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/*
* Licensed to the Nervousync Studio (NSYC) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.nervousync.utils;
import java.lang.reflect.*;
import java.util.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The type Reflection utils.
*
* @author Steven Wee [email protected]
* @version $Revision : 1.0 $ $Date: Jan 13, 2010 4:26:58 PM $
*/
public final class ReflectionUtils {
private static final Logger LOGGER = LoggerFactory.getLogger(ReflectionUtils.class);
private ReflectionUtils() {
}
/**
* Parse field name from getter/setter method name
*
* @param methodName method name
* @return parsed field name
*/
public static String fieldName(final String methodName) {
String fieldName = null;
if (methodName != null) {
if (methodName.startsWith("get") || methodName.startsWith("set")) {
fieldName = methodName.substring(3);
} else if (methodName.startsWith("is")) {
fieldName = methodName.substring(2);
}
}
if (fieldName != null) {
fieldName = fieldName.substring(0, 1).toLowerCase() + fieldName.substring(1);
}
return fieldName;
}
/**
* Retrieve child enum define in given define class
*
* @param enumClass Define class
* @return enum data map
*/
public static Map parseEnum(final Class enumClass) {
Map enumMap = new HashMap<>();
if (enumClass != null && enumClass.isEnum()) {
Object[] constants = enumClass.getEnumConstants();
for (Object object : constants) {
enumMap.put(object.toString(), object);
}
}
return enumMap;
}
/**
* Gets all declared fields.
*
* @param clazz the clazz
* @return the all declared fields
*/
public static List getAllDeclaredFields(final Class clazz) {
if (clazz == null) {
return new ArrayList<>(0);
}
List fieldList = new ArrayList<>();
Arrays.stream(clazz.getDeclaredFields())
.filter(field -> !staticMember(field))
.forEach(fieldList::add);
if (clazz.getSuperclass() != null) {
ReflectionUtils.getAllDeclaredFields(clazz.getSuperclass())
.stream()
.filter(field -> !staticMember(field))
.forEach(fieldList::add);
}
return fieldList;
}
/**
* Set the field represented by the supplied {@link Field field object} on
* the specified {@link Object target object} to the specified
* value.
* In accordance with {@link 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
* {@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 null
*/
public static void setField(final Field field, final Object target, final 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.
*
Thrown exceptions are handled via a call to
* {@link #handleReflectionException(Exception)}.
*
* @param fieldName the name of field to get
* @param target the target object from which to get the field
* @return the field's current value
*/
public static Object getFieldValue(final String fieldName, final Object target) {
if (fieldName == null || target == null) {
return null;
}
try {
Method getMethod = ClassUtils.getterMethod(fieldName, target.getClass());
if (getMethod != null) {
return getMethod.invoke(target);
} else {
Field field = getFieldIfAvailable(target.getClass(), fieldName);
return ReflectionUtils.getFieldValue(field, target);
}
} catch (Exception 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.
*
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 getFieldValue(final Field field, final Object target) {
if (field == null || target == null) {
return null;
}
try {
makeAccessible(field);
return field.get(target);
} catch (IllegalAccessException ex) {
handleReflectionException(ex);
throw new IllegalStateException(
"Unexpected reflection exception - " + ex.getClass().getName() + ": " + ex.getMessage());
}
}
/**
* Execute method object.
*
* @param methodName the method name
* @param target the target
* @return the object
* @throws IllegalArgumentException the illegal argument exception
*/
public static Object executeMethod(final String methodName, final Object target)
throws IllegalArgumentException {
return executeMethod(methodName, target, new Class[]{});
}
/**
* Execute method object.
*
* @param methodName the method name
* @param target the target
* @param paramClasses the param classes
* @param args the args
* @return the object
* @throws IllegalArgumentException the illegal argument exception
*/
public static Object executeMethod(final String methodName, final Object target,
final Class[] paramClasses, final Object... args)
throws IllegalArgumentException {
boolean noParam = paramClasses == null || paramClasses.length == 0;
Method method = noParam
? ClassUtils.findMethod(target.getClass(), methodName)
: ClassUtils.findMethod(target.getClass(), methodName, paramClasses);
if (method == null) {
throw new IllegalArgumentException("Method named : " + methodName + " does not exists");
}
ReflectionUtils.makeAccessible(method);
Object returnObj = noParam ? invokeMethod(method, target) : invokeMethod(method, target, args);
return method.getReturnType().equals(void.class) ? null : returnObj;
}
/**
* Invoke the specified {@link Method} against the supplied target object
* with no arguments.
