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/*
* Copyright 2002-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.util;
import java.beans.Introspector;
import java.io.Closeable;
import java.io.Externalizable;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.StringJoiner;
import org.springframework.lang.Nullable;
/**
* Miscellaneous {@code java.lang.Class} utility methods.
* Mainly for internal use within the framework.
*
* @author Juergen Hoeller
* @author Keith Donald
* @author Rob Harrop
* @author Sam Brannen
* @since 1.1
* @see TypeUtils
* @see ReflectionUtils
*/
public abstract class ClassUtils {
/** Suffix for array class names: {@code "[]"}. */
public static final String ARRAY_SUFFIX = "[]";
/** Prefix for internal array class names: {@code "["}. */
private static final String INTERNAL_ARRAY_PREFIX = "[";
/** Prefix for internal non-primitive array class names: {@code "[L"}. */
private static final String NON_PRIMITIVE_ARRAY_PREFIX = "[L";
/** A reusable empty class array constant. */
private static final Class[] EMPTY_CLASS_ARRAY = {};
/** The package separator character: {@code '.'}. */
private static final char PACKAGE_SEPARATOR = '.';
/** The path separator character: {@code '/'}. */
private static final char PATH_SEPARATOR = '/';
/** The nested class separator character: {@code '$'}. */
private static final char NESTED_CLASS_SEPARATOR = '$';
/** The CGLIB class separator: {@code "$$"}. */
public static final String CGLIB_CLASS_SEPARATOR = "$$";
/** The ".class" file suffix. */
public static final String CLASS_FILE_SUFFIX = ".class";
/**
* Map with primitive wrapper type as key and corresponding primitive
* type as value, for example: Integer.class -> int.class.
*/
private static final Map, Class> primitiveWrapperTypeMap = new IdentityHashMap<>(9);
/**
* Map with primitive type as key and corresponding wrapper
* type as value, for example: int.class -> Integer.class.
*/
private static final Map, Class> primitiveTypeToWrapperMap = new IdentityHashMap<>(9);
/**
* Map with primitive type name as key and corresponding primitive
* type as value, for example: "int" -> "int.class".
*/
private static final Map> primitiveTypeNameMap = new HashMap<>(32);
/**
* Map with common Java language class name as key and corresponding Class as value.
* Primarily for efficient deserialization of remote invocations.
*/
private static final Map> commonClassCache = new HashMap<>(64);
/**
* Common Java language interfaces which are supposed to be ignored
* when searching for 'primary' user-level interfaces.
*/
private static final Set> javaLanguageInterfaces;
/**
* Cache for equivalent methods on an interface implemented by the declaring class.
*/
private static final Map interfaceMethodCache = new ConcurrentReferenceHashMap<>(256);
static {
primitiveWrapperTypeMap.put(Boolean.class, boolean.class);
primitiveWrapperTypeMap.put(Byte.class, byte.class);
primitiveWrapperTypeMap.put(Character.class, char.class);
primitiveWrapperTypeMap.put(Double.class, double.class);
primitiveWrapperTypeMap.put(Float.class, float.class);
primitiveWrapperTypeMap.put(Integer.class, int.class);
primitiveWrapperTypeMap.put(Long.class, long.class);
primitiveWrapperTypeMap.put(Short.class, short.class);
primitiveWrapperTypeMap.put(Void.class, void.class);
// Map entry iteration is less expensive to initialize than forEach with lambdas
for (Map.Entry, Class> entry : primitiveWrapperTypeMap.entrySet()) {
primitiveTypeToWrapperMap.put(entry.getValue(), entry.getKey());
registerCommonClasses(entry.getKey());
}
Set> primitiveTypes = new HashSet<>(32);
primitiveTypes.addAll(primitiveWrapperTypeMap.values());
Collections.addAll(primitiveTypes, boolean[].class, byte[].class, char[].class,
double[].class, float[].class, int[].class, long[].class, short[].class);
for (Class primitiveType : primitiveTypes) {
primitiveTypeNameMap.put(primitiveType.getName(), primitiveType);
}
registerCommonClasses(Boolean[].class, Byte[].class, Character[].class, Double[].class,
Float[].class, Integer[].class, Long[].class, Short[].class);
registerCommonClasses(Number.class, Number[].class, String.class, String[].class,
Class.class, Class[].class, Object.class, Object[].class);
registerCommonClasses(Throwable.class, Exception.class, RuntimeException.class,
Error.class, StackTraceElement.class, StackTraceElement[].class);
registerCommonClasses(Enum.class, Iterable.class, Iterator.class, Enumeration.class,
Collection.class, List.class, Set.class, Map.class, Map.Entry.class, Optional.class);
Class[] javaLanguageInterfaceArray = {Serializable.class, Externalizable.class,
Closeable.class, AutoCloseable.class, Cloneable.class, Comparable.class};
registerCommonClasses(javaLanguageInterfaceArray);
javaLanguageInterfaces = new HashSet<>(Arrays.asList(javaLanguageInterfaceArray));
}
/**
* Register the given common classes with the ClassUtils cache.
*/
private static void registerCommonClasses(Class... commonClasses) {
for (Class clazz : commonClasses) {
commonClassCache.put(clazz.getName(), clazz);
}
}
/**
* Return the default ClassLoader to use: typically the thread context
* ClassLoader, if available; the ClassLoader that loaded the ClassUtils
* class will be used as fallback.
* Call this method if you intend to use the thread context ClassLoader
* in a scenario where you clearly prefer a non-null ClassLoader reference:
* for example, for class path resource loading (but not necessarily for
* {@code Class.forName}, which accepts a {@code null} ClassLoader
* reference as well).
* @return the default ClassLoader (only {@code null} if even the system
* ClassLoader isn't accessible)
* @see Thread#getContextClassLoader()
* @see ClassLoader#getSystemClassLoader()
*/
@Nullable
public static ClassLoader getDefaultClassLoader() {
ClassLoader cl = null;
try {
cl = Thread.currentThread().getContextClassLoader();
}
catch (Throwable ex) {
// Cannot access thread context ClassLoader - falling back...
