/*
* Copyright 2002-2010 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 org.springframework.beans;
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.net.URI;
import java.net.URL;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.WeakHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.MethodParameter;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
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.
*
* <p>Mainly for use within the framework, but to some degree also
* useful for application classes.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Rob Harrop
* @author Sam Brannen
*/
public abstract class BeanUtils {
private static final Log logger = LogFactory.getLog(BeanUtils.class);
private static final Map<Class<?>, Boolean> unknownEditorTypes =
Collections.synchronizedMap(new WeakHashMap<Class<?>, Boolean>());
/**
* Convenience method to instantiate a class using its no-arg constructor.
* As this method doesn't try to load classes by name, it should avoid
* class-loading issues.
* @param clazz class to instantiate
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated
*/
public static <T> T instantiate(Class<T> clazz) throws BeanInstantiationException {
Assert.notNull(clazz, "Class must not be null");
if (clazz.isInterface()) {
throw new BeanInstantiationException(clazz, "Specified class is an interface");
}
try {
return clazz.newInstance();
}
catch (InstantiationException ex) {
throw new BeanInstantiationException(clazz, "Is it an abstract class?", ex);
}
catch (IllegalAccessException ex) {
throw new BeanInstantiationException(clazz, "Is the constructor accessible?", ex);
}
}
/**
* Convenience method to instantiate a class using its no-arg constructor.
* As this method doesn't try to load classes by name, it should avoid
* class-loading issues.
* <p>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
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated
*/
public static <T> T instantiateClass(Class<T> clazz) throws BeanInstantiationException {
Assert.notNull(clazz, "Class must not be null");
if (clazz.isInterface()) {
throw new BeanInstantiationException(clazz, "Specified class is an interface");
}
try {
return instantiateClass(clazz.getDeclaredConstructor());
}
catch (NoSuchMethodException ex) {
throw new BeanInstantiationException(clazz, "No default constructor found", ex);
}
}
/**
* Convenience method to instantiate a class using the given constructor.
* As this method doesn't try to load classes by name, it should avoid
* class-loading issues.
* <p>Note that this method tries to set the constructor accessible
* if given a non-accessible (that is, non-public) constructor.
* @param ctor the constructor to instantiate
* @param args the constructor arguments to apply
* @return the new instance
* @throws BeanInstantiationException if the bean cannot be instantiated
*/
public static <T> T instantiateClass(Constructor<T> ctor, Object... args) throws BeanInstantiationException {
Assert.notNull(ctor, "Constructor must not be null");
try {
ReflectionUtils.makeAccessible(ctor);
return ctor.newInstance(args);
}
catch (InstantiationException ex) {
throw new BeanInstantiationException(ctor.getDeclaringClass(),
"Is it an abstract class?", ex);
}
catch (IllegalAccessException ex) {
throw new BeanInstantiationException(ctor.getDeclaringClass(),
"Is the constructor accessible?", ex);
}
catch (IllegalArgumentException ex) {
throw new BeanInstantiationException(ctor.getDeclaringClass(),
"Illegal arguments for constructor", ex);
}
catch (InvocationTargetException ex) {
throw new BeanInstantiationException(ctor.getDeclaringClass(),
"Constructor threw exception", ex.getTargetException());
}
}
/**
* Find a method with the given method name and the given parameter types,
* declared on the given class or one of its superclasses. Prefers public methods,
* but will return a protected, package access, or private method too.
* <p>Checks <code>Class.getMethod</code> first, falling back to
* <code>findDeclaredMethod</code>. 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</code> if not found
* @see java.lang.Class#getMethod
* @see #findDeclaredMethod
*/
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.
* <p>Checks <code>Class.getDeclaredMethod</code>, 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</code> if not found
* @see java.lang.Class#getDeclaredMethod
*/
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.
* <p>Checks <code>Class.getMethods</code> first, falling back to
* <code>findDeclaredMethodWithMinimalParameters</code>. 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</code> 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 java.lang.Class#getMethods
* @see #findDeclaredMethodWithMinimalParameters
*/
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.
* <p>Checks <code>Class.getDeclaredMethods</code>, 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</code> 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 java.lang.Class#getDeclaredMethods
*/
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</code> 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
*/
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.getParameterTypes().length;
if (targetMethod == null || numParams < targetMethod.getParameterTypes().length) {
targetMethod = method;
numMethodsFoundWithCurrentMinimumArgs = 1;
}
else {
if (targetMethod.getParameterTypes().length == numParams) {
// 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])]</code>,
* where <code>arg_list</code> is an optional, comma-separated list of fully-qualified
* type names, and attempts to resolve that signature against the supplied <code>Class</code>.
* <p>When not supplying an argument list (<code>methodName</code>) 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.
* <p>Note then that <code>methodName</code> and <code>methodName()</code> are <strong>not</strong>
* resolved in the same way. The signature <code>methodName</code> means the method called
* <code>methodName</code> with the least number of arguments, whereas <code>methodName()</code>
* means the method called <code>methodName</code> with exactly 0 arguments.
* <p>If no method can be found, then <code>null</code> 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
*/
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 firstParen = signature.indexOf("(");
int lastParen = signature.indexOf(")");
if (firstParen > -1 && lastParen == -1) {
throw new IllegalArgumentException("Invalid method signature '" + signature +
"': expected closing ')' for args list");
}
else if (lastParen > -1 && firstParen == -1) {
throw new IllegalArgumentException("Invalid method signature '" + signature +
"': expected opening '(' for args list");
}
else if (firstParen == -1 && lastParen == -1) {
return findMethodWithMinimalParameters(clazz, signature);
}
else {
String methodName = signature.substring(0, firstParen);
String[] parameterTypeNames =
StringUtils.commaDelimitedListToStringArray(signature.substring(firstParen + 1, lastParen));
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</code>s of a given class.
