/* * Copyright 2002-2024 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.beans; import java.beans.ConstructorProperties; import java.beans.PropertyDescriptor; import java.beans.PropertyEditor; import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.lang.reflect.Type; import java.util.Arrays; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import kotlin.jvm.JvmClassMappingKt; import kotlin.jvm.JvmInline; import kotlin.reflect.KClass; import kotlin.reflect.KFunction; import kotlin.reflect.KParameter; import kotlin.reflect.full.KAnnotatedElements; import kotlin.reflect.full.KClasses; import kotlin.reflect.jvm.KCallablesJvm; import kotlin.reflect.jvm.ReflectJvmMapping; import org.springframework.core.DefaultParameterNameDiscoverer; import org.springframework.core.KotlinDetector; import org.springframework.core.MethodParameter; import org.springframework.core.ParameterNameDiscoverer; import org.springframework.core.ResolvableType; import org.springframework.lang.Nullable; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; import org.springframework.util.CollectionUtils; import org.springframework.util.ConcurrentReferenceHashMap; import org.springframework.util.ReflectionUtils; import org.springframework.util.StringUtils; /** * Static convenience methods for JavaBeans: for instantiating beans, * checking bean property types, copying bean properties, etc. * *
Mainly for internal use within the framework, but to some degree also
* useful for application classes. Consider
* Apache Commons BeanUtils,
* BULL - Bean Utils Light Library,
* or similar third-party frameworks for more comprehensive bean utilities.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Rob Harrop
* @author Sam Brannen
* @author Sebastien Deleuze
*/
public abstract class BeanUtils {
private static final ParameterNameDiscoverer parameterNameDiscoverer =
new DefaultParameterNameDiscoverer();
private static final Set Note that this method tries to set the constructor accessible
* if given a non-accessible (that is, non-public) constructor.
* @param clazz the class to instantiate
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated.
* The cause may notably indicate a {@link NoSuchMethodException} if no
* primary/default constructor was found, a {@link NoClassDefFoundError}
* or other {@link LinkageError} in case of an unresolvable class definition
* (e.g. due to a missing dependency at runtime), or an exception thrown
* from the constructor invocation itself.
* @see Constructor#newInstance
*/
public static Useful in cases where the type of the class to instantiate (clazz) is not
* available, but the type desired (assignableTo) is known.
* Note that this method tries to set the constructor accessible if given a
* non-accessible (that is, non-public) constructor.
* @param clazz class to instantiate
* @param assignableTo type that clazz must be assignableTo
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated
* @see Constructor#newInstance
*/
@SuppressWarnings("unchecked")
public static Note that this method tries to set the constructor accessible if given a
* non-accessible (that is, non-public) constructor, and supports Kotlin classes
* with optional parameters and default values.
* @param ctor the constructor to instantiate
* @param args the constructor arguments to apply (use {@code null} for an unspecified
* parameter, Kotlin optional parameters and Java primitive types are supported)
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated
* @see Constructor#newInstance
*/
public static Checks {@code Class.getMethod} first, falling back to
* {@code findDeclaredMethod}. This allows to find public methods
* without issues even in environments with restricted Java security settings.
* @param clazz the class to check
* @param methodName the name of the method to find
* @param paramTypes the parameter types of the method to find
* @return the Method object, or {@code null} if not found
* @see Class#getMethod
* @see #findDeclaredMethod
*/
@Nullable
public static Method findMethod(Class> clazz, String methodName, Class>... paramTypes) {
try {
return clazz.getMethod(methodName, paramTypes);
}
catch (NoSuchMethodException ex) {
return findDeclaredMethod(clazz, methodName, paramTypes);
}
}
/**
* Find a method with the given method name and the given parameter types,
* declared on the given class or one of its superclasses. Will return a public,
* protected, package access, or private method.
* Checks {@code Class.getDeclaredMethod}, cascading upwards to all superclasses.
* @param clazz the class to check
* @param methodName the name of the method to find
* @param paramTypes the parameter types of the method to find
* @return the Method object, or {@code null} if not found
* @see Class#getDeclaredMethod
*/
@Nullable
public static Method findDeclaredMethod(Class> clazz, String methodName, Class>... paramTypes) {
try {
return clazz.getDeclaredMethod(methodName, paramTypes);
}
catch (NoSuchMethodException ex) {
if (clazz.getSuperclass() != null) {
return findDeclaredMethod(clazz.getSuperclass(), methodName, paramTypes);
}
return null;
}
}
/**
* Find a method with the given method name and minimal parameters (best case: none),
* declared on the given class or one of its superclasses. Prefers public methods,
* but will return a protected, package access, or private method too.
