org.apache.commons.lang3.ClassUtils Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
/**
* Operates on classes without using reflection.
*
* This class handles invalid {@code null} inputs as best it can.
* Each method documents its behaviour in more detail.
*
* The notion of a {@code canonical name} includes the human
* readable name for the type, for example {@code int[]}. The
* non-canonical method variants work with the JVM names, such as
* {@code [I}.
*
* @since 2.0
* @version $Id: ClassUtils.java 1145035 2011-07-11 06:09:39Z bayard $
*/
public class ClassUtils {
/**
* The package separator character: '.' == {@value}.
*/
public static final char PACKAGE_SEPARATOR_CHAR = '.';
/**
* The package separator String: {@code "."}.
*/
public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
/**
* The inner class separator character: '$' == {@value}.
*/
public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
/**
* The inner class separator String: {@code "$"}.
*/
public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
/**
* Maps primitive {@code Class}es to their corresponding wrapper {@code Class}.
*/
private static final Map, Class> primitiveWrapperMap = new HashMap, Class>();
static {
primitiveWrapperMap.put(Boolean.TYPE, Boolean.class);
primitiveWrapperMap.put(Byte.TYPE, Byte.class);
primitiveWrapperMap.put(Character.TYPE, Character.class);
primitiveWrapperMap.put(Short.TYPE, Short.class);
primitiveWrapperMap.put(Integer.TYPE, Integer.class);
primitiveWrapperMap.put(Long.TYPE, Long.class);
primitiveWrapperMap.put(Double.TYPE, Double.class);
primitiveWrapperMap.put(Float.TYPE, Float.class);
primitiveWrapperMap.put(Void.TYPE, Void.TYPE);
}
/**
* Maps wrapper {@code Class}es to their corresponding primitive types.
*/
private static final Map, Class> wrapperPrimitiveMap = new HashMap, Class>();
static {
for (Class primitiveClass : primitiveWrapperMap.keySet()) {
Class wrapperClass = primitiveWrapperMap.get(primitiveClass);
if (!primitiveClass.equals(wrapperClass)) {
wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
}
}
}
/**
* Maps a primitive class name to its corresponding abbreviation used in array class names.
*/
private static final Map abbreviationMap = new HashMap();
/**
* Maps an abbreviation used in array class names to corresponding primitive class name.
*/
private static final Map reverseAbbreviationMap = new HashMap();
/**
* Add primitive type abbreviation to maps of abbreviations.
*
* @param primitive Canonical name of primitive type
* @param abbreviation Corresponding abbreviation of primitive type
*/
private static void addAbbreviation(String primitive, String abbreviation) {
abbreviationMap.put(primitive, abbreviation);
reverseAbbreviationMap.put(abbreviation, primitive);
}
/**
* Feed abbreviation maps
*/
static {
addAbbreviation("int", "I");
addAbbreviation("boolean", "Z");
addAbbreviation("float", "F");
addAbbreviation("long", "J");
addAbbreviation("short", "S");
addAbbreviation("byte", "B");
addAbbreviation("double", "D");
addAbbreviation("char", "C");
}
/**
* ClassUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as
* {@code ClassUtils.getShortClassName(cls)}.
*
* This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public ClassUtils() {
super();
}
// Short class name
// ----------------------------------------------------------------------
/**
* Gets the class name minus the package name for an {@code Object}.
*
* @param object the class to get the short name for, may be null
* @param valueIfNull the value to return if null
* @return the class name of the object without the package name, or the null value
*/
public static String getShortClassName(Object object, String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getShortClassName(object.getClass());
}
/**
* Gets the class name minus the package name from a {@code Class}.
*
* Consider using the Java 5 API {@link Class#getSimpleName()} instead.
* The one known difference is that this code will return {@code "Map.Entry"} while
* the {@code java.lang.Class} variant will simply return {@code "Entry"}.
*
* @param cls the class to get the short name for.
* @return the class name without the package name or an empty string
*/
public static String getShortClassName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getShortClassName(cls.getName());
}
/**
* Gets the class name minus the package name from a String.
*
* The string passed in is assumed to be a class name - it is not checked.
* Note that this method differs from Class.getSimpleName() in that this will
* return {@code "Map.Entry"} whilst the {@code java.lang.Class} variant will simply
* return {@code "Entry"}.