}
if (cl == null) {
// No thread context class loader -> use class loader of this class.
cl = ClassUtils.class.getClassLoader();
if (cl == null) {
// getClassLoader() returning null indicates the bootstrap ClassLoader
try {
cl = ClassLoader.getSystemClassLoader();
}
catch (Throwable ex) {
// Cannot access system ClassLoader - oh well, maybe the caller can live with null...
}
}
}
return cl;
}
/**
* Override the thread context ClassLoader with the environment's bean ClassLoader
* if necessary, i.e. if the bean ClassLoader is not equivalent to the thread
* context ClassLoader already.
* @param classLoaderToUse the actual ClassLoader to use for the thread context
* @return the original thread context ClassLoader, or {@code null} if not overridden
*/
@Nullable
public static ClassLoader overrideThreadContextClassLoader(@Nullable ClassLoader classLoaderToUse) {
Thread currentThread = Thread.currentThread();
ClassLoader threadContextClassLoader = currentThread.getContextClassLoader();
if (classLoaderToUse != null && !classLoaderToUse.equals(threadContextClassLoader)) {
currentThread.setContextClassLoader(classLoaderToUse);
return threadContextClassLoader;
}
else {
return null;
}
}
/**
* Replacement for {@code Class.forName()} that also returns Class instances
* for primitives (e.g. "int") and array class names (e.g. "String[]").
* Furthermore, it is also capable of resolving nested class names in Java source
* style (e.g. "java.lang.Thread.State" instead of "java.lang.Thread$State").
* @param name the name of the Class
* @param classLoader the class loader to use
* (may be {@code null}, which indicates the default class loader)
* @return a class instance for the supplied name
* @throws ClassNotFoundException if the class was not found
* @throws LinkageError if the class file could not be loaded
* @see Class#forName(String, boolean, ClassLoader)
*/
public static Class forName(String name, @Nullable ClassLoader classLoader)
throws ClassNotFoundException, LinkageError {
Assert.notNull(name, "Name must not be null");
Class clazz = resolvePrimitiveClassName(name);
if (clazz == null) {
clazz = commonClassCache.get(name);
}
if (clazz != null) {
return clazz;
}
// "java.lang.String[]" style arrays
if (name.endsWith(ARRAY_SUFFIX)) {
String elementClassName = name.substring(0, name.length() - ARRAY_SUFFIX.length());
Class elementClass = forName(elementClassName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
// "[Ljava.lang.String;" style arrays
if (name.startsWith(NON_PRIMITIVE_ARRAY_PREFIX) && name.endsWith(";")) {
String elementName = name.substring(NON_PRIMITIVE_ARRAY_PREFIX.length(), name.length() - 1);
Class elementClass = forName(elementName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
// "[[I" or "[[Ljava.lang.String;" style arrays
if (name.startsWith(INTERNAL_ARRAY_PREFIX)) {
String elementName = name.substring(INTERNAL_ARRAY_PREFIX.length());
Class elementClass = forName(elementName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
ClassLoader clToUse = classLoader;
if (clToUse == null) {
clToUse = getDefaultClassLoader();
}
try {
return Class.forName(name, false, clToUse);
}
catch (ClassNotFoundException ex) {
int lastDotIndex = name.lastIndexOf(PACKAGE_SEPARATOR);
if (lastDotIndex != -1) {
String nestedClassName =
name.substring(0, lastDotIndex) + NESTED_CLASS_SEPARATOR + name.substring(lastDotIndex + 1);
try {
return Class.forName(nestedClassName, false, clToUse);
}
catch (ClassNotFoundException ex2) {
// Swallow - let original exception get through
}
}
throw ex;
}
}
/**
* Resolve the given class name into a Class instance. Supports
* primitives (like "int") and array class names (like "String[]").
*
This is effectively equivalent to the {@code forName}
* method with the same arguments, with the only difference being
* the exceptions thrown in case of class loading failure.
* @param className the name of the Class
* @param classLoader the class loader to use
* (may be {@code null}, which indicates the default class loader)
* @return a class instance for the supplied name
* @throws IllegalArgumentException if the class name was not resolvable
* (that is, the class could not be found or the class file could not be loaded)
* @throws IllegalStateException if the corresponding class is resolvable but
* there was a readability mismatch in the inheritance hierarchy of the class
* (typically a missing dependency declaration in a Jigsaw module definition
* for a superclass or interface implemented by the class to be loaded here)
* @see #forName(String, ClassLoader)
*/
public static Class resolveClassName(String className, @Nullable ClassLoader classLoader)
throws IllegalArgumentException {
try {
return forName(className, classLoader);
}
catch (IllegalAccessError err) {
throw new IllegalStateException("Readability mismatch in inheritance hierarchy of class [" +
className + "]: " + err.getMessage(), err);
}
catch (LinkageError err) {
throw new IllegalArgumentException("Unresolvable class definition for class [" + className + "]", err);
}
catch (ClassNotFoundException ex) {
throw new IllegalArgumentException("Could not find class [" + className + "]", ex);
}
}
/**
* Determine whether the {@link Class} identified by the supplied name is present
* and can be loaded. Will return {@code false} if either the class or
* one of its dependencies is not present or cannot be loaded.
* @param className the name of the class to check
* @param classLoader the class loader to use
* (may be {@code null} which indicates the default class loader)
* @return whether the specified class is present (including all of its
* superclasses and interfaces)
* @throws IllegalStateException if the corresponding class is resolvable but
* there was a readability mismatch in the inheritance hierarchy of the class
* (typically a missing dependency declaration in a Jigsaw module definition
* for a superclass or interface implemented by the class to be checked here)
*/
public static boolean isPresent(String className, @Nullable ClassLoader classLoader) {
try {
forName(className, classLoader);
return true;
}
catch (IllegalAccessError err) {
throw new IllegalStateException("Readability mismatch in inheritance hierarchy of class [" +
className + "]: " + err.getMessage(), err);
}
catch (Throwable ex) {
// Typically ClassNotFoundException or NoClassDefFoundError...
return false;
}
}
/**
* Check whether the given class is visible in the given ClassLoader.
