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.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.mutable.MutableObject;
/**
* Operates on classes without using reflection.
*
* This class handles invalid {@code null} inputs as best it can.
* Each method documents its behavior 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 {
/**
* Inclusivity literals for {@link #hierarchy(Class, Interfaces)}.
* @since 3.2
*/
public enum Interfaces {
/** Includes interfaces. */
INCLUDE,
/** Excludes interfaces. */
EXCLUDE
}
/**
* The package separator character: {@code '.' == {@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: {@code '$' == {@value}}.
*/
public static final char INNER_CLASS_SEPARATOR_CHAR = '$';
/**
* The inner class separator String: {@code "$"}.
*/
public static final String INNER_CLASS_SEPARATOR = String.valueOf(INNER_CLASS_SEPARATOR_CHAR);
/**
* Maps names of primitives to their corresponding primitive {@code Class}es.
*/
private static final Map> namePrimitiveMap = new HashMap<>();
static {
namePrimitiveMap.put("boolean", Boolean.TYPE);
namePrimitiveMap.put("byte", Byte.TYPE);
namePrimitiveMap.put("char", Character.TYPE);
namePrimitiveMap.put("short", Short.TYPE);
namePrimitiveMap.put("int", Integer.TYPE);
namePrimitiveMap.put("long", Long.TYPE);
namePrimitiveMap.put("double", Double.TYPE);
namePrimitiveMap.put("float", Float.TYPE);
namePrimitiveMap.put("void", Void.TYPE);
}
/**
* Maps primitive {@code Class}es to their corresponding wrapper {@code Class}.
*/
private static final Map, Class> 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 wrapper {@code Class}es to their corresponding primitive types.
*/
private static final Map, Class> wrapperPrimitiveMap = new HashMap<>();
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);
}
}
}
/**
* Maps a primitive class name to its corresponding abbreviation used in array class names.
*/
private static final Map abbreviationMap;
/**
* Maps an abbreviation used in array class names to corresponding primitive class name.
*/
private static final Map reverseAbbreviationMap;
// Feed abbreviation maps
static {
final Map m = new HashMap<>();
m.put("int", "I");
m.put("boolean", "Z");
m.put("float", "F");
m.put("long", "J");
m.put("short", "S");
m.put("byte", "B");
m.put("double", "D");
m.put("char", "C");
final Map r = new HashMap<>();
for (final Map.Entry e : m.entrySet()) {
r.put(e.getValue(), e.getKey());
}
abbreviationMap = Collections.unmodifiableMap(m);
reverseAbbreviationMap = Collections.unmodifiableMap(r);
}
/**
* 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() {
}
// Short class name
// ----------------------------------------------------------------------
/**
* Gets the class name of the {@code object} without the package name or names.
*
* The method looks up the class of the object and then converts the name of the class invoking
* {@link #getShortClassName(Class)} (see relevant notes there).
*
* @param object the class to get the short name for, may be {@code null}
* @param valueIfNull the value to return if the object is {@code null}
* @return the class name of the object without the package name, or {@code valueIfNull}
* if the argument {@code object} is {@code null}
*/
public static String getShortClassName(final Object object, final String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getShortClassName(object.getClass());
}
/**
* Gets the class name minus the package name from a {@code Class}.
*
* This method simply gets the name using {@code Class.getName()} and then calls
* {@link #getShortClassName(Class)}. See relevant notes there.
*
* @param cls the class to get the short name for.
* @return the class name without the package name or an empty string. If the class
* is an inner class then the returned value will contain the outer class
* or classes separated with {@code .} (dot) character.
*/
public static String getShortClassName(final 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. The string has to be formatted the way
* as the JDK method {@code Class.getName()} returns it, and not the usual way as we write it, for example in import
* statements, or as it is formatted by {@code Class.getCanonicalName()}.
*
* The difference is is significant only in case of classes that are inner classes of some other
* classes. In this case the separator between the outer and inner class (possibly on multiple hierarchy level) has
* to be {@code $} (dollar sign) and not {@code .} (dot), as it is returned by {@code Class.getName()}
*
* Note that this method is called from the {@link #getShortClassName(Class)} method using the string
* returned by {@code Class.getName()}.
