content: /*
   * Copyright 2002-2016 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
   *
   *      http://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 com.alibaba.bytekit.utils;
  
  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.sql.SQLException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.LinkedList;
  import java.util.List;
  
  /**
   * 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 {
  
  	/**
  	 * Naming prefix for CGLIB-renamed methods.
  	 * @see #isCglibRenamedMethod
  	 */
  	private static final String CGLIB_RENAMED_METHOD_PREFIX = "CGLIB$";
  
  	/**
  	 * 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
  	 */
  	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
  	 */
  	public static Field findField(Class<?> clazz, String name, Class<?> type) {
  		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 {@link Field field object} on the
  	 * specified {@link Object target object} to the specified {@code value}.
  	 * In accordance with {@link Field#set(Object, Object)} semantics, the new value
  	 * is automatically unwrapped 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 set
  	 * @param target the target object on which to set the field
  	 * @param value the value to set (may be {@code null})
  	 */
  	public static void setField(Field field, Object target, Object value) {
  		try {
  			field.set(target, value);
  		}
  		catch (IllegalAccessException ex) {
  			handleReflectionException(ex);
  			throw new IllegalStateException(
  					"Unexpected reflection exception - " + ex.getClass().getName() + ": " + ex.getMessage());
  		}
  	}
  
  	/**
  	 * 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
  	 * @return the field's current value
  	 */
  	public static Object getField(Field field, Object target) {
  		try {
  			return field.get(target);
  		}
  		catch (IllegalAccessException ex) {
  			handleReflectionException(ex);
  			throw new IllegalStateException(
  					"Unexpected reflection exception - " + ex.getClass().getName() + ": " + ex.getMessage());
  		}
  	}
  
  	/**
  	 * 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
  	 */
  	public static Method findMethod(Class<?> clazz, String name) {
  		return findMethod(clazz, name, new Class<?>[0]);
  	}
  
  	/**
  	 * 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
  	 */
  	public static Method findMethod(Class<?> clazz, String name, Class<?>... paramTypes) {
  		Class<?> searchType = clazz;
  		while (searchType != null) {
  			Method[] methods = (searchType.isInterface() ? searchType.getMethods() : getDeclaredMethods(searchType));
  			for (Method method : methods) {
  				if (name.equals(method.getName()) &&
  						(paramTypes == null || Arrays.equals(paramTypes, method.getParameterTypes()))) {
  					return method;
  				}
  			}
  			searchType = searchType.getSuperclass();
  		}
  		return null;
  	}
  
  	/**
  	 * 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[])
  	 */
  	public static Object invokeMethod(Method method, Object target) {
  		return invokeMethod(method, target, new Object[0]);
  	}
  
  	/**
  	 * 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
  	 */
  	public static Object invokeMethod(Method method, Object target, Object... args) {
  		try {
  			return method.invoke(target, args);
  		}
  		catch (Exception ex) {
  			handleReflectionException(ex);
  		}
  		throw new IllegalStateException("Should never get here");
  	}
  
  	/**
  	 * Invoke the specified JDBC API {@link Method} against the supplied target
  	 * object with no arguments.
  	 * @param method the method to invoke
  	 * @param target the target object to invoke the method on
  	 * @return the invocation result, if any
  	 * @throws SQLException the JDBC API SQLException to rethrow (if any)
  	 * @see #invokeJdbcMethod(java.lang.reflect.Method, Object, Object[])
  	 */
  	public static Object invokeJdbcMethod(Method method, Object target) throws SQLException {
  		return invokeJdbcMethod(method, target, new Object[0]);
  	}
  
  	/**
  	 * Invoke the specified JDBC API {@link Method} against the supplied target
  	 * object with the supplied arguments.
  	 * @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
  	 * @throws SQLException the JDBC API SQLException to rethrow (if any)
  	 * @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
  	 */
  	public static Object invokeJdbcMethod(Method method, Object target, Object... args) throws SQLException {
  		try {
  			return method.invoke(target, args);
  		}
  		catch (IllegalAccessException ex) {
  			handleReflectionException(ex);
  		}
  		catch (InvocationTargetException ex) {
  			if (ex.getTargetException() instanceof SQLException) {
  				throw (SQLException) ex.getTargetException();
  			}
  			handleInvocationTargetException(ex);
  		}
  		throw new IllegalStateException("Should never get here");
  	}
  