* The target object can be null when invoking a static {@link Method}.
*
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(final Method method, final Object target) {
return invokeMethod(method, target, null);
}
/**
* Invoke the specified {@link Method} against the supplied target object
* with the supplied arguments.
* The target object can be null when invoking a static {@link Method}.
*
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 (maybe null)
* @return the invocation result, if any
*/
public static Object invokeMethod(final Method method, final Object target, final Object[] args) {
try {
return method.invoke(target, args);
} catch (Exception ex) {
handleReflectionException(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.
*
Throws the underlying RuntimeException or Error in case of an
* InvocationTargetException with such a root cause.
* Throw an IllegalStateException with an appropriate message else.
*
* @param ex the reflection exception to handle
*/
public static void handleReflectionException(final 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;
}
handleUnexpectedException(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.
*
* @param ex the invocation target exception to handle
*/
public static void handleInvocationTargetException(final InvocationTargetException ex) {
rethrowRuntimeException(ex.getTargetException());
}
/**
* Rethrow the given {@link Throwable exception}, which is presumably the
* target exception of an {@link 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 {@link RuntimeException}
* or {@link Error} if appropriate; otherwise, throws an
* {@link IllegalStateException}.
*
* @param ex the exception to rethrow
* @throws RuntimeException the rethrown exception
*/
public static void rethrowRuntimeException(final Throwable ex) {
if (ex instanceof RuntimeException) {
throw (RuntimeException) ex;
}
if (ex instanceof Error) {
throw (Error) ex;
}
handleUnexpectedException(ex);
}
/**
* Rethrow the given {@link Throwable exception}, which is presumably the
* target exception of an {@link 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 {@link Exception} or
* {@link Error} if appropriate; otherwise, throws an
* {@link IllegalStateException}.
*
* @param ex the exception to rethrow
* @throws Exception the rethrown exception (in case of a checked exception)
*/
public static void rethrowException(final Throwable ex) throws Exception {
if (ex instanceof Exception) {
throw (Exception) ex;
}
if (ex instanceof Error) {
throw (Error) ex;
}
handleUnexpectedException(ex);
}
/**
* Determine whether the given method explicitly declares the given exception
* or one of its superclasses, which means that an exception to that type
* can be propagated as-is within a reflective invocation.
*
* @param method the declaring method
* @param exceptionType the exception to throw
* @return true if the exception can be thrown as-is; false if it needs to be wrapped
*/
public static boolean declaresException(final Method method, final Class exceptionType) {
if (method == null) {
throw new IllegalArgumentException("Method must not be null");
}
Class[] declaredExceptions = method.getExceptionTypes();
for (Class declaredException : declaredExceptions) {
if (declaredException.isAssignableFrom(exceptionType)) {
return Boolean.TRUE;
}
}
return Boolean.FALSE;
}
/**
* Determine whether the given field/method is a "public" constant.
*
* @param member the field/method to check
* @return is a "public" constant.
*/
public static boolean publicMember(final Member member) {
return Optional.ofNullable(member)
.map(checkMember -> Modifier.isPublic(checkMember.getModifiers()))
.orElse(Boolean.FALSE);
}
/**
* Determine whether the given field/method is a "protected" constant.
*
* @param member the field/method to check
* @return is a "protected" constant.
*/
public static boolean protectedMember(final Member member) {
return Optional.ofNullable(member)
.map(checkMember -> Modifier.isProtected(checkMember.getModifiers()))
.orElse(Boolean.FALSE);
}
/**
* Determine whether the given field/method is a "protected" constant.
*
* @param member the field/method to check
* @return is a "protected" constant.
*/
public static boolean privateMember(final Member member) {
return Optional.ofNullable(member)
.map(checkMember -> Modifier.isPrivate(checkMember.getModifiers()))
.orElse(Boolean.FALSE);
}
/**
* Determine whether the given field/method is a "static" constant.
*
* @param member the field/method to check
* @return is a "static" constant.