*
* Note that this method differs from {@link #getSimpleName(Class)} in that this will
* return, for example {@code "Map.Entry"} whilst the {@code java.lang.Class} variant will simply
* return {@code "Entry"}. In this example the argument {@code className} is the string
* {@code java.util.Map$Entry} (note the {@code $} sign.
*
* @param className the className to get the short name for. It has to be formatted as returned by
* {@code Class.getName()} and not {@code Class.getCanonicalName()}
* @return the class name of the class without the package name or an empty string. If the class is
* an inner class then value contains the outer class or classes and the separator is replaced
* to be {@code .} (dot) character.
*/
public static String getShortClassName(String className) {
if (StringUtils.isEmpty(className)) {
return StringUtils.EMPTY;
}
final 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);
}
}
final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
final 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 {@code cls.getSimpleName()}
*
* @param cls the class for which to get the simple name; may be null
* @return the simple class name or the empty string in case the argument is {@code null}
* @since 3.0
* @see Class#getSimpleName()
*/
public static String getSimpleName(final Class cls) {
return getSimpleName(cls, StringUtils.EMPTY);
}
/**
* Null-safe version of {@code cls.getSimpleName()}
*
* @param cls the class for which to get the simple name; may be null
* @param valueIfNull the value to return if null
* @return the simple class name or {@code valueIfNull} if the
* argument {@code cls} is {@code null}
* @since 3.0
* @see Class#getSimpleName()
*/
public static String getSimpleName(final Class cls, final String valueIfNull) {
return cls == null ? valueIfNull : cls.getSimpleName();
}
/**
* Null-safe version of {@code object.getClass().getSimpleName()}
*
* It is to note that this method is overloaded and in case the argument {@code object} is a
* {@code Class} object then the {@link #getSimpleName(Class)} will be invoked. If this is
* a significant possibility then the caller should check this case and call {@code
* getSimpleName(Class.class)} or just simply use the string literal {@code "Class"}, which
* is the result of the method in that case.
*
* @param object the object for which to get the simple class name; may be null
* @return the simple class name or the empty string in case the argument is {@code null}
* @since 3.7
* @see Class#getSimpleName()
*/
public static String getSimpleName(final Object object) {
return getSimpleName(object, StringUtils.EMPTY);
}
/**
* Null-safe version of {@code object.getClass().getSimpleName()}
*
* @param object the object for which to get the simple class name; may be null
* @param valueIfNull the value to return if {@code object} is {@code null}
* @return the simple class name or {@code valueIfNull} if the
* argument {@code object} is {@code null}
* @since 3.0
* @see Class#getSimpleName()
*/
public static String getSimpleName(final Object object, final String valueIfNull) {
return object == null ? valueIfNull : object.getClass().getSimpleName();
}
/**
* Null-safe version of {@code cls.getName()}
*
* @param cls the class for which to get the class name; may be null
* @return the class name or the empty string in case the argument is {@code null}
* @since 3.7
* @see Class#getSimpleName()
*/
public static String getName(final Class cls) {
return getName(cls, StringUtils.EMPTY);
}
/**
* Null-safe version of {@code cls.getName()}
*
* @param cls the class for which to get the class name; may be null
* @param valueIfNull the return value if the argument {@code cls} is {@code null}
* @return the class name or {@code valueIfNull}
* @since 3.7
* @see Class#getName()
*/
public static String getName(final Class cls, final String valueIfNull) {
return cls == null ? valueIfNull : cls.getName();
}
/**
* Null-safe version of {@code object.getClass().getName()}
*
* @param object the object for which to get the class name; may be null
* @return the class name or the empty String
* @since 3.7
* @see Class#getSimpleName()
*/
public static String getName(final Object object) {
return getName(object, StringUtils.EMPTY);
}
/**
* Null-safe version of {@code object.getClass().getSimpleName()}
*
* @param object the object for which to get the class name; may be null
* @param valueIfNull the value to return if {@code object} is {@code null}
* @return the class name or {@code valueIfNull}
* @since 3.0
* @see Class#getName()
*/
public static String getName(final Object object, final String valueIfNull) {
return object == null ? valueIfNull : object.getClass().getName();
}
// 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(final Object object, final 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(final 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 (StringUtils.isEmpty(className)) {
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);
}
final int i = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
if (i == -1) {
return StringUtils.EMPTY;
}
return className.substring(0, i);
}
// Abbreviated name
// ----------------------------------------------------------------------
/**
* Gets the abbreviated name of a {@code Class}.