*
* @param className the className to get the short name for
* @return the class name of the class without the package name or an empty string
*/
public static String getShortClassName(String className) {
if (className == null) {
return StringUtils.EMPTY;
}
if (className.length() == 0) {
return StringUtils.EMPTY;
}
StringBuilder arrayPrefix = new StringBuilder();
// Handle array encoding
if (className.startsWith("[")) {
while (className.charAt(0) == '[') {
className = className.substring(1);
arrayPrefix.append("[]");
}
// Strip Object type encoding
if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
className = className.substring(1, className.length() - 1);
}
}
if (reverseAbbreviationMap.containsKey(className)) {
className = reverseAbbreviationMap.get(className);
}
int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
int innerIdx = className.indexOf(
INNER_CLASS_SEPARATOR_CHAR, lastDotIdx == -1 ? 0 : lastDotIdx + 1);
String out = className.substring(lastDotIdx + 1);
if (innerIdx != -1) {
out = out.replace(INNER_CLASS_SEPARATOR_CHAR, PACKAGE_SEPARATOR_CHAR);
}
return out + arrayPrefix;
}
/**
* Null-safe version of aClass.getSimpleName()
*
* @param cls the class for which to get the simple name.
* @return the simple class name.
* @since 3.0
* @see Class#getSimpleName()
*/
public static String getSimpleName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return cls.getSimpleName();
}
/**
* Null-safe version of aClass.getSimpleName()
*
* @param object the object for which to get the simple class name.
* @param valueIfNull the value to return if object is null
* @return the simple class name.
* @since 3.0
* @see Class#getSimpleName()
*/
public static String getSimpleName(Object object, String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getSimpleName(object.getClass());
}
// Package name
// ----------------------------------------------------------------------
/**
* Gets the package name of an {@code Object}.
*
* @param object the class to get the package name for, may be null
* @param valueIfNull the value to return if null
* @return the package name of the object, or the null value
*/
public static String getPackageName(Object object, String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getPackageName(object.getClass());
}
/**
* Gets the package name of a {@code Class}.
*
* @param cls the class to get the package name for, may be {@code null}.
* @return the package name or an empty string
*/
public static String getPackageName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getPackageName(cls.getName());
}
/**
* Gets the package name from a {@code String}.
*
* The string passed in is assumed to be a class name - it is not checked.
* If the class is unpackaged, return an empty string.
*
* @param className the className to get the package name for, may be {@code null}
* @return the package name or an empty string
*/
public static String getPackageName(String className) {
if (className == null || className.length() == 0) {
return StringUtils.EMPTY;
}
// Strip array encoding
while (className.charAt(0) == '[') {
className = className.substring(1);
}
// Strip Object type encoding
if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';') {
className = className.substring(1);
}
int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
if (i == -1) {
return StringUtils.EMPTY;
}
return className.substring(0, i);
}
// Superclasses/Superinterfaces
// ----------------------------------------------------------------------
/**
* Gets a {@code List} of superclasses for the given class.
*
* @param cls the class to look up, may be {@code null}
* @return the {@code List} of superclasses in order going up from this one
* {@code null} if null input
*/
public static List> getAllSuperclasses(Class cls) {
if (cls == null) {
return null;
}
List> classes = new ArrayList>();
Class superclass = cls.getSuperclass();
while (superclass != null) {
classes.add(superclass);
superclass = superclass.getSuperclass();
}
return classes;
}
/**
* Gets a {@code List} of all interfaces implemented by the given
* class and its superclasses.
*
* The order is determined by looking through each interface in turn as
* declared in the source file and following its hierarchy up. Then each
* superclass is considered in the same way. Later duplicates are ignored,
* so the order is maintained.
*
* @param cls the class to look up, may be {@code null}
* @return the {@code List} of interfaces in order,
* {@code null} if null input
*/
public static List> getAllInterfaces(Class cls) {
if (cls == null) {
return null;
}
LinkedHashSet> interfacesFound = new LinkedHashSet>();
getAllInterfaces(cls, interfacesFound);
return new ArrayList>(interfacesFound);
}
/**
* Get the interfaces for the specified class.