*/
public static boolean staticMember(final Member member) {
return Optional.ofNullable(member)
.map(checkMember -> Modifier.isStatic(checkMember.getModifiers()))
.orElse(Boolean.FALSE);
}
/**
* Determine whether the given field/method is a "final" constant.
*
* @param member the field/method to check
* @return is a "final" constant.
*/
public static boolean finalMember(final Member member) {
return Optional.ofNullable(member)
.map(checkMember -> Modifier.isFinal(checkMember.getModifiers()))
.orElse(Boolean.FALSE);
}
/**
* Determine whether the given field is a "public static final" constant.
*
* @param member the field/method to check
* @return is a "public static final" constant.
*/
public static boolean isPublicStaticFinal(final Member member) {
return publicMember(member) && staticMember(member) && finalMember(member);
}
/**
* 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).
*
* @param field the field to make accessible
* @see java.lang.reflect.Field#setAccessible
*/
public static void makeAccessible(final Field field) {
if (privateMember(field) || protectedMember(field) ||
!Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
field.setAccessible(Boolean.TRUE);
}
}
/**
* 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).
*
* @param method the method to make accessible
* @see java.lang.reflect.Method#setAccessible
*/
public static void makeAccessible(final Method method) {
if (privateMember(method) || protectedMember(method) ||
!Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
method.setAccessible(true);
}
}
/**
* 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).
*
* @param ctor the constructor to make accessible
* @see java.lang.reflect.Constructor#setAccessible
*/
public static void makeAccessible(final Constructor ctor) {
if (!Modifier.isPublic(ctor.getModifiers()) ||
!Modifier.isPublic(ctor.getDeclaringClass().getModifiers())) {
ctor.setAccessible(true);
}
}
/**
* 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 {@link MethodFilter}.
*
* @param targetClass class to start looking at
* @param callback the callback to invoke for each method
* @throws IllegalArgumentException the illegal argument exception
* @see #doWithMethods(Class, MethodCallback, MethodFilter) #doWithMethods(Class, MethodCallback, MethodFilter)
*/
public static void doWithMethods(Class targetClass, final MethodCallback callback)
throws IllegalArgumentException {
doWithMethods(targetClass, callback, null);
}
/**
* 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 {@link MethodFilter}.
*
* @param targetClass class to start looking at
* @param callback the callback to invoke for each method
* @param filter the filter that determines the methods to apply the callback to
* @throws IllegalArgumentException the illegal argument exception
*/
public static void doWithMethods(Class targetClass, final MethodCallback callback, final MethodFilter filter)
throws IllegalArgumentException {
// Keep backing up the inheritance hierarchy.
do {
Arrays.stream(targetClass.getDeclaredMethods())
.filter(method -> (filter == null || filter.matches(method)))
.forEach(method -> {
try {
callback.doWith(method);
} catch (IllegalArgumentException ex) {
throw new IllegalStateException(
"Shouldn't be illegal argument method '" + method.getName() + "': " + ex);
}
});
targetClass = targetClass.getSuperclass();
}
while (targetClass != null);
}
/**
* Get all declared methods on the given class and all superclasses.
* Leaf class methods are included first.
*
* @param clazz given class
* @return All declared method arrays
* @throws IllegalArgumentException the illegal argument exception
*/
public static Method[] getAllDeclaredMethods(final Class clazz) throws IllegalArgumentException {
final List list = new ArrayList<>(32);
doWithMethods(clazz, list::add);
return list.toArray(new Method[0]);
}
/**
* Parse component type class.
*
* @param method the method
* @return the class
*/
public static Class componentType(final Method method) {
Class returnClass = method.getReturnType();
Class returnItem = null;
if (returnClass.isArray()) {
returnItem = returnClass.getComponentType();
} else if (List.class.isAssignableFrom(returnClass)) {
returnItem = (Class) ((ParameterizedType) method.getGenericReturnType()).getActualTypeArguments()[0];
}
return returnItem;
}
/**
* Invoke the given callback on all fields in the target class,
* going up the class hierarchy to get all declared fields.
*
* @param targetClass the target class to analyze
* @param callback the callback to invoke for each field
* @throws IllegalArgumentException the illegal argument exception
*/
public static void doWithFields(final Class targetClass, final FieldCallback callback)
throws IllegalArgumentException {
doWithFields(targetClass, callback, null);
}
/**
* Invoke the given callback on all fields in the target class,
* going up the class hierarchy to get all declared fields.