*
* @param cls the class to get the abbreviated name for, may be {@code null}
* @param lengthHint the desired length of the abbreviated name
* @return the abbreviated name or an empty string
* @throws IllegalArgumentException if len <= 0
* @see #getAbbreviatedName(String, int)
* @since 3.4
*/
public static String getAbbreviatedName(final Class cls, final int lengthHint) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getAbbreviatedName(cls.getName(), lengthHint);
}
/**
* Gets the abbreviated class name from a {@code String}.
*
* The string passed in is assumed to be a class name - it is not checked.
*
* The abbreviation algorithm will shorten the class name, usually without
* significant loss of meaning.
*
* The abbreviated class name will always include the complete package hierarchy.
* If enough space is available, rightmost sub-packages will be displayed in full
* length. The abbreviated package names will be shortened to a single character.
* Only package names are shortened, the class simple name remains untouched. (See examples.)
* The result will be longer than the desired length only if all the package names
* shortened to a single character plus the class simple name with the separating dots
* together are longer than the desired length. In other words, when the class name
* cannot be shortened to the desired length.
* If the class name can be shortened then
* the final length will be at most {@code lengthHint} characters.
* If the {@code lengthHint} is zero or negative then the method
* throws exception. If you want to achieve the shortest possible version then
* use {@code 1} as a {@code lengthHint}.
*
*
* Examples
* className len return null 1 "" "java.lang.String" 5 "j.l.String" "java.lang.String" 15 "j.lang.String" "java.lang.String" 30 "java.lang.String" "org.apache.commons.lang3.ClassUtils" 18 "o.a.c.l.ClassUtils"
*
* @param className the className to get the abbreviated name for, may be {@code null}
* @param lengthHint the desired length of the abbreviated name
* @return the abbreviated name or an empty string if the specified
* class name is {@code null} or empty string. The abbreviated name may be
* longer than the desired length if it cannot be abbreviated to the desired length.
* @throws IllegalArgumentException if {@code len <= 0}
* @since 3.4
*/
public static String getAbbreviatedName(final String className, final int lengthHint) {
if (lengthHint <= 0) {
throw new IllegalArgumentException("len must be > 0");
}
if (className == null) {
return StringUtils.EMPTY;
}
if (className.length() <= lengthHint) {
return className;
}
final char[] abbreviated = className.toCharArray();
int target = 0;
int source = 0;
while (source < abbreviated.length) {
// copy the next part
int runAheadTarget = target;
while (source < abbreviated.length && abbreviated[source] != '.') {
abbreviated[runAheadTarget++] = abbreviated[source++];
}
++target;
if (useFull(runAheadTarget, source, abbreviated.length, lengthHint)
|| target > runAheadTarget) {
target = runAheadTarget;
}
// copy the '.' unless it was the last part
if (source < abbreviated.length) {
abbreviated[target++] = abbreviated[source++];
}
}
return new String(abbreviated, 0, target);
}
/**
* Decides if the part that was just copied to its destination
* location in the work array can be kept as it was copied or must be
* abbreviated. It must be kept when the part is the last one, which
* is the simple name of the class. In this case the {@code source}
* index, from where the characters are copied points one position
* after the last character, a.k.a. {@code source ==
* originalLength}
*
* If the part is not the last one then it can be kept
* unabridged if the number of the characters copied so far plus
* the character that are to be copied is less than or equal to the
* desired length.