*
* @param cls the class to look up, may be {@code null}
* @param interfacesFound the {@code Set} of interfaces for the class
*/
private static void getAllInterfaces(Class cls, HashSet> interfacesFound) {
while (cls != null) {
Class[] interfaces = cls.getInterfaces();
for (Class i : interfaces) {
if (interfacesFound.add(i)) {
getAllInterfaces(i, interfacesFound);
}
}
cls = cls.getSuperclass();
}
}
// Convert list
// ----------------------------------------------------------------------
/**
* Given a {@code List} of class names, this method converts them into classes.
*
* A new {@code List} is returned. If the class name cannot be found, {@code null}
* is stored in the {@code List}. If the class name in the {@code List} is
* {@code null}, {@code null} is stored in the output {@code List}.
*
* @param classNames the classNames to change
* @return a {@code List} of Class objects corresponding to the class names,
* {@code null} if null input
* @throws ClassCastException if classNames contains a non String entry
*/
public static List> convertClassNamesToClasses(List classNames) {
if (classNames == null) {
return null;
}
List> classes = new ArrayList>(classNames.size());
for (String className : classNames) {
try {
classes.add(Class.forName(className));
} catch (Exception ex) {
classes.add(null);
}
}
return classes;
}
/**
* Given a {@code List} of {@code Class} objects, this method converts
* them into class names.
*
* A new {@code List} is returned. {@code null} objects will be copied into
* the returned list as {@code null}.
*
* @param classes the classes to change
* @return a {@code List} of class names corresponding to the Class objects,
* {@code null} if null input
* @throws ClassCastException if {@code classes} contains a non-{@code Class} entry
*/
public static List convertClassesToClassNames(List> classes) {
if (classes == null) {
return null;
}
List classNames = new ArrayList(classes.size());
for (Class cls : classes) {
if (cls == null) {
classNames.add(null);
} else {
classNames.add(cls.getName());
}
}
return classNames;
}
// Is assignable
// ----------------------------------------------------------------------
/**
* Checks if an array of Classes can be assigned to another array of Classes.
*
* This method calls {@link #isAssignable(Class, Class) isAssignable} for each
* Class pair in the input arrays. It can be used to check if a set of arguments
* (the first parameter) are suitably compatible with a set of method parameter types
* (the second parameter).
*
* Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
* method takes into account widenings of primitive classes and
* {@code null}s.
*
* Primitive widenings allow an int to be assigned to a {@code long},
* {@code float} or {@code double}. This method returns the correct
* result for these cases.
*
* {@code Null} may be assigned to any reference type. This method will
* return {@code true} if {@code null} is passed in and the toClass is
* non-primitive.
*
* Specifically, this method tests whether the type represented by the
* specified {@code Class} parameter can be converted to the type
* represented by this {@code Class} object via an identity conversion
* widening primitive or widening reference conversion. See
* The Java Language Specification,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.
*
* Since Lang 3.0, this method will default behavior for
* calculating assignability between primitive and wrapper types corresponding
* to the running Java version; i.e. autoboxing will be the default
* behavior in VMs running Java versions >= 1.5.
*
* @param classArray the array of Classes to check, may be {@code null}
* @param toClassArray the array of Classes to try to assign into, may be {@code null}
* @return {@code true} if assignment possible
*/
public static boolean isAssignable(Class[] classArray, Class... toClassArray) {
return isAssignable(classArray, toClassArray, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
}
/**
* Checks if an array of Classes can be assigned to another array of Classes.
*
* This method calls {@link #isAssignable(Class, Class) isAssignable} for each
* Class pair in the input arrays. It can be used to check if a set of arguments
* (the first parameter) are suitably compatible with a set of method parameter types
* (the second parameter).
*
* Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
* method takes into account widenings of primitive classes and
* {@code null}s.
*
* Primitive widenings allow an int to be assigned to a {@code long},
* {@code float} or {@code double}. This method returns the correct
* result for these cases.
*
* {@code Null} may be assigned to any reference type. This method will
* return {@code true} if {@code null} is passed in and the toClass is
* non-primitive.
*
* Specifically, this method tests whether the type represented by the
* specified {@code Class} parameter can be converted to the type
* represented by this {@code Class} object via an identity conversion
* widening primitive or widening reference conversion. See
* The Java Language Specification,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.