  	/**
  	 * Handle the given reflection 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 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: " + ex.getMessage());
  		}
  		if (ex instanceof InvocationTargetException) {
  			handleInvocationTargetException((InvocationTargetException) ex);
  		}
  		if (ex instanceof RuntimeException) {
  			throw (RuntimeException) ex;
  		}
  		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) {
  			throw (RuntimeException) ex;
  		}
  		if (ex instanceof Error) {
  			throw (Error) ex;
  		}
  		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 ex the exception to rethrow
  	 * @throws Exception the rethrown exception (in case of a checked exception)
  	 */
  	public static void rethrowException(Throwable ex) throws Exception {
  		if (ex instanceof Exception) {
  			throw (Exception) ex;
  		}
  		if (ex instanceof Error) {
  			throw (Error) ex;
  		}
  		throw new UndeclaredThrowableException(ex);
  	}
  
  	/**
  	 * 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) {
  		Class<?>[] declaredExceptions = method.getExceptionTypes();
  		for (Class<?> declaredException : declaredExceptions) {
  			if (declaredException.isAssignableFrom(exceptionType)) {
  				return true;
  			}
  		}
  		return false;
  	}
  
  	/**
  	 * 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));
  	}
  
  	/**
  	 * Determine whether the given method is an "equals" method.
  	 * @see java.lang.Object#equals(Object)
  	 */
  	public static boolean isEqualsMethod(Method method) {
  		if (method == null || !method.getName().equals("equals")) {
  			return false;
  		}
  		Class<?>[] paramTypes = method.getParameterTypes();
  		return (paramTypes.length == 1 && paramTypes[0] == Object.class);
  	}
  
  	/**
  	 * Determine whether the given method is a "hashCode" method.
  	 * @see java.lang.Object#hashCode()
  	 */
  	public static boolean isHashCodeMethod(Method method) {
  		return (method != null && method.getName().equals("hashCode") && method.getParameterTypes().length == 0);
  	}
  
  	/**
  	 * Determine whether the given method is a "toString" method.
  	 * @see java.lang.Object#toString()
  	 */
  	public static boolean isToStringMethod(Method method) {
  		return (method != null && method.getName().equals("toString") && method.getParameterTypes().length == 0);
  	}
  
  	/**
  	 * Determine whether the given method is originally declared by {@link java.lang.Object}.
  	 */
  	public static boolean isObjectMethod(Method method) {
  		if (method == null) {
  			return false;
  		}
  		try {
  			Object.class.getDeclaredMethod(method.getName(), method.getParameterTypes());
  			return true;
  		}
  		catch (Exception ex) {
  			return false;
  		}
  	}
  
  	/**
  	 * Determine whether the given method is a CGLIB 'renamed' method,
  	 * following the pattern "CGLIB$methodName$0".
  	 * @param renamedMethod the method to check
  	 * @see org.springframework.cglib.proxy.Enhancer#rename
  	 */
  	public static boolean isCglibRenamedMethod(Method renamedMethod) {
  		String name = renamedMethod.getName();
  		if (name.startsWith(CGLIB_RENAMED_METHOD_PREFIX)) {
  			int i = name.length() - 1;
  			while (i >= 0 && Character.isDigit(name.charAt(i))) {
  				i--;
  			}
  			return ((i > CGLIB_RENAMED_METHOD_PREFIX.length()) &&
  						(i < name.length() - 1) && name.charAt(i) == '$');
  		}
  		return false;
  	}
  
  	/**
  	 * Make the given field accessible, explicitly setting it accessible if
  	 * necessary. The {@code setAccessible(true)} method is only called
  	 * when actually necessary, to avoid unnecessary conflicts with a JVM
  	 * SecurityManager (if active).
  	 * @param field the field to make accessible
  	 * @see java.lang.reflect.Field#setAccessible
  	 */
  	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);
  		}
  	}
  
  	/**
  	 * 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 with a JVM
  	 * SecurityManager (if active).
  	 * @param method the method to make accessible
  	 * @see java.lang.reflect.Method#setAccessible
  	 */
  	public static void makeAccessible(Method method) {
  		if ((!Modifier.isPublic(method.getModifiers()) ||
  				!Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) {
  			method.setAccessible(true);
  		}
  	}
  
  	/**
  	 * 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 with a JVM
  	 * SecurityManager (if active).
  	 * @param ctor the constructor to make accessible
  	 * @see java.lang.reflect.Constructor#setAccessible
  	 */
  	public static void makeAccessible(Constructor<?> ctor) {
  		if ((!Modifier.isPublic(ctor.getModifiers()) ||
  				!Modifier.isPublic(ctor.getDeclaringClass().getModifiers())) && !ctor.isAccessible()) {
  			ctor.setAccessible(true);
  		}
  	}
  
