org.ehcache.impl.internal.classes.commonslang.ClassUtils Maven / Gradle / Ivy
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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.
*/
/*
* This is a modified version of the original Apache class. It has had unused
* members removed.
*/
package org.ehcache.impl.internal.classes.commonslang;
import java.util.HashMap;
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
*/
public class ClassUtils {
/**
* 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 (final Map.Entry, Class> entry : primitiveWrapperMap.entrySet()) {
final Class primitiveClass = entry.getKey();
final Class wrapperClass = entry.getValue();
if (!primitiveClass.equals(wrapperClass)) {
wrapperPrimitiveMap.put(wrapperClass, primitiveClass);
}
}
}
/**
* 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();
}
/**
* 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, final 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(final Class cls, final 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, final Class toClass, final 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(final Class cls) {
Class convertedClass = cls;
if (cls != null && cls.isPrimitive()) {
convertedClass = primitiveWrapperMap.get(cls);
}
return convertedClass;
}
/**
* 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(final Class cls) {
return wrapperPrimitiveMap.get(cls);
}
/**
* 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(final Object... array) {
if (array == null) {
return null;
} else if (array.length == 0) {
return ArrayUtils.EMPTY_CLASS_ARRAY;
}
final 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;
}
}