*
* @param classArray the array of Classes to check, may be {@code null}
* @param toClassArray the array of Classes to try to assign into, may be {@code null}
* @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
* @return {@code true} if assignment possible
*/
public static boolean isAssignable(Class[] classArray, Class[] toClassArray, boolean autoboxing) {
if (ArrayUtils.isSameLength(classArray, toClassArray) == false) {
return false;
}
if (classArray == null) {
classArray = ArrayUtils.EMPTY_CLASS_ARRAY;
}
if (toClassArray == null) {
toClassArray = ArrayUtils.EMPTY_CLASS_ARRAY;
}
for (int i = 0; i < classArray.length; i++) {
if (isAssignable(classArray[i], toClassArray[i], autoboxing) == false) {
return false;
}
}
return true;
}
/**
* Checks if one {@code Class} can be assigned to a variable of
* another {@code Class}.
*
* Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
* this method takes into account widenings of primitive classes and
* {@code null}s.
*
* Primitive widenings allow an int to be assigned to a long, float or
* double. This method returns the correct result for these cases.
*
* {@code Null} may be assigned to any reference type. This method
* will return {@code true} if {@code null} is passed in and the
* toClass is non-primitive.
*
* Specifically, this method tests whether the type represented by the
* specified {@code Class} parameter can be converted to the type
* represented by this {@code Class} object via an identity conversion
* widening primitive or widening reference conversion. See
* The Java Language Specification,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.
*
* Since Lang 3.0, this method will default behavior for
* calculating assignability between primitive and wrapper types corresponding
* to the running Java version; i.e. autoboxing will be the default
* behavior in VMs running Java versions >= 1.5.
*
* @param cls the Class to check, may be null
* @param toClass the Class to try to assign into, returns false if null
* @return {@code true} if assignment possible
*/
public static boolean isAssignable(Class cls, Class toClass) {
return isAssignable(cls, toClass, SystemUtils.isJavaVersionAtLeast(JavaVersion.JAVA_1_5));
}
/**
* Checks if one {@code Class} can be assigned to a variable of
* another {@code Class}.
*
* Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
* this method takes into account widenings of primitive classes and
* {@code null}s.
*
* Primitive widenings allow an int to be assigned to a long, float or
* double. This method returns the correct result for these cases.
*
* {@code Null} may be assigned to any reference type. This method
* will return {@code true} if {@code null} is passed in and the
* toClass is non-primitive.
*
* Specifically, this method tests whether the type represented by the
* specified {@code Class} parameter can be converted to the type
* represented by this {@code Class} object via an identity conversion
* widening primitive or widening reference conversion. See
* The Java Language Specification,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.
*
* @param cls the Class to check, may be null
* @param toClass the Class to try to assign into, returns false if null
* @param autoboxing whether to use implicit autoboxing/unboxing between primitives and wrappers
* @return {@code true} if assignment possible
*/
public static boolean isAssignable(Class cls, Class toClass, boolean autoboxing) {
if (toClass == null) {
return false;
}
// have to check for null, as isAssignableFrom doesn't
if (cls == null) {
return !(toClass.isPrimitive());
}
//autoboxing:
if (autoboxing) {
if (cls.isPrimitive() && !toClass.isPrimitive()) {
cls = primitiveToWrapper(cls);
if (cls == null) {
return false;
}
}
if (toClass.isPrimitive() && !cls.isPrimitive()) {
cls = wrapperToPrimitive(cls);
if (cls == null) {
return false;
}
}
}
if (cls.equals(toClass)) {
return true;
}
if (cls.isPrimitive()) {
if (toClass.isPrimitive() == false) {
return false;
}
if (Integer.TYPE.equals(cls)) {
return Long.TYPE.equals(toClass)
|| Float.TYPE.equals(toClass)
|| Double.TYPE.equals(toClass);
}
if (Long.TYPE.equals(cls)) {
return Float.TYPE.equals(toClass)
|| Double.TYPE.equals(toClass);
}
if (Boolean.TYPE.equals(cls)) {
return false;
}
if (Double.TYPE.equals(cls)) {
return false;
}
if (Float.TYPE.equals(cls)) {
return Double.TYPE.equals(toClass);
}
if (Character.TYPE.equals(cls)) {
return Integer.TYPE.equals(toClass)
|| Long.TYPE.equals(toClass)
|| Float.TYPE.equals(toClass)
|| Double.TYPE.equals(toClass);
}
if (Short.TYPE.equals(cls)) {
return Integer.TYPE.equals(toClass)
|| Long.TYPE.equals(toClass)
|| Float.TYPE.equals(toClass)
|| Double.TYPE.equals(toClass);
}
if (Byte.TYPE.equals(cls)) {
return Short.TYPE.equals(toClass)
|| Integer.TYPE.equals(toClass)
|| Long.TYPE.equals(toClass)
|| Float.TYPE.equals(toClass)
|| Double.TYPE.equals(toClass);
}
// should never get here
return false;
}
return toClass.isAssignableFrom(cls);
}
/**
* Converts the specified primitive Class object to its corresponding
* wrapper Class object.
