(target, value);
}
catch (IllegalAccessException ex) {
handleReflectionException(ex);
}
}
/**
* Get the field represented by the supplied {@link Field field object} on the
* specified {@link Object target object}. In accordance with {@link Field#get(Object)}
* semantics, the returned value is automatically wrapped if the underlying field
* has a primitive type.
* <p>Thrown exceptions are handled via a call to {@link #handleReflectionException(Exception)}.
* @param field the field to get
* @param target the target object from which to get the field
* (or {@code null} for a static field)
* @return the field's current value
*/
@Nullable
public static Object getField(Field field, @Nullable Object target) {
try {
return field.get(target);
}
catch (IllegalAccessException ex) {
handleReflectionException(ex);
}
throw new IllegalStateException("Should never get here");
}
/**
* Invoke the given callback on all locally declared fields in the given class.
* @param clazz the target class to analyze
* @param fc the callback to invoke for each field
* @throws IllegalStateException if introspection fails
* @since 4.2
* @see #doWithFields
*/
public static void doWithLocalFields(Class<?> clazz, FieldCallback fc) {
for (Field field : getDeclaredFields(clazz)) {
try {
fc.doWith(field);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException("Not allowed to access field '" + field.getName() + "': " + ex);
}
}
}
/**
* Invoke the given callback on all fields in the target class, going up the
* class hierarchy to get all declared fields.
* @param clazz the target class to analyze
* @param fc the callback to invoke for each field
* @throws IllegalStateException if introspection fails
*/
public static void doWithFields(Class<?> clazz, FieldCallback fc) {
doWithFields(clazz, fc, null);
}
/**
* Invoke the given callback on all fields in the target class, going up the
* class hierarchy to get all declared fields.
* @param clazz the target class to analyze
* @param fc the callback to invoke for each field
* @param ff the filter that determines the fields to apply the callback to
* @throws IllegalStateException if introspection fails
*/
public static void doWithFields(Class<?> clazz, FieldCallback fc, @Nullable FieldFilter ff) {
// Keep backing up the inheritance hierarchy.
Class<?> targetClass = clazz;
do {
Field[] fields = getDeclaredFields(targetClass);
for (Field field : fields) {
if (ff != null && !ff.matches(field)) {
continue;
}
try {
fc.doWith(field);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException("Not allowed to access field '" + field.getName() + "': " + ex);
}
}
targetClass = targetClass.getSuperclass();
}
while (targetClass != null && targetClass != Object.class);
}
/**
* This variant retrieves {@link Class#getDeclaredFields()} from a local cache
* in order to avoid defensive array copying.
* @param clazz the class to introspect
* @return the cached array of fields
* @throws IllegalStateException if introspection fails
* @see Class#getDeclaredFields()
*/
private static Field[] getDeclaredFields(Class<?> clazz) {
Assert.notNull(clazz, "Class must not be null");
Field[] result = declaredFieldsCache.get(clazz);
if (result == null) {
try {
result = clazz.getDeclaredFields();
declaredFieldsCache.put(clazz, (result.length == 0 ? EMPTY_FIELD_ARRAY : result));
}
catch (Throwable ex) {
throw new IllegalStateException("Failed to introspect Class [" + clazz.getName() +
"] from ClassLoader [" + clazz.getClassLoader() + "]", ex);
}
}
return result;
}
/**
* 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
*/
public static void shallowCopyFieldState(final Object src, final Object dest) {
Assert.notNull(src, "Source for field copy cannot be null");
Assert.notNull(dest, "Destination for field copy cannot be null");
if (!src.getClass().isAssignableFrom(dest.getClass())) {
throw new IllegalArgumentException("Destination class [" + dest.getClass().getName() +
"] must be same or subclass as source class [" + src.getClass().getName() + "]");
}
doWithFields(src.getClass(), field -> {
makeAccessible(field);
Object srcValue = field.get(src);
field.set(dest, srcValue);
}, COPYABLE_FIELDS);
}
/**
* Determine whether the given field is a "public static final" constant.
* @param field the field to check
*/
public static boolean isPublicStaticFinal(Field field) {
int modifiers = field.getModifiers();
return (Modifier.isPublic(modifiers) && Modifier.isStatic(modifiers) && Modifier.isFinal(modifiers));
}
/**
* Make the given field accessible, explicitly setting it accessible if
* necessary. The {@code setAccessible(true)} method is only called
* when actually necessary, to avoid unnecessary conflicts.
* @param field the field to make accessible
* @see java.lang.reflect.Field#setAccessible
*/
@SuppressWarnings("deprecation")
public static void makeAccessible(Field field) {
if ((!Modifier.isPublic(field.getModifiers()) ||
!Modifier.isPublic(field.getDeclaringClass().getModifiers()) ||
Modifier.isFinal(field.getModifiers())) && !field.isAccessible()) {
field.setAccessible(true);
}
}
// Cache handling
/**
* Clear the internal method/field cache.
* @since 4.2.4
*/
public static void clearCache() {
declaredMethodsCache.clear();
declaredFieldsCache.clear();
}
/**
* Action to take on each method.
*/
@FunctionalInterface
public interface MethodCallback {
/**
* Perform an operation using the given method.
* @param method the method to operate on
*/
void doWith(Method method) throws IllegalArgumentException, IllegalAccessException;
}
/**
* Callback optionally used to filter methods to be operated on by a method callback.
*/
@FunctionalInterface
public interface MethodFilter {
/**
* Determine whether the given method matches.
* @param method the method to check
*/
boolean matches(Method method);
/**
* Create a composite filter based on this filter <em>and</em> the provided filter.
* <p>If this filter does not match, the next filter will not be applied.
* @param next the next {@code MethodFilter}
* @return a composite {@code MethodFilter}
* @throws IllegalArgumentException if the MethodFilter argument is {@code null}
* @since 5.3.2
*/
default MethodFilter and(MethodFilter next) {
Assert.notNull(next, "Next MethodFilter must not be null");
return method -> matches(method) && next.matches(method);
}
}
/**
* Callback interface invoked on each field in the hierarchy.
*/
@FunctionalInterface
public interface FieldCallback {
/**
* Perform an operation using the given field.
* @param field the field to operate on
*/
void doWith(Field field) throws IllegalArgumentException, IllegalAccessException;
}
/**
* Callback optionally used to filter fields to be operated on by a field callback.
*/
@FunctionalInterface
public interface FieldFilter {
/**
* Determine whether the given field matches.
* @param field the field to check
*/
boolean matches(Field field);
/**
* Create a composite filter based on this filter <em>and</em> the provided filter.
* <p>If this filter does not match, the next filter will not be applied.
* @param next the next {@code FieldFilter}
* @return a composite {@code FieldFilter}
* @throws IllegalArgumentException if the FieldFilter argument is {@code null}
* @since 5.3.2
*/
default FieldFilter and(FieldFilter next) {
Assert.notNull(next, "Next FieldFilter must not be null");
return field -> matches(field) && next.matches(field);
}
}
}
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