*
* @param runAheadTarget the target index (where the characters were
* copied to) pointing after the last character
* copied when the current part was copied
* @param source the source index (where the characters were
* copied from) pointing after the last
* character copied when the current part was
* copied
* @param originalLength the original length of the class full name,
* which is abbreviated
* @param desiredLength the desired length of the abbreviated class
* name
* @return {@code true} if it can be kept in its original length
* {@code false} if the current part has to be abbreviated and
*/
private static boolean useFull(final int runAheadTarget,
final int source,
final int originalLength,
final int desiredLength) {
return source >= originalLength ||
runAheadTarget + originalLength - source <= desiredLength;
}
// 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(final Class cls) {
if (cls == null) {
return null;
}
final 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(final Class cls) {
if (cls == null) {
return null;
}
final LinkedHashSet> interfacesFound = new LinkedHashSet<>();
getAllInterfaces(cls, interfacesFound);
return new ArrayList<>(interfacesFound);
}
/**
* Gets 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, final HashSet> interfacesFound) {
while (cls != null) {
final Class[] interfaces = cls.getInterfaces();
for (final 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(final List classNames) {
if (classNames == null) {
return null;
}
final List> classes = new ArrayList<>(classNames.size());
for (final String className : classNames) {
try {
classes.add(Class.forName(className));
} catch (final 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(final List> classes) {
if (classes == null) {
return null;
}
final List classNames = new ArrayList<>(classes.size());
for (final 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(final Class[] classArray, final Class... toClassArray) {
return isAssignable(classArray, toClassArray, true);
}
/**
* 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)) {
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)) {
return false;
}
}
return true;
}
/**
* Returns whether the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
* {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
*
* @param type
* The class to query or null.
* @return true if the given {@code type} is a primitive or primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character},
* {@link Short}, {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
* @since 3.1
*/
public static boolean isPrimitiveOrWrapper(final Class type) {
if (type == null) {
return false;
}
return type.isPrimitive() || isPrimitiveWrapper(type);
}
/**
* Returns whether the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character}, {@link Short},
* {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
*
* @param type
* The class to query or null.
* @return true if the given {@code type} is a primitive wrapper ({@link Boolean}, {@link Byte}, {@link Character}, {@link Short},
* {@link Integer}, {@link Long}, {@link Double}, {@link Float}).
* @since 3.1
*/
public static boolean isPrimitiveWrapper(final Class type) {
return wrapperPrimitiveMap.containsKey(type);
}
/**
* 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, 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.
*
* @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()) {
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 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(final Class... classes) {
if (classes == null) {
return null;
}
if (classes.length == 0) {
return classes;
}
final 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(final 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(final Class... classes) {
if (classes == null) {
return null;
}
if (classes.length == 0) {
return classes;
}
final 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(final 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$Entry;}".
*
* @param classLoader the class loader to use to load the class
* @param className the class name
* @param initialize whether the class must be initialized
* @return the class represented by {@code className} using the {@code classLoader}
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(
final ClassLoader classLoader, final String className, final boolean initialize) throws ClassNotFoundException {
try {
final Class clazz;
if (namePrimitiveMap.containsKey(className)) {
clazz = namePrimitiveMap.get(className);
} else {
clazz = Class.forName(toCanonicalName(className), initialize, classLoader);
}
return clazz;
} catch (final ClassNotFoundException ex) {
// allow path separators (.) as inner class name separators
final int lastDotIndex = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
if (lastDotIndex != -1) {
try {
return getClass(classLoader, className.substring(0, lastDotIndex) +
INNER_CLASS_SEPARATOR_CHAR + className.substring(lastDotIndex + 1),
initialize);
} catch (final ClassNotFoundException ex2) { // NOPMD
// ignore exception
}
}
throw ex;
}
}
/**
* Returns the (initialized) class represented by {@code className}
* using the {@code classLoader}. This implementation supports
* the syntaxes "{@code java.util.Map.Entry[]}",
* "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
* and "{@code [Ljava.util.Map$Entry;}".
*
* @param classLoader the class loader to use to load the class
* @param className the class name
* @return the class represented by {@code className} using the {@code classLoader}
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(final ClassLoader classLoader, final String className) throws ClassNotFoundException {
return getClass(classLoader, className, true);
}
/**
* Returns the (initialized) class represented by {@code className}
* using the current thread's context class loader. This implementation
* supports the syntaxes "{@code java.util.Map.Entry[]}",
* "{@code java.util.Map$Entry[]}", "{@code [Ljava.util.Map.Entry;}",
* and "{@code [Ljava.util.Map$Entry;}".