* Checks {@code Class.getMethods} first, falling back to
* {@code findDeclaredMethodWithMinimalParameters}. This allows for finding public
* methods without issues even in environments with restricted Java security settings.
* @param clazz the class to check
* @param methodName the name of the method to find
* @return the Method object, or {@code null} if not found
* @throws IllegalArgumentException if methods of the given name were found but
* could not be resolved to a unique method with minimal parameters
* @see Class#getMethods
* @see #findDeclaredMethodWithMinimalParameters
*/
@Nullable
public static Method findMethodWithMinimalParameters(Class> clazz, String methodName)
throws IllegalArgumentException {
Method targetMethod = findMethodWithMinimalParameters(clazz.getMethods(), methodName);
if (targetMethod == null) {
targetMethod = findDeclaredMethodWithMinimalParameters(clazz, methodName);
}
return targetMethod;
}
/**
* Find a method with the given method name and minimal parameters (best case: none),
* declared on the given class or one of its superclasses. Will return a public,
* protected, package access, or private method.
* Checks {@code Class.getDeclaredMethods}, cascading upwards to all superclasses.
* @param clazz the class to check
* @param methodName the name of the method to find
* @return the Method object, or {@code null} if not found
* @throws IllegalArgumentException if methods of the given name were found but
* could not be resolved to a unique method with minimal parameters
* @see Class#getDeclaredMethods
*/
@Nullable
public static Method findDeclaredMethodWithMinimalParameters(Class> clazz, String methodName)
throws IllegalArgumentException {
Method targetMethod = findMethodWithMinimalParameters(clazz.getDeclaredMethods(), methodName);
if (targetMethod == null && clazz.getSuperclass() != null) {
targetMethod = findDeclaredMethodWithMinimalParameters(clazz.getSuperclass(), methodName);
}
return targetMethod;
}
/**
* Find a method with the given method name and minimal parameters (best case: none)
* in the given list of methods.
* @param methods the methods to check
* @param methodName the name of the method to find
* @return the Method object, or {@code null} if not found
* @throws IllegalArgumentException if methods of the given name were found but
* could not be resolved to a unique method with minimal parameters
*/
@Nullable
public static Method findMethodWithMinimalParameters(Method[] methods, String methodName)
throws IllegalArgumentException {
Method targetMethod = null;
int numMethodsFoundWithCurrentMinimumArgs = 0;
for (Method method : methods) {
if (method.getName().equals(methodName)) {
int numParams = method.getParameterCount();
if (targetMethod == null || numParams < targetMethod.getParameterCount()) {
targetMethod = method;
numMethodsFoundWithCurrentMinimumArgs = 1;
}
else if (!method.isBridge() && targetMethod.getParameterCount() == numParams) {
if (targetMethod.isBridge()) {
// Prefer regular method over bridge...
targetMethod = method;
}
else {
// Additional candidate with same length
numMethodsFoundWithCurrentMinimumArgs++;
}
}
}
}
if (numMethodsFoundWithCurrentMinimumArgs > 1) {
throw new IllegalArgumentException("Cannot resolve method '" + methodName +
"' to a unique method. Attempted to resolve to overloaded method with " +
"the least number of parameters but there were " +
numMethodsFoundWithCurrentMinimumArgs + " candidates.");
}
return targetMethod;
}
/**
* Parse a method signature in the form {@code methodName[([arg_list])]},
* where {@code arg_list} is an optional, comma-separated list of fully-qualified
* type names, and attempts to resolve that signature against the supplied {@code Class}.
* When not supplying an argument list ({@code methodName}) the method whose name
* matches and has the least number of parameters will be returned. When supplying an
* argument type list, only the method whose name and argument types match will be returned.
* Note then that {@code methodName} and {@code methodName()} are not
* resolved in the same way. The signature {@code methodName} means the method called
* {@code methodName} with the least number of arguments, whereas {@code methodName()}
* means the method called {@code methodName} with exactly 0 arguments.
* If no method can be found, then {@code null} is returned.