* @param clazz the class to check (typically an interface)
* @param classLoader the ClassLoader to check against
* (may be {@code null} in which case this method will always return {@code true})
*/
public static boolean isVisible(Class clazz, @Nullable ClassLoader classLoader) {
if (classLoader == null) {
return true;
}
try {
if (clazz.getClassLoader() == classLoader) {
return true;
}
}
catch (SecurityException ex) {
// Fall through to loadable check below
}
// Visible if same Class can be loaded from given ClassLoader
return isLoadable(clazz, classLoader);
}
/**
* Check whether the given class is cache-safe in the given context,
* i.e. whether it is loaded by the given ClassLoader or a parent of it.
* @param clazz the class to analyze
* @param classLoader the ClassLoader to potentially cache metadata in
* (may be {@code null} which indicates the system class loader)
*/
public static boolean isCacheSafe(Class clazz, @Nullable ClassLoader classLoader) {
Assert.notNull(clazz, "Class must not be null");
try {
ClassLoader target = clazz.getClassLoader();
// Common cases
if (target == classLoader || target == null) {
return true;
}
if (classLoader == null) {
return false;
}
// Check for match in ancestors -> positive
ClassLoader current = classLoader;
while (current != null) {
current = current.getParent();
if (current == target) {
return true;
}
}
// Check for match in children -> negative
while (target != null) {
target = target.getParent();
if (target == classLoader) {
return false;
}
}
}
catch (SecurityException ex) {
// Fall through to loadable check below
}
// Fallback for ClassLoaders without parent/child relationship:
// safe if same Class can be loaded from given ClassLoader
return (classLoader != null && isLoadable(clazz, classLoader));
}
/**
* Check whether the given class is loadable in the given ClassLoader.
* @param clazz the class to check (typically an interface)
* @param classLoader the ClassLoader to check against
* @since 5.0.6
*/
private static boolean isLoadable(Class clazz, ClassLoader classLoader) {
try {
return (clazz == classLoader.loadClass(clazz.getName()));
// Else: different class with same name found
}
catch (ClassNotFoundException ex) {
// No corresponding class found at all
return false;
}
}
/**
* Resolve the given class name as primitive class, if appropriate,
* according to the JVM's naming rules for primitive classes.
*
Also supports the JVM's internal class names for primitive arrays.
* Does not support the "[]" suffix notation for primitive arrays;
* this is only supported by {@link #forName(String, ClassLoader)}.
* @param name the name of the potentially primitive class
* @return the primitive class, or {@code null} if the name does not denote
* a primitive class or primitive array class
*/
@Nullable
public static Class resolvePrimitiveClassName(@Nullable String name) {
Class result = null;
// Most class names will be quite long, considering that they
// SHOULD sit in a package, so a length check is worthwhile.
if (name != null && name.length() <= 7) {
// Could be a primitive - likely.
result = primitiveTypeNameMap.get(name);
}
return result;
}
/**
* Check if the given class represents a primitive wrapper,
* i.e. Boolean, Byte, Character, Short, Integer, Long, Float, Double, or
* Void.
* @param clazz the class to check
* @return whether the given class is a primitive wrapper class
*/
public static boolean isPrimitiveWrapper(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return primitiveWrapperTypeMap.containsKey(clazz);
}
/**
* Check if the given class represents a primitive (i.e. boolean, byte,
* char, short, int, long, float, or double), {@code void}, or a wrapper for
* those types (i.e. Boolean, Byte, Character, Short, Integer, Long, Float,
* Double, or Void).
* @param clazz the class to check
* @return {@code true} if the given class represents a primitive, void, or
* a wrapper class
*/
public static boolean isPrimitiveOrWrapper(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return (clazz.isPrimitive() || isPrimitiveWrapper(clazz));
}
/**
* Check if the given class represents an array of primitives,
* i.e. boolean, byte, char, short, int, long, float, or double.
* @param clazz the class to check
* @return whether the given class is a primitive array class
*/
public static boolean isPrimitiveArray(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return (clazz.isArray() && clazz.getComponentType().isPrimitive());
}
/**
* Check if the given class represents an array of primitive wrappers,
* i.e. Boolean, Byte, Character, Short, Integer, Long, Float, or Double.
* @param clazz the class to check
* @return whether the given class is a primitive wrapper array class
*/
public static boolean isPrimitiveWrapperArray(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return (clazz.isArray() && isPrimitiveWrapper(clazz.getComponentType()));
}
/**
* Resolve the given class if it is a primitive class,
* returning the corresponding primitive wrapper type instead.
* @param clazz the class to check
* @return the original class, or a primitive wrapper for the original primitive type
*/
public static Class resolvePrimitiveIfNecessary(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return (clazz.isPrimitive() && clazz != void.class ? primitiveTypeToWrapperMap.get(clazz) : clazz);
}
/**
* Check if the right-hand side type may be assigned to the left-hand side
* type, assuming setting by reflection. Considers primitive wrapper
* classes as assignable to the corresponding primitive types.
* @param lhsType the target type
* @param rhsType the value type that should be assigned to the target type
* @return if the target type is assignable from the value type
* @see TypeUtils#isAssignable(java.lang.reflect.Type, java.lang.reflect.Type)
*/
public static boolean isAssignable(Class lhsType, Class rhsType) {
Assert.notNull(lhsType, "Left-hand side type must not be null");
Assert.notNull(rhsType, "Right-hand side type must not be null");
if (lhsType.isAssignableFrom(rhsType)) {
return true;
}
if (lhsType.isPrimitive()) {
Class resolvedPrimitive = primitiveWrapperTypeMap.get(rhsType);
return (lhsType == resolvedPrimitive);
}
else {
Class resolvedWrapper = primitiveTypeToWrapperMap.get(rhsType);
return (resolvedWrapper != null && lhsType.isAssignableFrom(resolvedWrapper));
}
}
/**
* Determine if the given type is assignable from the given value,
* assuming setting by reflection. Considers primitive wrapper classes
* as assignable to the corresponding primitive types.