*
* @param className the class name
* @return the class represented by {@code className} using the current thread's context class loader
* @throws ClassNotFoundException if the class is not found
*/
public static Class getClass(final String className) throws ClassNotFoundException {
return getClass(className, true);
}
/**
* Returns the class represented by {@code className} using the
* current thread's context class loader. This implementation supports the
* syntaxes "{@code java.util.Map.Entry[]}", "{@code java.util.Map$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(final String className, final boolean initialize) throws ClassNotFoundException {
final ClassLoader contextCL = Thread.currentThread().getContextClassLoader();
final 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 security violation occurred
* @throws NoSuchMethodException if the method is not found in the given class
* or if the method doesn't conform with the requirements
*/
public static Method getPublicMethod(final Class cls, final String methodName, final Class... parameterTypes)
throws NoSuchMethodException {
final Method declaredMethod = cls.getMethod(methodName, parameterTypes);
if (Modifier.isPublic(declaredMethod.getDeclaringClass().getModifiers())) {
return declaredMethod;
}
final List> candidateClasses = new ArrayList<>(getAllInterfaces(cls));
candidateClasses.addAll(getAllSuperclasses(cls));
for (final Class candidateClass : candidateClasses) {
if (!Modifier.isPublic(candidateClass.getModifiers())) {
continue;
}
final Method candidateMethod;
try {
candidateMethod = candidateClass.getMethod(methodName, parameterTypes);
} catch (final 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);
Validate.notNull(className, "className");
if (className.endsWith("[]")) {
final StringBuilder classNameBuffer = new StringBuilder();
while (className.endsWith("[]")) {
className = className.substring(0, className.length() - 2);
classNameBuffer.append("[");
}
final 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(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;
}
// 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(final Object object, final String valueIfNull) {
if (object == null) {
return valueIfNull;
}
return getShortCanonicalName(object.getClass().getName());
}
/**
* Gets the canonical class name for a {@code Class}.
*
* @param cls the class for which to get the canonical class name; may be null
* @return the canonical name of the class, or the empty String
* @since 3.7
* @see Class#getCanonicalName()
*/
public static String getCanonicalName(final Class cls) {
return getCanonicalName(cls, StringUtils.EMPTY);
}
/**
* Gets the canonical name for a {@code Class}.
*
* @param cls the class for which to get the canonical class name; may be null
* @param valueIfNull the return value if null
* @return the canonical name of the class, or {@code valueIfNull}
* @since 3.7
* @see Class#getCanonicalName()
*/
public static String getCanonicalName(final Class cls, final String valueIfNull) {
if (cls == null) {
return valueIfNull;
}
final String canonicalName = cls.getCanonicalName();
return canonicalName == null ? valueIfNull : canonicalName;
}
/**
* Gets the canonical name for an {@code Object}.
*
* @param object the object for which to get the canonical class name; may be null
* @return the canonical name of the object, or the empty String
* @since 3.7
* @see Class#getCanonicalName()
*/
public static String getCanonicalName(final Object object) {
return getCanonicalName(object, StringUtils.EMPTY);
}
/**
* Gets the canonical name for an {@code Object}.
*
* @param object the object for which to get the canonical class name; may be null
* @param valueIfNull the return value if null
* @return the canonical name of the object or {@code valueIfNull}
* @since 3.7
* @see Class#getCanonicalName()
*/
public static String getCanonicalName(final Object object, final String valueIfNull) {
if (object == null) {
return valueIfNull;
}
final String canonicalName = object.getClass().getCanonicalName();
return canonicalName == null ? valueIfNull : canonicalName;
}
/**
* Gets the canonical name minus the package name from a {@code Class}.
*
* @param cls the class for which to get the short canonical class name; may be null
* @return the canonical name without the package name or an empty string
* @since 2.4
*/
public static String getShortCanonicalName(final 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 class name - it is not checked.
*
* Note that this method is mainly designed to handle the arrays and primitives properly.
* If the class is an inner class then the result value will not contain the outer classes.
* This way the behavior of this method is different from {@link #getShortClassName(String)}.
* The argument in that case is class name and not canonical name and the return value
* retains the outer classes.
*
* Note that there is no way to reliably identify the part of the string representing the
* package hierarchy and the part that is the outer class or classes in case of an inner class.
* Trying to find the class would require reflective call and the class itself may not even be
* on the class path. Relying on the fact that class names start with capital letter and packages
* with lower case is heuristic.
*
* It is recommended to use {@link #getShortClassName(String)} for cases when the class
* is an inner class and use this method for cases it is designed for.