* @param clazz the Class to retrieve the PropertyDescriptors for
* @return an array of <code>PropertyDescriptors</code> for the given class
* @throws BeansException if PropertyDescriptor look fails
*/
public static PropertyDescriptor[] getPropertyDescriptors(Class<?> clazz) throws BeansException {
CachedIntrospectionResults cr = CachedIntrospectionResults.forClass(clazz);
return cr.getPropertyDescriptors();
}
/**
* Retrieve the JavaBeans <code>PropertyDescriptors</code> 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</code> if none
* @throws BeansException if PropertyDescriptor lookup fails
*/
public static PropertyDescriptor getPropertyDescriptor(Class<?> clazz, String propertyName)
throws BeansException {
CachedIntrospectionResults cr = CachedIntrospectionResults.forClass(clazz);
return cr.getPropertyDescriptor(propertyName);
}
/**
* Find a JavaBeans <code>PropertyDescriptor</code> 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
* @return the corresponding PropertyDescriptor, or <code>null</code> if none
* @throws BeansException if PropertyDescriptor lookup fails
*/
public static PropertyDescriptor findPropertyForMethod(Method method) throws BeansException {
Assert.notNull(method, "Method must not be null");
PropertyDescriptor[] pds = getPropertyDescriptors(method.getDeclaringClass());
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").
* <p>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</code> if none found
*/
public static PropertyEditor findEditorByConvention(Class<?> targetType) {
if (targetType == null || targetType.isArray() || unknownEditorTypes.containsKey(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
if (logger.isDebugEnabled()) {
logger.debug("Could not access system ClassLoader: " + ex);
}
return null;
}
}
String editorName = targetType.getName() + "Editor";
try {
Class<?> editorClass = cl.loadClass(editorName);
if (!PropertyEditor.class.isAssignableFrom(editorClass)) {
if (logger.isWarnEnabled()) {
logger.warn("Editor class [" + editorName +
"] does not implement [java.beans.PropertyEditor] interface");
}
unknownEditorTypes.put(targetType, Boolean.TRUE);
return null;
}
return (PropertyEditor) instantiateClass(editorClass);
}
catch (ClassNotFoundException ex) {
if (logger.isDebugEnabled()) {
logger.debug("No property editor [" + editorName + "] found for type " +
targetType.getName() + " according to 'Editor' suffix convention");
}
unknownEditorTypes.put(targetType, Boolean.TRUE);
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</code> as fallback
*/
public static Class<?> findPropertyType(String propertyName, Class<?>[] beanClasses) {
if (beanClasses != null) {
for (Class<?> beanClass : beanClasses) {
PropertyDescriptor pd = getPropertyDescriptor(beanClass, propertyName);
if (pd != null) {
return pd.getPropertyType();
}
}
}
return Object.class;
}
/**
* 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) {
return new MethodParameter(
((GenericTypeAwarePropertyDescriptor) pd).getWriteMethodParameter());
}
else {
return new MethodParameter(pd.getWriteMethod(), 0);
}
}
/**
* Check if the given type represents a "simple" property:
* a primitive, a String or other CharSequence, a Number, a Date,
* a URI, a URL, a Locale, a Class, or a corresponding array.
* <p>Used to determine properties to check for a "simple" dependency-check.
* @param clazz 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
*/
public static boolean isSimpleProperty(Class<?> clazz) {
Assert.notNull(clazz, "Class must not be null");
return isSimpleValueType(clazz) || (clazz.isArray() && isSimpleValueType(clazz.getComponentType()));
}
/**
* Check if the given type represents a "simple" value type:
* a primitive, a String or other CharSequence, a Number, a Date,
* a URI, a URL, a Locale or a Class.
* @param clazz the type to check
* @return whether the given type represents a "simple" value type
*/
public static boolean isSimpleValueType(Class<?> clazz) {
return ClassUtils.isPrimitiveOrWrapper(clazz) || clazz.isEnum() ||
CharSequence.class.isAssignableFrom(clazz) ||
Number.class.isAssignableFrom(clazz) ||
Date.class.isAssignableFrom(clazz) ||
clazz.equals(URI.class) || clazz.equals(URL.class) ||
clazz.equals(Locale.class) || clazz.equals(Class.class);
}
/**
* Copy the property values of the given source bean into the target bean.
* <p>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.
* <p>This is just a convenience method. For more complex transfer needs,
* consider using a full BeanWrapper.
* @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, 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).
* <p>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.
* <p>This is just a convenience method. For more complex transfer needs,
* consider using a full BeanWrapper.
* @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, null);
}
/**
* Copy the property values of the given source bean into the given target bean,
* ignoring the given "ignoreProperties".
* <p>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.
* <p>This is just a convenience method. For more complex transfer needs,
* consider using a full BeanWrapper.
* @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.
* <p>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.
* @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, Class<?> editable, 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);
List<String> ignoreList = (ignoreProperties != null) ? Arrays.asList(ignoreProperties) : null;
for (PropertyDescriptor targetPd : targetPds) {
if (targetPd.getWriteMethod() != null &&
(ignoreProperties == null || (!ignoreList.contains(targetPd.getName())))) {
PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
if (sourcePd != null && sourcePd.getReadMethod() != null) {
try {
Method readMethod = sourcePd.getReadMethod();
if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
readMethod.setAccessible(true);
}
Object value = readMethod.invoke(source);
Method writeMethod = targetPd.getWriteMethod();
if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
writeMethod.setAccessible(true);
}
writeMethod.invoke(target, value);
}
catch (Throwable ex) {
throw new FatalBeanException("Could not copy properties from source to target", ex);
}
}
}
}
}
}
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