| /* |
| * Copyright 2002-2005 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.lang; |
| |
| 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>'.' == {@value}</code>.</p> |
| */ |
| public static final char PACKAGE_SEPARATOR_CHAR = '.'; |
| |
| /** |
| * <p>The package separator String: <code>"."</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); |
| } |
| |
| /** |
| * <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; |
| } |
| |
| } |
