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/*
* 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.lang2;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* <p>Operates on classes without using reflection.</p>
*
* <p>This class handles invalid <code>null</code> inputs as best it can.
* Each method documents its behaviour in more detail.</p>
*
* @author Stephen Colebourne
* @author Gary Gregory
* @author Norm Deane
* @author Alban Peignier
* @since 2.0
* @version $Id$
*/
public class ClassUtils {
/**
* <p>The package separator character: <code>'&#x2e;' == {@value}</code>.</p>
*/
public static final char PACKAGE_SEPARATOR_CHAR = '.';
/**
* <p>The package separator String: <code>"&#x2e;"</code>.</p>
*/
public static final String PACKAGE_SEPARATOR = String.valueOf(PACKAGE_SEPARATOR_CHAR);
/**
* <p>The inner class separator character: <code>'$' == {@value}</code>.</p>
*/
public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
/**
* <p>The inner class separator String: <code>"$"</code>.</p>
*/
public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
/**
* Maps primitive <code>Class</code>es to their corresponding wrapper <code>Class</code>.
*/
private static Map primitiveWrapperMap = new HashMap();
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 a primitive class name to its corresponding abbreviation used in array class names.
*/
private static Map abbreviationMap = new HashMap();
static {
abbreviationMap.put( "int", "I" );
abbreviationMap.put( "boolean", "Z" );
abbreviationMap.put( "float", "F" );
abbreviationMap.put( "long", "J" );
abbreviationMap.put( "short", "S" );
abbreviationMap.put( "byte", "B" );
abbreviationMap.put( "double", "D" );
abbreviationMap.put( "char", "C" );
}
/**
* <p>ClassUtils instances should NOT be constructed in standard programming.
* Instead, the class should be used as
* <code>ClassUtils.getShortClassName(cls)</code>.</p>
*
* <p>This constructor is public to permit tools that require a JavaBean
* instance to operate.</p>
*/
public ClassUtils() {
super();
}
// Short class name
// ----------------------------------------------------------------------
/**
* <p>Gets the class name minus the package name for an <code>Object</code>.</p>
*
* @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().getName());
}
/**
* <p>Gets the class name minus the package name from a <code>Class</code>.</p>
*
* @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());
}
/**
* <p>Gets the class name minus the package name from a String.</p>
*
* <p>The string passed in is assumed to be a class name - it is not checked.</p>
*
* @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;
}
char[] chars = className.toCharArray();
int lastDot = 0;
for (int i = 0; i < chars.length; i++) {
if (chars[i] == PACKAGE_SEPARATOR_CHAR) {
lastDot = i + 1;
} else if (chars[i] == INNER_CLASS_SEPARATOR_CHAR) { // handle inner classes
chars[i] = PACKAGE_SEPARATOR_CHAR;
}
}
return new String(chars, lastDot, chars.length - lastDot);
}
// Package name
// ----------------------------------------------------------------------
/**
* <p>Gets the package name of an <code>Object</code>.</p>
*
* @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().getName());
}
/**
* <p>Gets the package name of a <code>Class</code>.</p>
*
* @param cls the class to get the package name for, may be <code>null</code>.