* @param type the target type
* @param value the value that should be assigned to the type
* @return if the type is assignable from the value
*/
public static boolean isAssignableValue(Class type, @Nullable Object value) {
Assert.notNull(type, "Type must not be null");
return (value != null ? isAssignable(type, value.getClass()) : !type.isPrimitive());
}
/**
* Convert a "/"-based resource path to a "."-based fully qualified class name.
* @param resourcePath the resource path pointing to a class
* @return the corresponding fully qualified class name
*/
public static String convertResourcePathToClassName(String resourcePath) {
Assert.notNull(resourcePath, "Resource path must not be null");
return resourcePath.replace(PATH_SEPARATOR, PACKAGE_SEPARATOR);
}
/**
* Convert a "."-based fully qualified class name to a "/"-based resource path.
* @param className the fully qualified class name
* @return the corresponding resource path, pointing to the class
*/
public static String convertClassNameToResourcePath(String className) {
Assert.notNull(className, "Class name must not be null");
return className.replace(PACKAGE_SEPARATOR, PATH_SEPARATOR);
}
/**
* Return a path suitable for use with {@code ClassLoader.getResource}
* (also suitable for use with {@code Class.getResource} by prepending a
* slash ('/') to the return value). Built by taking the package of the specified
* class file, converting all dots ('.') to slashes ('/'), adding a trailing slash
* if necessary, and concatenating the specified resource name to this.
*
As such, this function may be used to build a path suitable for
* loading a resource file that is in the same package as a class file,
* although {@link org.springframework.core.io.ClassPathResource} is usually
* even more convenient.
* @param clazz the Class whose package will be used as the base
* @param resourceName the resource name to append. A leading slash is optional.
* @return the built-up resource path
* @see ClassLoader#getResource
* @see Class#getResource
*/
public static String addResourcePathToPackagePath(Class clazz, String resourceName) {
Assert.notNull(resourceName, "Resource name must not be null");
if (!resourceName.startsWith("/")) {
return classPackageAsResourcePath(clazz) + '/' + resourceName;
}
return classPackageAsResourcePath(clazz) + resourceName;
}
/**
* Given an input class object, return a string which consists of the
* class's package name as a pathname, i.e., all dots ('.') are replaced by
* slashes ('/'). Neither a leading nor trailing slash is added. The result
* could be concatenated with a slash and the name of a resource and fed
* directly to {@code ClassLoader.getResource()}. For it to be fed to
* {@code Class.getResource} instead, a leading slash would also have
* to be prepended to the returned value.
* @param clazz the input class. A {@code null} value or the default
* (empty) package will result in an empty string ("") being returned.
* @return a path which represents the package name
* @see ClassLoader#getResource
* @see Class#getResource
*/
public static String classPackageAsResourcePath(@Nullable Class clazz) {
if (clazz == null) {
return "";
}
String className = clazz.getName();
int packageEndIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
if (packageEndIndex == -1) {
return "";
}
String packageName = className.substring(0, packageEndIndex);
return packageName.replace(PACKAGE_SEPARATOR, PATH_SEPARATOR);
}
/**
* Build a String that consists of the names of the classes/interfaces
* in the given array.
*
Basically like {@code AbstractCollection.toString()}, but stripping
* the "class "/"interface " prefix before every class name.
* @param classes an array of Class objects
* @return a String of form "[com.foo.Bar, com.foo.Baz]"
* @see java.util.AbstractCollection#toString()
*/
public static String classNamesToString(Class... classes) {
return classNamesToString(Arrays.asList(classes));
}
/**
* Build a String that consists of the names of the classes/interfaces
* in the given collection.
*
Basically like {@code AbstractCollection.toString()}, but stripping
* the "class "/"interface " prefix before every class name.
* @param classes a Collection of Class objects (may be {@code null})
* @return a String of form "[com.foo.Bar, com.foo.Baz]"
* @see java.util.AbstractCollection#toString()
*/
public static String classNamesToString(@Nullable Collection> classes) {
if (CollectionUtils.isEmpty(classes)) {
return "[]";
}
StringJoiner stringJoiner = new StringJoiner(", ", "[", "]");
for (Class clazz : classes) {
stringJoiner.add(clazz.getName());
}
return stringJoiner.toString();
}
/**
* Copy the given {@code Collection} into a {@code Class} array.
* The {@code Collection} must contain {@code Class} elements only.
* @param collection the {@code Collection} to copy
* @return the {@code Class} array
* @since 3.1
* @see StringUtils#toStringArray
*/
public static Class[] toClassArray(@Nullable Collection> collection) {
return (!CollectionUtils.isEmpty(collection) ? collection.toArray(EMPTY_CLASS_ARRAY) : EMPTY_CLASS_ARRAY);
}
/**
* Return all interfaces that the given instance implements as an array,
* including ones implemented by superclasses.
* @param instance the instance to analyze for interfaces
* @return all interfaces that the given instance implements as an array
*/
public static Class[] getAllInterfaces(Object instance) {
Assert.notNull(instance, "Instance must not be null");
return getAllInterfacesForClass(instance.getClass());
}
/**
* Return all interfaces that the given class implements as an array,
* including ones implemented by superclasses.
* If the class itself is an interface, it gets returned as sole interface.
* @param clazz the class to analyze for interfaces
* @return all interfaces that the given object implements as an array
*/
public static Class[] getAllInterfacesForClass(Class clazz) {
return getAllInterfacesForClass(clazz, null);
}
/**
* Return all interfaces that the given class implements as an array,
* including ones implemented by superclasses.
*
If the class itself is an interface, it gets returned as sole interface.