*
*
* Examples
* return value input {@code ""} {@code (String)null} {@code "Map.Entry"} {@code java.util.Map.Entry.class.getName()} {@code "Entry"} {@code java.util.Map.Entry.class.getCanonicalName()} {@code "ClassUtils"} {@code "org.apache.commons.lang3.ClassUtils"} {@code "ClassUtils[]"} {@code "[Lorg.apache.commons.lang3.ClassUtils;"} {@code "ClassUtils[][]"} {@code "[[Lorg.apache.commons.lang3.ClassUtils;"} {@code "ClassUtils[]"} {@code "org.apache.commons.lang3.ClassUtils[]"} {@code "ClassUtils[][]"} {@code "org.apache.commons.lang3.ClassUtils[][]"} {@code "int[]"} {@code "[I"} {@code "int[]"} {@code int[].class.getCanonicalName()} {@code "int[]"} {@code int[].class.getName()} {@code "int[][]"} {@code "[[I"} {@code "int[]"} {@code "int[]"} {@code "int[][]"} {@code "int[][]"}
*
* @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(final String canonicalName) {
return getShortClassName(getCanonicalName(canonicalName));
}
// Package name
// ----------------------------------------------------------------------
/**
* Gets the package name from the class 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(final Object object, final 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(final Class cls) {
if (cls == null) {
return StringUtils.EMPTY;
}
return getPackageCanonicalName(cls.getName());
}
/**
* Gets the package name from the class name.
*
* The string passed in is assumed to be a class name - it is not checked.
* If the class is in the default package, return an empty string.
*
* @param name the 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(final String name) {
return getPackageName(getCanonicalName(name));
}
/**
* Converts a given name of class into canonical format.
* If name of class is not a name of array class it returns
* unchanged name.
*
* The method does not change the {@code $} separators in case
* the class is inner class.
*
* 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;
}
int dim = 0;
while (className.startsWith("[")) {
dim++;
className = className.substring(1);
}
if (dim < 1) {
return className;
}
if (className.startsWith("L")) {
className = className.substring(
1,
className.endsWith(";")
? className.length() - 1
: className.length());
} else if (!className.isEmpty()) {
className = reverseAbbreviationMap.get(className.substring(0, 1));
}
final StringBuilder canonicalClassNameBuffer = new StringBuilder(className);
for (int i = 0; i < dim; i++) {
canonicalClassNameBuffer.append("[]");
}
return canonicalClassNameBuffer.toString();
}
/**
* Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
* excluding interfaces.
*
* @param type the type to get the class hierarchy from
* @return Iterable an Iterable over the class hierarchy of the given class
* @since 3.2
*/
public static Iterable> hierarchy(final Class type) {
return hierarchy(type, Interfaces.EXCLUDE);
}
/**
* Gets an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
*
* @param type the type to get the class hierarchy from
* @param interfacesBehavior switch indicating whether to include or exclude interfaces
* @return Iterable an Iterable over the class hierarchy of the given class
* @since 3.2
*/
public static Iterable> hierarchy(final Class type, final Interfaces interfacesBehavior) {
final Iterable> classes = () -> {
final MutableObject> next = new MutableObject<>(type);
return new Iterator>() {
@Override
public boolean hasNext() {
return next.getValue() != null;
}
@Override
public Class next() {
final Class result = next.getValue();
next.setValue(result.getSuperclass());
return result;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
};
if (interfacesBehavior != Interfaces.INCLUDE) {
return classes;
}
return () -> {
final Set> seenInterfaces = new HashSet<>();
final Iterator> wrapped = classes.iterator();
return new Iterator>() {
Iterator> interfaces = Collections.>emptySet().iterator();
@Override
public boolean hasNext() {
return interfaces.hasNext() || wrapped.hasNext();
}
@Override
public Class next() {
if (interfaces.hasNext()) {
final Class nextInterface = interfaces.next();
seenInterfaces.add(nextInterface);
return nextInterface;
}
final Class nextSuperclass = wrapped.next();
final Set> currentInterfaces = new LinkedHashSet<>();
walkInterfaces(currentInterfaces, nextSuperclass);
interfaces = currentInterfaces.iterator();
return nextSuperclass;
}
private void walkInterfaces(final Set> addTo, final Class c) {
for (final Class iface : c.getInterfaces()) {
if (!seenInterfaces.contains(iface)) {
addTo.add(iface);
}
walkInterfaces(addTo, iface);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
};
}
}