*
* @param targetClass the target class to analyze
* @param callback the callback to invoke for each field
* @param filter the filter that determines the fields to apply the callback to
* @throws IllegalArgumentException the illegal argument exception
*/
public static void doWithFields(final Class targetClass, final FieldCallback callback, final FieldFilter filter)
throws IllegalArgumentException {
// Keep backing up the inheritance hierarchy.
Class currentClass = targetClass;
do {
// Copy each field declared on this class unless it's static or file.
Field[] fields = currentClass.getDeclaredFields();
for (Field field : fields) {
// Skip static and final fields.
if (filter != null && filter.matches(field)) {
try {
callback.doWith(field);
} catch (IllegalAccessException ex) {
throw new IllegalStateException(
"Shouldn't be illegal to access field '" + field.getName() + "': " + ex);
}
}
}
currentClass = currentClass.getSuperclass();
}
while (currentClass != null && currentClass != Object.class);
}
/**
* 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.
*
* @param src source object
* @param dest target object
* @throws IllegalArgumentException if the arguments are incompatible
*/
public static void shallowCopyFieldState(final Object src, final Object dest) throws IllegalArgumentException {
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(), field -> {
makeAccessible(field);
Object srcValue = field.get(src);
field.set(dest, srcValue);
}, COPYABLE_FIELDS);
}
/**
* Retrieve the field object if available
*
* @param clazz Define class
* @param fieldName field name
* @return Retrieve the field object or null if not exists
*/
public static Field getFieldIfAvailable(final Class clazz, final String fieldName) {
if (clazz == null) {
return null;
}
try {
return clazz.getDeclaredField(fieldName);
} catch (Exception e) {
return getFieldIfAvailable(clazz.getSuperclass(), fieldName);
}
}
/**
* Set field value values
*
* @param target target object
* @param parameterMap field value map
*/
public static void setField(final Object target, final Map parameterMap) {
if (target == null || parameterMap == null) {
return;
}
parameterMap.forEach((key, value) -> {
Object fieldValue;
if (value.getClass().isArray()) {
if (((Object[]) value).length == 1) {
fieldValue = ((Object[]) value)[0];
} else {
fieldValue = value;
}
} else {
fieldValue = value;
}
setField(key, target, fieldValue);
});
}
/**
* Set field value
*
* @param fieldName field name
* @param target target object
* @param value field value
*/
public static void setField(final String fieldName, final Object target, final Object value) {
try {
Method setMethod = ClassUtils.setterMethod(fieldName, target.getClass());
if (setMethod != null) {
setMethod.invoke(target, value);
} else {
Field field = getFieldIfAvailable(target.getClass(), fieldName);
if (field != null) {
makeAccessible(field);
setField(field, target, value);
}
}
} catch (Exception e) {
if (ReflectionUtils.LOGGER.isDebugEnabled()) {
ReflectionUtils.LOGGER.debug("Convert to Object set field value error! ", e);
if (value != null) {
ReflectionUtils.LOGGER.debug(fieldName + ":" + value.getClass().getName());
}
}
}
}
/**
* Throws an IllegalStateException with the given exception as root cause.
*
* @param ex the unexpected exception
*/
private static void handleUnexpectedException(final Throwable ex) {
// Needs to avoid the chained constructor for JDK 1.4 compatibility.
throw new IllegalStateException("Unexpected exception thrown", ex);
}
/**
* Action to take on each method.
*/
public interface MethodCallback {
/**
* Perform an operation using the given method.
*
* @param method the method to operate on
* @throws IllegalArgumentException @see java.lang.IllegalArgumentException
*/
void doWith(Method method) throws IllegalArgumentException;
}
/**
* Callback optionally used to method fields to be operated on by a method callback.
*/
public interface MethodFilter {
/**
* Determine whether the given method matches.
*
* @param method the method to check
* @return check result
*/
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
* @throws IllegalArgumentException @see java.lang.IllegalArgumentException
* @throws IllegalAccessException @see java.lang.IllegalAccessException
*/
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
* @return check result
*/
boolean matches(Field field);
}
/**
* 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()));
}