* @param clazz the class to analyze for interfaces
* @param classLoader the ClassLoader that the interfaces need to be visible in
* (may be {@code null} when accepting all declared interfaces)
* @return all interfaces that the given object implements as an array
*/
public static Class[] getAllInterfacesForClass(Class clazz, @Nullable ClassLoader classLoader) {
return toClassArray(getAllInterfacesForClassAsSet(clazz, classLoader));
}
/**
* Return all interfaces that the given instance implements as a Set,
* including ones implemented by superclasses.
* @param instance the instance to analyze for interfaces
* @return all interfaces that the given instance implements as a Set
*/
public static Set> getAllInterfacesAsSet(Object instance) {
Assert.notNull(instance, "Instance must not be null");
return getAllInterfacesForClassAsSet(instance.getClass());
}
/**
* Return all interfaces that the given class implements as a Set,
* including ones implemented by superclasses.
* If the class itself is an interface, it gets returned as sole interface.
* @param clazz the class to analyze for interfaces
* @return all interfaces that the given object implements as a Set
*/
public static Set> getAllInterfacesForClassAsSet(Class clazz) {
return getAllInterfacesForClassAsSet(clazz, null);
}
/**
* Return all interfaces that the given class implements as a Set,
* including ones implemented by superclasses.
* If the class itself is an interface, it gets returned as sole interface.
* @param clazz the class to analyze for interfaces
* @param classLoader the ClassLoader that the interfaces need to be visible in
* (may be {@code null} when accepting all declared interfaces)
* @return all interfaces that the given object implements as a Set
*/
public static Set> getAllInterfacesForClassAsSet(Class clazz, @Nullable ClassLoader classLoader) {
Assert.notNull(clazz, "Class must not be null");
if (clazz.isInterface() && isVisible(clazz, classLoader)) {
return Collections.singleton(clazz);
}
Set> interfaces = new LinkedHashSet<>();
Class current = clazz;
while (current != null) {
Class[] ifcs = current.getInterfaces();
for (Class ifc : ifcs) {
if (isVisible(ifc, classLoader)) {
interfaces.add(ifc);
}
}
current = current.getSuperclass();
}
return interfaces;
}
/**
* Create a composite interface Class for the given interfaces,
* implementing the given interfaces in one single Class.
* This implementation builds a JDK proxy class for the given interfaces.
* @param interfaces the interfaces to merge
* @param classLoader the ClassLoader to create the composite Class in
* @return the merged interface as Class
* @throws IllegalArgumentException if the specified interfaces expose
* conflicting method signatures (or a similar constraint is violated)
* @see java.lang.reflect.Proxy#getProxyClass
*/
@SuppressWarnings("deprecation") // on JDK 9
public static Class createCompositeInterface(Class[] interfaces, @Nullable ClassLoader classLoader) {
Assert.notEmpty(interfaces, "Interface array must not be empty");
return Proxy.getProxyClass(classLoader, interfaces);
}
/**
* Determine the common ancestor of the given classes, if any.
* @param clazz1 the class to introspect
* @param clazz2 the other class to introspect
* @return the common ancestor (i.e. common superclass, one interface
* extending the other), or {@code null} if none found. If any of the
* given classes is {@code null}, the other class will be returned.
* @since 3.2.6
*/
@Nullable
public static Class determineCommonAncestor(@Nullable Class clazz1, @Nullable Class clazz2) {
if (clazz1 == null) {
return clazz2;
}
if (clazz2 == null) {
return clazz1;
}
if (clazz1.isAssignableFrom(clazz2)) {
return clazz1;
}
if (clazz2.isAssignableFrom(clazz1)) {
return clazz2;
}
Class ancestor = clazz1;
do {
ancestor = ancestor.getSuperclass();
if (ancestor == null || Object.class == ancestor) {
return null;
}
}
while (!ancestor.isAssignableFrom(clazz2));
return ancestor;
}
/**
* Determine whether the given interface is a common Java language interface:
* {@link Serializable}, {@link Externalizable}, {@link Closeable}, {@link AutoCloseable},
* {@link Cloneable}, {@link Comparable} - all of which can be ignored when looking
* for 'primary' user-level interfaces. Common characteristics: no service-level
* operations, no bean property methods, no default methods.
* @param ifc the interface to check
* @since 5.0.3
*/
public static boolean isJavaLanguageInterface(Class ifc) {
return javaLanguageInterfaces.contains(ifc);
}
/**
* Determine if the supplied class is an inner class,
* i.e. a non-static member of an enclosing class.
* @return {@code true} if the supplied class is an inner class
* @since 5.0.5
* @see Class#isMemberClass()
*/
public static boolean isInnerClass(Class clazz) {
return (clazz.isMemberClass() && !Modifier.isStatic(clazz.getModifiers()));
}
/**
* Determine if the supplied {@link Class} is a JVM-generated implementation
* class for a lambda expression or method reference.
*
This method makes a best-effort attempt at determining this, based on
* checks that work on modern, mainstream JVMs.
* @param clazz the class to check
* @return {@code true} if the class is a lambda implementation class
* @since 5.3.19
*/
public static boolean isLambdaClass(Class clazz) {
return (clazz.isSynthetic() && (clazz.getSuperclass() == Object.class) &&
(clazz.getInterfaces().length > 0) && clazz.getName().contains("$$Lambda"));
}
/**
* Check whether the given object is a CGLIB proxy.
* @param object the object to check
* @see #isCglibProxyClass(Class)
* @see org.springframework.aop.support.AopUtils#isCglibProxy(Object)
* @deprecated as of 5.2, in favor of custom (possibly narrower) checks
*/
@Deprecated
public static boolean isCglibProxy(Object object) {
return isCglibProxyClass(object.getClass());
}
/**
* Check whether the specified class is a CGLIB-generated class.
* @param clazz the class to check
* @see #isCglibProxyClassName(String)
* @deprecated as of 5.2, in favor of custom (possibly narrower) checks
*/
@Deprecated
public static boolean isCglibProxyClass(@Nullable Class clazz) {
return (clazz != null && isCglibProxyClassName(clazz.getName()));
}
/**
* Check whether the specified class name is a CGLIB-generated class.