*
* NOTE: From v2.2, this method handles {@code Void.TYPE},
* returning {@code Void.TYPE}.
*
* @param cls the class to convert, may be null
* @return the wrapper class for {@code cls} or {@code cls} if
* {@code cls} is not a primitive. {@code null} if null input.
* @since 2.1
*/
public static Class primitiveToWrapper(Class cls) {
Class convertedClass = cls;
if (cls != null && cls.isPrimitive()) {
convertedClass = primitiveWrapperMap.get(cls);
}
return convertedClass;
}
/**
* Converts the specified array of primitive Class objects to an array of
* its corresponding wrapper Class objects.
*
* @param classes the class array to convert, may be null or empty
* @return an array which contains for each given class, the wrapper class or
* the original class if class is not a primitive. {@code null} if null input.
* Empty array if an empty array passed in.
* @since 2.1
*/
public static Class[] primitivesToWrappers(Class... classes) {
if (classes == null) {
return null;
}
if (classes.length == 0) {
return classes;
}
Class[] convertedClasses = new Class[classes.length];
for (int i = 0; i < classes.length; i++) {
convertedClasses[i] = primitiveToWrapper(classes[i]);
}
return convertedClasses;
}
/**
* Converts the specified wrapper class to its corresponding primitive
* class.
*
* This method is the counter part of {@code primitiveToWrapper()}.
* If the passed in class is a wrapper class for a primitive type, this
* primitive type will be returned (e.g. {@code Integer.TYPE} for
* {@code Integer.class}). For other classes, or if the parameter is
* null, the return value is null.
*
* @param cls the class to convert, may be null
* @return the corresponding primitive type if {@code cls} is a
* wrapper class, null otherwise
* @see #primitiveToWrapper(Class)
* @since 2.4
*/
public static Class wrapperToPrimitive(Class cls) {
return wrapperPrimitiveMap.get(cls);
}
/**
* Converts the specified array of wrapper Class objects to an array of
* its corresponding primitive Class objects.
*
* This method invokes {@code wrapperToPrimitive()} for each element
* of the passed in array.
*
* @param classes the class array to convert, may be null or empty
* @return an array which contains for each given class, the primitive class or
* null if the original class is not a wrapper class. {@code null} if null input.
* Empty array if an empty array passed in.
* @see #wrapperToPrimitive(Class)
* @since 2.4
*/
public static Class[] wrappersToPrimitives(Class... classes) {
if (classes == null) {
return null;
}
if (classes.length == 0) {
return classes;
}
Class[] convertedClasses = new Class[classes.length];
for (int i = 0; i < classes.length; i++) {
convertedClasses[i] = wrapperToPrimitive(classes[i]);
}
return convertedClasses;
}
// Inner class
// ----------------------------------------------------------------------
/**
* Is the specified class an inner class or static nested class.