  	/**
  	 * 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
  	 * @since 4.2
  	 * @see #doWithMethods
  	 */
  	public static void doWithLocalMethods(Class<?> clazz, MethodCallback mc) {
  		Method[] methods = getDeclaredMethods(clazz);
  		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
  	 * @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
  	 */
  	public static void doWithMethods(Class<?> clazz, MethodCallback mc, MethodFilter mf) {
  		// Keep backing up the inheritance hierarchy.
  		Method[] methods = getDeclaredMethods(clazz);
  		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);
  			}
  		}
  		if (clazz.getSuperclass() != null) {
  			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
  	 */
  	public static Method[] getAllDeclaredMethods(Class<?> leafClass) {
  		final List<Method> methods = new ArrayList<Method>(32);
  		doWithMethods(leafClass, new MethodCallback() {
  			@Override
  			public void doWith(Method method) {
  				methods.add(method);
  			}
  		});
  		return methods.toArray(new Method[methods.size()]);
  	}
  
  	/**
  	 * 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
  	 */
  	public static Method[] getUniqueDeclaredMethods(Class<?> leafClass) {
  		final List<Method> methods = new ArrayList<Method>(32);
  		doWithMethods(leafClass, new MethodCallback() {
  			@Override
  			public void doWith(Method method) {
  				boolean knownSignature = false;
  				Method methodBeingOverriddenWithCovariantReturnType = null;
  				for (Method existingMethod : methods) {
  					if (method.getName().equals(existingMethod.getName()) &&
  							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);
  				}
  			}
  		});
  		return methods.toArray(new Method[methods.size()]);
  	}
  
  	/**
  	 * This variant retrieves {@link Class#getDeclaredMethods()} from a local cache
  	 * in order to avoid the JVM's SecurityManager check and defensive array copying.
  	 * 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
  	 * @see Class#getDeclaredMethods()
  	 */
  	private static Method[] getDeclaredMethods(Class<?> clazz) {
  		Method[] result = null;
  		if (result == null) {
  			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;
  			}
  		}
  		return result;
  	}
  
  	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 LinkedList<Method>();
  					}
  					result.add(ifcMethod);
  				}
  			}
  		}
  		return result;
  	}
  
  	/**
  	 * 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
  	 * @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
  	 */
  	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
  	 */
  	public static void doWithFields(Class<?> clazz, FieldCallback fc, 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 the JVM's SecurityManager check and defensive array copying.
  	 * @param clazz the class to introspect
  	 * @return the cached array of fields
  	 * @see Class#getDeclaredFields()
  	 */
  	private static Field[] getDeclaredFields(Class<?> clazz) {
  		Field[] result = null;
  		if (result == null) {
  			result = clazz.getDeclaredFields();
  		}
  		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.
  	 */
  	public static void shallowCopyFieldState(final Object src, final Object dest) {
  		if (src == null) {
  			throw new IllegalArgumentException("Source for field copy cannot be null");
  		}
  		if (dest == null) {
  			throw new IllegalArgumentException("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(), new FieldCallback() {
  			@Override
  			public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {
  				makeAccessible(field);
  				Object srcValue = field.get(src);
  				field.set(dest, srcValue);
  			}
  		}, COPYABLE_FIELDS);
  	}
  
  
  	/**
  	 * Action to take on each method.
  	 */
  	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.
  	 */
  	public interface MethodFilter {
  
  		/**
  		 * Determine whether the given method matches.
  		 * @param method the method to check
  		 */
  		boolean matches(Method method);
  	}
  
  
  	/**
  	 * Callback interface invoked on each field in the hierarchy.
  	 */
  	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.
  	 */
  	public interface FieldFilter {
  
  		/**
  		 * Determine whether the given field matches.
  		 * @param field the field to check
  		 */
  		boolean matches(Field field);
  	}
  
  
  	/**
  	 * Pre-built FieldFilter that matches all non-static, non-final fields.
  	 */
  	public static final FieldFilter COPYABLE_FIELDS = new FieldFilter() {
  
  		@Override
  		public boolean matches(Field field) {
  			return !(Modifier.isStatic(field.getModifiers()) || Modifier.isFinal(field.getModifiers()));
  		}
  	};
  
  
  	/**
  	 * Pre-built MethodFilter that matches all non-bridge methods.
  	 */
  	public static final MethodFilter NON_BRIDGED_METHODS = new MethodFilter() {
  
  		@Override
  		public boolean matches(Method method) {
  			return !method.isBridge();
  		}
  	};
  
  
  	/**
  	 * Pre-built MethodFilter that matches all non-bridge methods
  	 * which are not declared on {@code java.lang.Object}.
  	 */
  	public static final MethodFilter USER_DECLARED_METHODS = new MethodFilter() {
  
  		@Override
  		public boolean matches(Method method) {
  			return (!method.isBridge() && method.getDeclaringClass() != Object.class);
  		}
  	};
  
  }
  