* @param className the class name to check
* @deprecated as of 5.2, in favor of custom (possibly narrower) checks
*/
@Deprecated
public static boolean isCglibProxyClassName(@Nullable String className) {
return (className != null && className.contains(CGLIB_CLASS_SEPARATOR));
}
/**
* Return the user-defined class for the given instance: usually simply
* the class of the given instance, but the original class in case of a
* CGLIB-generated subclass.
* @param instance the instance to check
* @return the user-defined class
*/
public static Class getUserClass(Object instance) {
Assert.notNull(instance, "Instance must not be null");
return getUserClass(instance.getClass());
}
/**
* Return the user-defined class for the given class: usually simply the given
* class, but the original class in case of a CGLIB-generated subclass.
* @param clazz the class to check
* @return the user-defined class
*/
public static Class getUserClass(Class clazz) {
if (clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
Class superclass = clazz.getSuperclass();
if (superclass != null && superclass != Object.class) {
return superclass;
}
}
return clazz;
}
/**
* Return a descriptive name for the given object's type: usually simply
* the class name, but component type class name + "[]" for arrays,
* and an appended list of implemented interfaces for JDK proxies.
* @param value the value to introspect
* @return the qualified name of the class
*/
@Nullable
public static String getDescriptiveType(@Nullable Object value) {
if (value == null) {
return null;
}
Class clazz = value.getClass();
if (Proxy.isProxyClass(clazz)) {
String prefix = clazz.getName() + " implementing ";
StringJoiner result = new StringJoiner(",", prefix, "");
for (Class ifc : clazz.getInterfaces()) {
result.add(ifc.getName());
}
return result.toString();
}
else {
return clazz.getTypeName();
}
}
/**
* Check whether the given class matches the user-specified type name.
* @param clazz the class to check
* @param typeName the type name to match
*/
public static boolean matchesTypeName(Class clazz, @Nullable String typeName) {
return (typeName != null &&
(typeName.equals(clazz.getTypeName()) || typeName.equals(clazz.getSimpleName())));
}
/**
* Get the class name without the qualified package name.
* @param className the className to get the short name for
* @return the class name of the class without the package name
* @throws IllegalArgumentException if the className is empty
*/
public static String getShortName(String className) {
Assert.hasLength(className, "Class name must not be empty");
int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
int nameEndIndex = className.indexOf(CGLIB_CLASS_SEPARATOR);
if (nameEndIndex == -1) {
nameEndIndex = className.length();
}
String shortName = className.substring(lastDotIndex + 1, nameEndIndex);
shortName = shortName.replace(NESTED_CLASS_SEPARATOR, PACKAGE_SEPARATOR);
return shortName;
}
/**
* Get the class name without the qualified package name.
* @param clazz the class to get the short name for
* @return the class name of the class without the package name
*/
public static String getShortName(Class clazz) {
return getShortName(getQualifiedName(clazz));
}
/**
* Return the short string name of a Java class in uncapitalized JavaBeans
* property format. Strips the outer class name in case of a nested class.
* @param clazz the class
* @return the short name rendered in a standard JavaBeans property format
* @see java.beans.Introspector#decapitalize(String)
*/
public static String getShortNameAsProperty(Class clazz) {
String shortName = getShortName(clazz);
int dotIndex = shortName.lastIndexOf(PACKAGE_SEPARATOR);
shortName = (dotIndex != -1 ? shortName.substring(dotIndex + 1) : shortName);
return Introspector.decapitalize(shortName);
}
/**
* Determine the name of the class file, relative to the containing
* package: e.g. "String.class"
* @param clazz the class
* @return the file name of the ".class" file
*/
public static String getClassFileName(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
String className = clazz.getName();
int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR);
return className.substring(lastDotIndex + 1) + CLASS_FILE_SUFFIX;
}
/**
* Determine the name of the package of the given class,
* e.g. "java.lang" for the {@code java.lang.String} class.
* @param clazz the class
* @return the package name, or the empty String if the class
* is defined in the default package
*/
public static String getPackageName(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return getPackageName(clazz.getName());
}
/**
* Determine the name of the package of the given fully-qualified class name,
* e.g. "java.lang" for the {@code java.lang.String} class name.
* @param fqClassName the fully-qualified class name
* @return the package name, or the empty String if the class
* is defined in the default package
*/
public static String getPackageName(String fqClassName) {
Assert.notNull(fqClassName, "Class name must not be null");
int lastDotIndex = fqClassName.lastIndexOf(PACKAGE_SEPARATOR);
return (lastDotIndex != -1 ? fqClassName.substring(0, lastDotIndex) : "");
}
/**
* Return the qualified name of the given class: usually simply
* the class name, but component type class name + "[]" for arrays.
* @param clazz the class
* @return the qualified name of the class
*/
public static String getQualifiedName(Class clazz) {
Assert.notNull(clazz, "Class must not be null");
return clazz.getTypeName();
}
/**
* Return the qualified name of the given method, consisting of
* fully qualified interface/class name + "." + method name.
* @param method the method
* @return the qualified name of the method
*/
public static String getQualifiedMethodName(Method method) {
return getQualifiedMethodName(method, null);
}
/**
* Return the qualified name of the given method, consisting of
* fully qualified interface/class name + "." + method name.
* @param method the method
* @param clazz the clazz that the method is being invoked on
* (may be {@code null} to indicate the method's declaring class)
* @return the qualified name of the method
* @since 4.3.4
*/
public static String getQualifiedMethodName(Method method, @Nullable Class clazz) {
Assert.notNull(method, "Method must not be null");
return (clazz != null ? clazz : method.getDeclaringClass()).getName() + '.' + method.getName();
}
/**
* Determine whether the given class has a public constructor with the given signature.
*
Essentially translates {@code NoSuchMethodException} to "false".
* @param clazz the clazz to analyze
* @param paramTypes the parameter types of the method
* @return whether the class has a corresponding constructor
* @see Class#getConstructor
*/
public static boolean hasConstructor(Class clazz, Class... paramTypes) {
return (getConstructorIfAvailable(clazz, paramTypes) != null);
}
/**
* Determine whether the given class has a public constructor with the given signature,
* and return it if available (else return {@code null}).