*
* @param cls the class to check, may be null
* @return {@code true} if the class is an inner or static nested class,
* false if not or {@code null}
*/
public static boolean isInnerClass(Class cls) {
return cls != null && cls.getEnclosingClass() != null;
}
// Class loading
// ----------------------------------------------------------------------
/**
* Returns the class represented by {@code className} using the
* {@code classLoader}. This implementation supports the syntaxes
* "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
* "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
*
* @param classLoader the class loader to use to load the class
* @param className the class name
* @param initialize whether the class must be initialized
* @return the class represented by {@code className} using the {@code classLoader}
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(
ClassLoader classLoader, String className, boolean initialize) throws ClassNotFoundException {
try {
Class clazz;
if (abbreviationMap.containsKey(className)) {
String clsName = "[" + abbreviationMap.get(className);
clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
} else {
clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
}
return clazz;
} catch (ClassNotFoundException ex) {
// allow path separators (.) as inner class name separators
int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
if (lastDotIndex != -1) {
try {
return getClass(classLoader, className.substring(0, lastDotIndex) +
INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
initialize);
} catch (ClassNotFoundException ex2) { // NOPMD
// ignore exception
}
}
throw ex;
}
}
/**
* Returns the (initialized) class represented by {@code className}
* using the {@code classLoader}. This implementation supports
* the syntaxes "{@code java.util.Map.Entry[]}",
* "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
* and "{@code [Ljava.util.Map$Entry;}".
*
* @param classLoader the class loader to use to load the class
* @param className the class name
* @return the class represented by {@code className} using the {@code classLoader}
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(ClassLoader classLoader, String className) throws ClassNotFoundException {
return getClass(classLoader, className, true);
}
/**
* Returns the (initialized) class represented by {@code className}
* using the current thread's context class loader. This implementation
* supports the syntaxes "{@code java.util.Map.Entry[]}",
* "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
* and "{@code [Ljava.util.Map$Entry;}".
*
* @param className the class name
* @return the class represented by {@code className} using the current thread's context class loader
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(String className) throws ClassNotFoundException {
return getClass(className, true);
}
/**
* Returns the class represented by {@code className} using the
* current thread's context class loader. This implementation supports the
* syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$Entry[]}",
* "{@code [Ljava.util.Map.Entry;}", and "{@code [Ljava.util.Map$Entry;}".
*
* @param className the class name
* @param initialize whether the class must be initialized
* @return the class represented by {@code className} using the current thread's context class loader
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(String className, boolean initialize) throws ClassNotFoundException {
ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
ClassLoader loader = contextCL == null ? ClassUtils.class.getClassLoader() : contextCL;
return getClass(loader, className, initialize );
}
// Public method
// ----------------------------------------------------------------------
/**
* Returns the desired Method much like {@code Class.getMethod}, however
* it ensures that the returned Method is from a public class or interface and not
* from an anonymous inner class. This means that the Method is invokable and
* doesn't fall foul of Java bug
* 4071957).
*
* Set set = Collections.unmodifiableSet(...);
* Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty", new Class[0]);
* Object result = method.invoke(set, new Object[]);
*
* @param cls the class to check, not null
* @param methodName the name of the method
* @param parameterTypes the list of parameters
* @return the method
* @throws NullPointerException if the class is null
* @throws SecurityException if a a security violation occured
* @throws NoSuchMethodException if the method is not found in the given class
* or if the metothod doen't conform with the requirements
*/
public static Method getPublicMethod(Class cls, String methodName, Class... parameterTypes)
throws SecurityException, NoSuchMethodException {
Method declaredMethod = cls.getMethod(methodName, parameterTypes);
if (Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())) {
return declaredMethod;
}
List> candidateClasses = new ArrayList>();
candidateClasses.addAll(getAllInterfaces(cls));
candidateClasses.addAll(getAllSuperclasses(cls));
for (Class candidateClass : candidateClasses) {
if (!Modifier.isPublic(candidateClass.getModifiers())) {
continue;
}
Method candidateMethod;
try {
candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
} catch (NoSuchMethodException ex) {
continue;
}
if (Modifier.isPublic(candidateMethod.getDeclaringClass().getModifiers())) {
return candidateMethod;
}
}
throw new NoSuchMethodException("Can't find a public method for " +
methodName + " " + ArrayUtils.toString(parameterTypes));
}
// ----------------------------------------------------------------------
/**
* Converts a class name to a JLS style class name.