* @return the package name or an empty string
*/
public static String getPackageName(Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getPackageName(cls.getName());
}
/**
* <p>Gets the package name from a <code>String</code>.</p>
*
* <p>The string passed in is assumed to be a class name - it is not checked.</p>
* <p>If the class is unpackaged, return an empty string.</p>
*
* @param className the className to get the package name for, may be <code>null</code>
* @return the package name or an empty string
*/
public static String getPackageName(String className) {
if (className == null) {
return StringUtils.EMPTY;
}
int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
if (i == -1) {
return StringUtils.EMPTY;
}
return className.substring(0, i);
}
// Superclasses/Superinterfaces
// ----------------------------------------------------------------------
/**
* <p>Gets a <code>List</code> of superclasses for the given class.</p>
*
* @param cls the class to look up, may be <code>null</code>
* @return the <code>List</code> of superclasses in order going up from this one
* <code>null</code> 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;
}
/**
* <p>Gets a <code>List</code> of all interfaces implemented by the given
* class and its superclasses.</p>
*
* <p>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.</p>
*
* @param cls the class to look up, may be <code>null</code>
* @return the <code>List</code> of interfaces in order,
* <code>null</code> if null input
*/
public static List getAllInterfaces(Class cls) {
if (cls == null) {
return null;
}
List list = new ArrayList();
while (cls != null) {
Class[] interfaces = cls.getInterfaces();
for (int i = 0; i < interfaces.length; i++) {
if (list.contains(interfaces[i]) == false) {
list.add(interfaces[i]);
}
List superInterfaces = getAllInterfaces(interfaces[i]);
for (Iterator it = superInterfaces.iterator(); it.hasNext();) {
Class intface = (Class) it.next();
if (list.contains(intface) == false) {
list.add(intface);
}
}
}
cls = cls.getSuperclass();
}
return list;
}
// Convert list
// ----------------------------------------------------------------------
/**
* <p>Given a <code>List</code> of class names, this method converts them into classes.</p>
*
* <p>A new <code>List</code> is returned. If the class name cannot be found, <code>null</code>
* is stored in the <code>List</code>. If the class name in the <code>List</code> is
* <code>null</code>, <code>null</code> is stored in the output <code>List</code>.</p>
*
* @param classNames the classNames to change
* @return a <code>List</code> of Class objects corresponding to the class names,
* <code>null</code> 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 (Iterator it = classNames.iterator(); it.hasNext();) {
String className = (String) it.next();
try {
classes.add(Class.forName(className));
} catch (Exception ex) {
classes.add(null);
}
}
return classes;
}
/**
* <p>Given a <code>List</code> of <code>Class</code> objects, this method converts
* them into class names.</p>
*
* <p>A new <code>List</code> is returned. <code>null</code> objects will be copied into
* the returned list as <code>null</code>.</p>
*
* @param classes the classes to change
* @return a <code>List</code> of class names corresponding to the Class objects,
* <code>null</code> if null input
* @throws ClassCastException if <code>classes</code> contains a non-<code>Class</code> entry
*/
public static List convertClassesToClassNames(List classes) {
if (classes == null) {
return null;
}
List classNames = new ArrayList(classes.size());
for (Iterator it = classes.iterator(); it.hasNext();) {
Class cls = (Class) it.next();
if (cls == null) {
classNames.add(null);
} else {
classNames.add(cls.getName());
}
}
return classNames;
}
// Is assignable
// ----------------------------------------------------------------------
/**
* <p>Checks if an array of Classes can be assigned to another array of Classes.</p>
*
* <p>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).</p>
*
* <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method, this
* method takes into account widenings of primitive classes and
* <code>null</code>s.</p>
*
* <p>Primitive widenings allow an int to be assigned to a <code>long</code>,
* <code>float</code> or <code>double</code>. This method returns the correct
* result for these cases.</p>
*
* <p><code>Null</code> may be assigned to any reference type. This method will
* return <code>true</code> if <code>null</code> is passed in and the toClass is
* non-primitive.</p>
*
* <p>Specifically, this method tests whether the type represented by the
* specified <code>Class</code> parameter can be converted to the type
* represented by this <code>Class</code> object via an identity conversion
* widening primitive or widening reference conversion. See
* <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
*
* @param classArray the array of Classes to check, may be <code>null</code>
* @param toClassArray the array of Classes to try to assign into, may be <code>null</code>
* @return <code>true</code> if assignment possible
*/
public static boolean isAssignable(Class[] classArray, Class[] toClassArray) {
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]) == false) {
return false;
}
}
return true;
}
/**
* <p>Checks if one <code>Class</code> can be assigned to a variable of
* another <code>Class</code>.</p>
*
* <p>Unlike the {@link Class#isAssignableFrom(java.lang.Class)} method,
* this method takes into account widenings of primitive classes and
* <code>null</code>s.</p>
*
* <p>Primitive widenings allow an int to be assigned to a long, float or
* double. This method returns the correct result for these cases.</p>
*
* <p><code>Null</code> may be assigned to any reference type. This method
* will return <code>true</code> if <code>null</code> is passed in and the
* toClass is non-primitive.</p>
*
* <p>Specifically, this method tests whether the type represented by the
* specified <code>Class</code> parameter can be converted to the type
* represented by this <code>Class</code> object via an identity conversion
* widening primitive or widening reference conversion. See
* <em><a href="http://java.sun.com/docs/books/jls/">The Java Language Specification</a></em>,
* sections 5.1.1, 5.1.2 and 5.1.4 for details.</p>
*
* @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</code> if assignment possible
*/
public static boolean isAssignable(Class cls, Class toClass) {
if (toClass == null) {
return false;
}
// have to check for null, as isAssignableFrom doesn't
if (cls == null) {
return !(toClass.isPrimitive());
}
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);
}
/**
* <p>Converts the specified primitive Class object to its corresponding
* wrapper Class object.</p>
*
* <p>NOTE: From v2.2, this method handles <code>Void.TYPE</code>,
* returning <code>Void.TYPE</code>.</p>
*
* @param cls the class to convert, may be null
* @return the wrapper class for <code>cls</code> or <code>cls</code> if
* <code>cls</code> is not a primitive. <code>null</code> if null input.