*
Essentially translates {@code NoSuchMethodException} to {@code null}.
* @param clazz the clazz to analyze
* @param paramTypes the parameter types of the method
* @return the constructor, or {@code null} if not found
* @see Class#getConstructor
*/
@Nullable
public static Constructor getConstructorIfAvailable(Class clazz, Class... paramTypes) {
Assert.notNull(clazz, "Class must not be null");
try {
return clazz.getConstructor(paramTypes);
}
catch (NoSuchMethodException ex) {
return null;
}
}
/**
* Determine whether the given class has a public method with the given signature.
* @param clazz the clazz to analyze
* @param method the method to look for
* @return whether the class has a corresponding method
* @since 5.2.3
*/
public static boolean hasMethod(Class clazz, Method method) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(method, "Method must not be null");
if (clazz == method.getDeclaringClass()) {
return true;
}
String methodName = method.getName();
Class[] paramTypes = method.getParameterTypes();
return getMethodOrNull(clazz, methodName, paramTypes) != null;
}
/**
* Determine whether the given class has a public method with the given signature.
* Essentially translates {@code NoSuchMethodException} to "false".
* @param clazz the clazz to analyze
* @param methodName the name of the method
* @param paramTypes the parameter types of the method
* @return whether the class has a corresponding method
* @see Class#getMethod
*/
public static boolean hasMethod(Class clazz, String methodName, Class... paramTypes) {
return (getMethodIfAvailable(clazz, methodName, paramTypes) != null);
}
/**
* Determine whether the given class has a public method with the given signature,
* and return it if available (else throws an {@code IllegalStateException}).
*
In case of any signature specified, only returns the method if there is a
* unique candidate, i.e. a single public method with the specified name.
*
Essentially translates {@code NoSuchMethodException} to {@code IllegalStateException}.
* @param clazz the clazz to analyze
* @param methodName the name of the method
* @param paramTypes the parameter types of the method
* (may be {@code null} to indicate any signature)
* @return the method (never {@code null})
* @throws IllegalStateException if the method has not been found
* @see Class#getMethod
*/
public static Method getMethod(Class clazz, String methodName, @Nullable Class... paramTypes) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(methodName, "Method name must not be null");
if (paramTypes != null) {
try {
return clazz.getMethod(methodName, paramTypes);
}
catch (NoSuchMethodException ex) {
throw new IllegalStateException("Expected method not found: " + ex);
}
}
else {
Set candidates = findMethodCandidatesByName(clazz, methodName);
if (candidates.size() == 1) {
return candidates.iterator().next();
}
else if (candidates.isEmpty()) {
throw new IllegalStateException("Expected method not found: " + clazz.getName() + '.' + methodName);
}
else {
throw new IllegalStateException("No unique method found: " + clazz.getName() + '.' + methodName);
}
}
}
/**
* Determine whether the given class has a public method with the given signature,
* and return it if available (else return {@code null}).
* In case of any signature specified, only returns the method if there is a
* unique candidate, i.e. a single public method with the specified name.
*
Essentially translates {@code NoSuchMethodException} to {@code null}.
* @param clazz the clazz to analyze
* @param methodName the name of the method
* @param paramTypes the parameter types of the method
* (may be {@code null} to indicate any signature)
* @return the method, or {@code null} if not found
* @see Class#getMethod
*/
@Nullable
public static Method getMethodIfAvailable(Class clazz, String methodName, @Nullable Class... paramTypes) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(methodName, "Method name must not be null");
if (paramTypes != null) {
return getMethodOrNull(clazz, methodName, paramTypes);
}
else {
Set candidates = findMethodCandidatesByName(clazz, methodName);
if (candidates.size() == 1) {
return candidates.iterator().next();
}
return null;
}
}
/**
* Return the number of methods with a given name (with any argument types),
* for the given class and/or its superclasses. Includes non-public methods.
* @param clazz the clazz to check
* @param methodName the name of the method
* @return the number of methods with the given name
*/
public static int getMethodCountForName(Class clazz, String methodName) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(methodName, "Method name must not be null");
int count = 0;
Method[] declaredMethods = clazz.getDeclaredMethods();
for (Method method : declaredMethods) {
if (methodName.equals(method.getName())) {
count++;
}
}
Class[] ifcs = clazz.getInterfaces();
for (Class ifc : ifcs) {
count += getMethodCountForName(ifc, methodName);
}
if (clazz.getSuperclass() != null) {
count += getMethodCountForName(clazz.getSuperclass(), methodName);
}
return count;
}
/**
* Does the given class or one of its superclasses at least have one or more
* methods with the supplied name (with any argument types)?
* Includes non-public methods.
* @param clazz the clazz to check
* @param methodName the name of the method
* @return whether there is at least one method with the given name
*/
public static boolean hasAtLeastOneMethodWithName(Class clazz, String methodName) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(methodName, "Method name must not be null");
Method[] declaredMethods = clazz.getDeclaredMethods();
for (Method method : declaredMethods) {
if (method.getName().equals(methodName)) {
return true;
}
}
Class[] ifcs = clazz.getInterfaces();
for (Class ifc : ifcs) {
if (hasAtLeastOneMethodWithName(ifc, methodName)) {
return true;
}
}
return (clazz.getSuperclass() != null && hasAtLeastOneMethodWithName(clazz.getSuperclass(), methodName));
}
/**
* Given a method, which may come from an interface, and a target class used
* in the current reflective invocation, find the corresponding target method
* if there is one. E.g. the method may be {@code IFoo.bar()} and the
* target class may be {@code DefaultFoo}. In this case, the method may be
* {@code DefaultFoo.bar()}. This enables attributes on that method to be found.
* NOTE: In contrast to {@link org.springframework.aop.support.AopUtils#getMostSpecificMethod},
* this method does not resolve bridge methods automatically.
* Call {@link org.springframework.core.BridgeMethodResolver#findBridgedMethod}
* if bridge method resolution is desirable (e.g. for obtaining metadata from
* the original method definition).