* @param signature the method signature as String representation
* @param clazz the class to resolve the method signature against
* @return the resolved Method
* @see #findMethod
* @see #findMethodWithMinimalParameters
*/
@Nullable
public static Method resolveSignature(String signature, Class> clazz) {
Assert.hasText(signature, "'signature' must not be empty");
Assert.notNull(clazz, "Class must not be null");
int startParen = signature.indexOf('(');
int endParen = signature.indexOf(')');
if (startParen > -1 && endParen == -1) {
throw new IllegalArgumentException("Invalid method signature '" + signature +
"': expected closing ')' for args list");
}
else if (startParen == -1 && endParen > -1) {
throw new IllegalArgumentException("Invalid method signature '" + signature +
"': expected opening '(' for args list");
}
else if (startParen == -1) {
return findMethodWithMinimalParameters(clazz, signature);
}
else {
String methodName = signature.substring(0, startParen);
String[] parameterTypeNames =
StringUtils.commaDelimitedListToStringArray(signature.substring(startParen + 1, endParen));
Class>[] parameterTypes = new Class>[parameterTypeNames.length];
for (int i = 0; i < parameterTypeNames.length; i++) {
String parameterTypeName = parameterTypeNames[i].trim();
try {
parameterTypes[i] = ClassUtils.forName(parameterTypeName, clazz.getClassLoader());
}
catch (Throwable ex) {
throw new IllegalArgumentException("Invalid method signature: unable to resolve type [" +
parameterTypeName + "] for argument " + i + ". Root cause: " + ex);
}
}
return findMethod(clazz, methodName, parameterTypes);
}
}
/**
* Retrieve the JavaBeans {@code PropertyDescriptor}s of a given class.
* @param clazz the Class to retrieve the PropertyDescriptors for
* @return an array of {@code PropertyDescriptors} for the given class
* @throws BeansException if PropertyDescriptor look fails
*/
public static PropertyDescriptor[] getPropertyDescriptors(Class> clazz) throws BeansException {
return CachedIntrospectionResults.forClass(clazz).getPropertyDescriptors();
}
/**
* Retrieve the JavaBeans {@code PropertyDescriptors} for the given property.
* @param clazz the Class to retrieve the PropertyDescriptor for
* @param propertyName the name of the property
* @return the corresponding PropertyDescriptor, or {@code null} if none
* @throws BeansException if PropertyDescriptor lookup fails
*/
@Nullable
public static PropertyDescriptor getPropertyDescriptor(Class> clazz, String propertyName) throws BeansException {
return CachedIntrospectionResults.forClass(clazz).getPropertyDescriptor(propertyName);
}
/**
* Find a JavaBeans {@code PropertyDescriptor} for the given method,
* with the method either being the read method or the write method for
* that bean property.
* @param method the method to find a corresponding PropertyDescriptor for,
* introspecting its declaring class
* @return the corresponding PropertyDescriptor, or {@code null} if none
* @throws BeansException if PropertyDescriptor lookup fails
*/
@Nullable
public static PropertyDescriptor findPropertyForMethod(Method method) throws BeansException {
return findPropertyForMethod(method, method.getDeclaringClass());
}
/**
* Find a JavaBeans {@code PropertyDescriptor} for the given method,
* with the method either being the read method or the write method for
* that bean property.
* @param method the method to find a corresponding PropertyDescriptor for
* @param clazz the (most specific) class to introspect for descriptors
* @return the corresponding PropertyDescriptor, or {@code null} if none
* @throws BeansException if PropertyDescriptor lookup fails
* @since 3.2.13
*/
@Nullable
public static PropertyDescriptor findPropertyForMethod(Method method, Class> clazz) throws BeansException {
Assert.notNull(method, "Method must not be null");
PropertyDescriptor[] pds = getPropertyDescriptors(clazz);
for (PropertyDescriptor pd : pds) {
if (method.equals(pd.getReadMethod()) || method.equals(pd.getWriteMethod())) {
return pd;
}
}
return null;
}
/**
* Find a JavaBeans PropertyEditor following the 'Editor' suffix convention
* (e.g. "mypackage.MyDomainClass" → "mypackage.MyDomainClassEditor").
* Compatible to the standard JavaBeans convention as implemented by
* {@link java.beans.PropertyEditorManager} but isolated from the latter's
* registered default editors for primitive types.