* @since 2.1
*/
public static Class primitiveToWrapper(Class cls) {
Class convertedClass = cls;
if (cls != null && cls.isPrimitive()) {
convertedClass = (Class) primitiveWrapperMap.get(cls);
}
return convertedClass;
}
/**
* <p>Converts the specified array of primitive Class objects to an array of
* its corresponding wrapper Class objects.</p>
*
* @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</code> 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;
}
// Inner class
// ----------------------------------------------------------------------
/**
* <p>Is the specified class an inner class or static nested class.</p>
*
* @param cls the class to check, may be null
* @return <code>true</code> if the class is an inner or static nested class,
* false if not or <code>null</code>
*/
public static boolean isInnerClass(Class cls) {
if (cls == null) {
return false;
}
return cls.getName().indexOf(INNER_CLASS_SEPARATOR_CHAR) >= 0;
}
// Class loading
// ----------------------------------------------------------------------
/**
* Returns the class represented by <code>className</code> using the
* <code>classLoader</code>. This implementation supports names like
* "<code>java.lang.String[]</code>" as well as "<code>[Ljava.lang.String;</code>".
*
* @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</code> using the <code>classLoader</code>
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(
ClassLoader classLoader, String className, boolean initialize) throws ClassNotFoundException {
Class clazz;
if (abbreviationMap.containsKey(className)) {
String clsName = "[" + abbreviationMap.get(className);
clazz = Class.forName(clsName, initialize, classLoader).getComponentType();
} else {
clazz = Class.forName(toProperClassName(className), initialize, classLoader);
}
return clazz;
}
/**
* Returns the (initialized) class represented by <code>className</code>
* using the <code>classLoader</code>. This implementation supports names
* like "<code>java.lang.String[]</code>" as well as
* "<code>[Ljava.lang.String;</code>".
*
* @param classLoader the class loader to use to load the class
* @param className the class name
* @return the class represented by <code>className</code> using the <code>classLoader</code>
* @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</code>
* using the current thread's context class loader. This implementation
* supports names like "<code>java.lang.String[]</code>" as well as
* "<code>[Ljava.lang.String;</code>".
*
* @param className the class name
* @return the class represented by <code>className</code> 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</code> using the
* current thread's context class loader. This implementation supports
* names like "<code>java.lang.String[]</code>" as well as
* "<code>[Ljava.lang.String;</code>".
*
* @param className the class name
* @param initialize whether the class must be initialized
* @return the class represented by <code>className</code> 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
// ----------------------------------------------------------------------
/**
* <p>Returns the desired Method much like <code>Class.getMethod</code>, 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
* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4071957">4071957</a>).
*
* <code><pre>Set set = Collections.unmodifiableSet(...);
* Method method = ClassUtils.getPublicMethod(set.getClass(), "isEmpty", new Class[0]);
* Object result = method.invoke(set, new Object[]);</pre></code>
* </p>
*
* @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 (Iterator it = candidateClasses.iterator(); it.hasNext(); ) {
Class candidateClass = (Class) it.next();
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 toProperClassName(String className) {
className = StringUtils.deleteWhitespace(className);
if (className == null) {
throw new NullArgumentException("className");
} else if (className.endsWith("[]")) {
StringBuffer classNameBuffer = new StringBuffer();
while (className.endsWith("[]")) {
className = className.substring(0, className.length() - 2);
classNameBuffer.append("[");
}
String abbreviation = (String) abbreviationMap.get(className);
if (abbreviation != null) {
classNameBuffer.append(abbreviation);
} else {
classNameBuffer.append("L").append(className).append(";");
}
className = classNameBuffer.toString();
}
return className;
}
}