*
NOTE: Since Spring 3.1.1, if Java security settings disallow reflective
* access (e.g. calls to {@code Class#getDeclaredMethods} etc, this implementation
* will fall back to returning the originally provided method.
* @param method the method to be invoked, which may come from an interface
* @param targetClass the target class for the current invocation
* (may be {@code null} or may not even implement the method)
* @return the specific target method, or the original method if the
* {@code targetClass} does not implement it
* @see #getInterfaceMethodIfPossible(Method, Class)
*/
public static Method getMostSpecificMethod(Method method, @Nullable Class targetClass) {
if (targetClass != null && targetClass != method.getDeclaringClass() && isOverridable(method, targetClass)) {
try {
if (Modifier.isPublic(method.getModifiers())) {
try {
return targetClass.getMethod(method.getName(), method.getParameterTypes());
}
catch (NoSuchMethodException ex) {
return method;
}
}
else {
Method specificMethod =
ReflectionUtils.findMethod(targetClass, method.getName(), method.getParameterTypes());
return (specificMethod != null ? specificMethod : method);
}
}
catch (SecurityException ex) {
// Security settings are disallowing reflective access; fall back to 'method' below.
}
}
return method;
}
/**
* Determine a corresponding interface method for the given method handle, if possible.
*
This is particularly useful for arriving at a public exported type on Jigsaw
* which can be reflectively invoked without an illegal access warning.
* @param method the method to be invoked, potentially from an implementation class
* @return the corresponding interface method, or the original method if none found
* @since 5.1
* @deprecated in favor of {@link #getInterfaceMethodIfPossible(Method, Class)}
*/
@Deprecated
public static Method getInterfaceMethodIfPossible(Method method) {
return getInterfaceMethodIfPossible(method, null);
}
/**
* Determine a corresponding interface method for the given method handle, if possible.
*
This is particularly useful for arriving at a public exported type on Jigsaw
* which can be reflectively invoked without an illegal access warning.
* @param method the method to be invoked, potentially from an implementation class
* @param targetClass the target class to check for declared interfaces
* @return the corresponding interface method, or the original method if none found
* @since 5.3.16
* @see #getMostSpecificMethod
*/
public static Method getInterfaceMethodIfPossible(Method method, @Nullable Class targetClass) {
if (!Modifier.isPublic(method.getModifiers()) || method.getDeclaringClass().isInterface()) {
return method;
}
// Try cached version of method in its declaring class
Method result = interfaceMethodCache.computeIfAbsent(method,
key -> findInterfaceMethodIfPossible(key, key.getDeclaringClass(), Object.class));
if (result == method && targetClass != null) {
// No interface method found yet -> try given target class (possibly a subclass of the
// declaring class, late-binding a base class method to a subclass-declared interface:
// see e.g. HashMap.HashIterator.hasNext)
result = findInterfaceMethodIfPossible(method, targetClass, method.getDeclaringClass());
}
return result;
}
private static Method findInterfaceMethodIfPossible(Method method, Class startClass, Class endClass) {
Class current = startClass;
while (current != null && current != endClass) {
Class[] ifcs = current.getInterfaces();
for (Class ifc : ifcs) {
try {
return ifc.getMethod(method.getName(), method.getParameterTypes());
}
catch (NoSuchMethodException ex) {
// ignore
}
}
current = current.getSuperclass();
}
return method;
}
/**
* Determine whether the given method is declared by the user or at least pointing to
* a user-declared method.
*
Checks {@link Method#isSynthetic()} (for implementation methods) as well as the
* {@code GroovyObject} interface (for interface methods; on an implementation class,
* implementations of the {@code GroovyObject} methods will be marked as synthetic anyway).
* Note that, despite being synthetic, bridge methods ({@link Method#isBridge()}) are considered
* as user-level methods since they are eventually pointing to a user-declared generic method.
* @param method the method to check
* @return {@code true} if the method can be considered as user-declared; {@code false} otherwise
*/
public static boolean isUserLevelMethod(Method method) {
Assert.notNull(method, "Method must not be null");
return (method.isBridge() || (!method.isSynthetic() && !isGroovyObjectMethod(method)));
}
private static boolean isGroovyObjectMethod(Method method) {
return method.getDeclaringClass().getName().equals("groovy.lang.GroovyObject");
}
/**
* Determine whether the given method is overridable in the given target class.
* @param method the method to check
* @param targetClass the target class to check against
*/
private static boolean isOverridable(Method method, @Nullable Class targetClass) {
if (Modifier.isPrivate(method.getModifiers())) {
return false;
}
if (Modifier.isPublic(method.getModifiers()) || Modifier.isProtected(method.getModifiers())) {
return true;
}
return (targetClass == null ||
getPackageName(method.getDeclaringClass()).equals(getPackageName(targetClass)));
}
/**
* Return a public static method of a class.
* @param clazz the class which defines the method
* @param methodName the static method name
* @param args the parameter types to the method
* @return the static method, or {@code null} if no static method was found
* @throws IllegalArgumentException if the method name is blank or the clazz is null
*/
@Nullable
public static Method getStaticMethod(Class clazz, String methodName, Class... args) {
Assert.notNull(clazz, "Class must not be null");
Assert.notNull(methodName, "Method name must not be null");
try {
Method method = clazz.getMethod(methodName, args);
return Modifier.isStatic(method.getModifiers()) ? method : null;
}
catch (NoSuchMethodException ex) {
return null;
}
}
@Nullable
private static Method getMethodOrNull(Class clazz, String methodName, Class[] paramTypes) {
try {
return clazz.getMethod(methodName, paramTypes);
}
catch (NoSuchMethodException ex) {
return null;
}
}
private static Set findMethodCandidatesByName(Class clazz, String methodName) {
Set candidates = new HashSet<>(1);
Method[] methods = clazz.getMethods();
for (Method method : methods) {
if (methodName.equals(method.getName())) {
candidates.add(method);
}
}
return candidates;
}
}