* @param targetType the type to find an editor for
* @return the corresponding editor, or {@code null} if none found
*/
@Nullable
public static PropertyEditor findEditorByConvention(@Nullable Class> targetType) {
if (targetType == null || targetType.isArray() || unknownEditorTypes.contains(targetType)) {
return null;
}
ClassLoader cl = targetType.getClassLoader();
if (cl == null) {
try {
cl = ClassLoader.getSystemClassLoader();
if (cl == null) {
return null;
}
}
catch (Throwable ex) {
// e.g. AccessControlException on Google App Engine
return null;
}
}
String targetTypeName = targetType.getName();
String editorName = targetTypeName + "Editor";
try {
Class> editorClass = cl.loadClass(editorName);
if (editorClass != null) {
if (!PropertyEditor.class.isAssignableFrom(editorClass)) {
unknownEditorTypes.add(targetType);
return null;
}
return (PropertyEditor) instantiateClass(editorClass);
}
// Misbehaving ClassLoader returned null instead of ClassNotFoundException
// - fall back to unknown editor type registration below
}
catch (ClassNotFoundException ex) {
// Ignore - fall back to unknown editor type registration below
}
unknownEditorTypes.add(targetType);
return null;
}
/**
* Determine the bean property type for the given property from the
* given classes/interfaces, if possible.
* @param propertyName the name of the bean property
* @param beanClasses the classes to check against
* @return the property type, or {@code Object.class} as fallback
*/
public static Class> findPropertyType(String propertyName, @Nullable Class>... beanClasses) {
if (beanClasses != null) {
for (Class> beanClass : beanClasses) {
PropertyDescriptor pd = getPropertyDescriptor(beanClass, propertyName);
if (pd != null) {
return pd.getPropertyType();
}
}
}
return Object.class;
}
/**
* Determine whether the specified property has a unique write method,
* i.e. is writable but does not declare overloaded setter methods.
* @param pd the PropertyDescriptor for the property
* @return {@code true} if writable and unique, {@code false} otherwise
* @since 6.1.4
*/
public static boolean hasUniqueWriteMethod(PropertyDescriptor pd) {
if (pd instanceof GenericTypeAwarePropertyDescriptor gpd) {
return gpd.hasUniqueWriteMethod();
}
else {
return (pd.getWriteMethod() != null);
}
}
/**
* Obtain a new MethodParameter object for the write method of the
* specified property.
* @param pd the PropertyDescriptor for the property
* @return a corresponding MethodParameter object
*/
public static MethodParameter getWriteMethodParameter(PropertyDescriptor pd) {
if (pd instanceof GenericTypeAwarePropertyDescriptor gpd) {
return new MethodParameter(gpd.getWriteMethodParameter());
}
else {
Method writeMethod = pd.getWriteMethod();
Assert.state(writeMethod != null, "No write method available");
return new MethodParameter(writeMethod, 0);
}
}
/**
* Determine required parameter names for the given constructor,
* considering the JavaBeans {@link ConstructorProperties} annotation
* as well as Spring's {@link DefaultParameterNameDiscoverer}.
* @param ctor the constructor to find parameter names for
* @return the parameter names (matching the constructor's parameter count)
* @throws IllegalStateException if the parameter names are not resolvable
* @since 5.3
* @see ConstructorProperties
* @see DefaultParameterNameDiscoverer
*/
public static String[] getParameterNames(Constructor> ctor) {
ConstructorProperties cp = ctor.getAnnotation(ConstructorProperties.class);
String[] paramNames = (cp != null ? cp.value() : parameterNameDiscoverer.getParameterNames(ctor));
Assert.state(paramNames != null, () -> "Cannot resolve parameter names for constructor " + ctor);
Assert.state(paramNames.length == ctor.getParameterCount(),
() -> "Invalid number of parameter names: " + paramNames.length + " for constructor " + ctor);
return paramNames;
}
/**
* Check if the given type represents a "simple" property: a simple value
* type or an array of simple value types.
* See {@link #isSimpleValueType(Class)} for the definition of simple
* value type.
* Used to determine properties to check for a "simple" dependency-check.