*
* @param className the class name
* @return the converted name
*/
private static String toCanonicalName(String className) {
className = StringUtils.deleteWhitespace(className);
if (className == null) {
throw new NullPointerException("className must not be null.");
} else if (className.endsWith("[]")) {
StringBuilder classNameBuffer = new StringBuilder();
while (className.endsWith("[]")) {
className = className.substring(0, className.length() - 2);
classNameBuffer.append("[");
}
String abbreviation = abbreviationMap.get(className);
if (abbreviation != null) {
classNameBuffer.append(abbreviation);
} else {
classNameBuffer.append("L").append(className).append(";");
}
className = classNameBuffer.toString();
}
return className;
}
/**
* Converts an array of {@code Object} in to an array of {@code Class} objects.
* If any of these objects is null, a null element will be inserted into the array.
*
* This method returns {@code null} for a {@code null} input array.
*
* @param array an {@code Object} array
* @return a {@code Class} array, {@code null} if null array input
* @since 2.4
*/
public static Class[] toClass(Object... array) {
if (array == null) {
return null;
} else if (array.length == 0) {
return ArrayUtils.EMPTY_CLASS_ARRAY;
}
Class[] classes = new Class[array.length];
for (int i = 0; i < array.length; i++) {
classes[i] = array[i] == null ? null : array[i].getClass();
}
return classes;
}
// Short canonical name
// ----------------------------------------------------------------------
/**
* Gets the canonical name minus the package name for an {@code Object}.
*
* @param object the class to get the short name for, may be null
* @param valueIfNull the value to return if null
* @return the canonical name of the object without the package name, or the null value
* @since 2.4
*/
public static String getShortCanonicalName(Object object, String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getShortCanonicalName(object.getClass().getName());
}
/**
* Gets the canonical name minus the package name from a {@code Class}.
*
* @param cls the class to get the short name for.
* @return the canonical name without the package name or an empty string
* @since 2.4
*/
public static String getShortCanonicalName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getShortCanonicalName(cls.getName());
}
/**
* Gets the canonical name minus the package name from a String.
*
* The string passed in is assumed to be a canonical name - it is not checked.
*
* @param canonicalName the class name to get the short name for
* @return the canonical name of the class without the package name or an empty string
* @since 2.4
*/
public static String getShortCanonicalName(String canonicalName) {
return ClassUtils.getShortClassName(getCanonicalName(canonicalName));
}
// Package name
// ----------------------------------------------------------------------
/**
* Gets the package name from the canonical name of an {@code Object}.
*
* @param object the class to get the package name for, may be null
* @param valueIfNull the value to return if null
* @return the package name of the object, or the null value
* @since 2.4
*/
public static String getPackageCanonicalName(Object object, String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getPackageCanonicalName(object.getClass().getName());
}
/**
* Gets the package name from the canonical name of a {@code Class}.
*
* @param cls the class to get the package name for, may be {@code null}.
* @return the package name or an empty string
* @since 2.4
*/
public static String getPackageCanonicalName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getPackageCanonicalName(cls.getName());
}
/**
* Gets the package name from the canonical name.
*
* The string passed in is assumed to be a canonical name - it is not checked.
* If the class is unpackaged, return an empty string.
*
* @param canonicalName the canonical name to get the package name for, may be {@code null}
* @return the package name or an empty string
* @since 2.4
*/
public static String getPackageCanonicalName(String canonicalName) {
return ClassUtils.getPackageName(getCanonicalName(canonicalName));
}
/**
* Converts a given name of class into canonical format.
* If name of class is not a name of array class it returns
* unchanged name.
* Example:
*
* - {@code getCanonicalName("[I") = "int[]"}
* - {@code getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"}
* - {@code getCanonicalName("java.lang.String") = "java.lang.String"}
*
*
*
* @param className the name of class
* @return canonical form of class name
* @since 2.4
*/
private static String getCanonicalName(String className) {
className = StringUtils.deleteWhitespace(className);
if (className == null) {
return null;
} else {
int dim = 0;
while (className.startsWith("[")) {
dim++;
className = className.substring(1);
}
if (dim < 1) {
return className;
} else {
if (className.startsWith("L")) {
className = className.substring(
1,
className.endsWith(";")
? className.length() - 1
: className.length());
} else {
if (className.length() > 0) {
className = reverseAbbreviationMap.get(className.substring(0, 1));
}
}
StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
for (int i = 0; i < dim; i++) {
canonicalClassNameBuffer.append("[]");
}
return canonicalClassNameBuffer.toString();
}
}
}
}