* @param type the type to check
* @return whether the given type represents a "simple" property
* @see org.springframework.beans.factory.support.RootBeanDefinition#DEPENDENCY_CHECK_SIMPLE
* @see org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#checkDependencies
* @see #isSimpleValueType(Class)
*/
public static boolean isSimpleProperty(Class> type) {
Assert.notNull(type, "'type' must not be null");
return isSimpleValueType(type) || (type.isArray() && isSimpleValueType(type.componentType()));
}
/**
* Check if the given type represents a "simple" value type for
* bean property and data binding purposes:
* a primitive or primitive wrapper, an {@code Enum}, a {@code String}
* or other {@code CharSequence}, a {@code Number}, a {@code Date},
* a {@code Temporal}, a {@code UUID}, a {@code URI}, a {@code URL},
* a {@code Locale}, or a {@code Class}.
* {@code Void} and {@code void} are not considered simple value types.
* As of 6.1, this method delegates to {@link ClassUtils#isSimpleValueType}
* as-is but could potentially add further rules for bean property purposes.
* @param type the type to check
* @return whether the given type represents a "simple" value type
* @see #isSimpleProperty(Class)
* @see ClassUtils#isSimpleValueType(Class)
*/
public static boolean isSimpleValueType(Class> type) {
return ClassUtils.isSimpleValueType(type);
}
/**
* Copy the property values of the given source bean into the target bean.
* Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* This is just a convenience method. For more complex transfer needs,
* consider using a full {@link BeanWrapper}.
* As of Spring Framework 5.3, this method honors generic type information
* when matching properties in the source and target objects.
* The following table provides a non-exhaustive set of examples of source
* and target property types that can be copied as well as source and target
* property types that cannot be copied.
* Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* This is just a convenience method. For more complex transfer needs,
* consider using a full {@link BeanWrapper}.
* As of Spring Framework 5.3, this method honors generic type information
* when matching properties in the source and target objects. See the
* documentation for {@link #copyProperties(Object, Object)} for details.
* @param source the source bean
* @param target the target bean
* @param editable the class (or interface) to restrict property setting to
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
public static void copyProperties(Object source, Object target, Class> editable) throws BeansException {
copyProperties(source, target, editable, (String[]) null);
}
/**
* Copy the property values of the given source bean into the given target bean,
* ignoring the given "ignoreProperties".
* Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* This is just a convenience method. For more complex transfer needs,
* consider using a full {@link BeanWrapper}.
* As of Spring Framework 5.3, this method honors generic type information
* when matching properties in the source and target objects. See the
* documentation for {@link #copyProperties(Object, Object)} for details.
* @param source the source bean
* @param target the target bean
* @param ignoreProperties array of property names to ignore
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
public static void copyProperties(Object source, Object target, String... ignoreProperties) throws BeansException {
copyProperties(source, target, null, ignoreProperties);
}
/**
* Copy the property values of the given source bean into the given target bean.
* Note: The source and target classes do not have to match or even be derived
* from each other, as long as the properties match. Any bean properties that the
* source bean exposes but the target bean does not will silently be ignored.
* As of Spring Framework 5.3, this method honors generic type information
* when matching properties in the source and target objects. See the
* documentation for {@link #copyProperties(Object, Object)} for details.
* @param source the source bean
* @param target the target bean
* @param editable the class (or interface) to restrict property setting to
* @param ignoreProperties array of property names to ignore
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
private static void copyProperties(Object source, Object target, @Nullable Class> editable,
@Nullable String... ignoreProperties) throws BeansException {
Assert.notNull(source, "Source must not be null");
Assert.notNull(target, "Target must not be null");
Class> actualEditable = target.getClass();
if (editable != null) {
if (!editable.isInstance(target)) {
throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
"] not assignable to editable class [" + editable.getName() + "]");
}
actualEditable = editable;
}
PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);
Set
*
* @param source the source bean
* @param target the target bean
* @throws BeansException if the copying failed
* @see BeanWrapper
*/
public static void copyProperties(Object source, Object target) throws BeansException {
copyProperties(source, target, null, (String[]) null);
}
/**
* Copy the property values of the given source bean into the given target bean,
* only setting properties defined in the given "editable" class (or interface).
*
* source property type target property type copy supported
* {@code Integer} {@code Integer} yes
* {@code Integer} {@code Number} yes
* {@code List {@code List yes
* {@code List>} {@code List>} yes
* {@code List {@code List>} yes
* {@code List {@code List extends Number>} yes
* {@code String} {@code Integer} no
* {@code Number} {@code Integer} no
* {@code List {@code List no
* {@code List {@code List no