org.apache.commons.lang3

Class ClassUtils

java.lang.Object

org.apache.commons.lang3.ClassUtils

public class ClassUtils
extends java.lang.Object

Operates on classes without using reflection.

This class handles invalid null inputs as best it can. Each method documents its behavior in more detail.

The notion of a canonical name includes the human readable name for the type, for example int[]. The non-canonical method variants work with the JVM names, such as [I.

Since:

2.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ClassUtils.Interfaces Inclusivity literals for hierarchy(Class, Interfaces).

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	INNER_CLASS_SEPARATOR The inner class separator String: "$".
static char	INNER_CLASS_SEPARATOR_CHAR The inner class separator character: '$' == {@value}.
static java.lang.String	PACKAGE_SEPARATOR The package separator String: ".".
static char	PACKAGE_SEPARATOR_CHAR The package separator character: '.' == {@value}.

Constructor Summary

Constructors

Constructor and Description
ClassUtils() ClassUtils instances should NOT be constructed in standard programming.

Method Summary

Modifier and Type	Method and Description
static java.util.Comparator<java.lang.Class<?>>	comparator() Gets the class comparator, comparing by class name.
static java.util.List<java.lang.String>	convertClassesToClassNames(java.util.List<java.lang.Class<?>> classes) Given a List of Class objects, this method converts them into class names.
static java.util.List<java.lang.Class<?>>	convertClassNamesToClasses(java.util.List<java.lang.String> classNames) Given a List of class names, this method converts them into classes.
static java.lang.String	getAbbreviatedName(java.lang.Class<?> cls, int lengthHint) Gets the abbreviated name of a Class.
static java.lang.String	getAbbreviatedName(java.lang.String className, int lengthHint) Gets the abbreviated class name from a String.
static java.util.List<java.lang.Class<?>>	getAllInterfaces(java.lang.Class<?> cls) Gets a List of all interfaces implemented by the given class and its superclasses.
static java.util.List<java.lang.Class<?>>	getAllSuperclasses(java.lang.Class<?> cls) Gets a List of superclasses for the given class.
static java.lang.String	getCanonicalName(java.lang.Class<?> cls) Gets the canonical class name for a Class.
static java.lang.String	getCanonicalName(java.lang.Class<?> cls, java.lang.String valueIfNull) Gets the canonical name for a Class.
static java.lang.String	getCanonicalName(java.lang.Object object) Gets the canonical name for an Object.
static java.lang.String	getCanonicalName(java.lang.Object object, java.lang.String valueIfNull) Gets the canonical name for an Object.
static java.lang.Class<?>	getClass(java.lang.ClassLoader classLoader, java.lang.String className) Returns the (initialized) class represented by className using the classLoader.
static java.lang.Class<?>	getClass(java.lang.ClassLoader classLoader, java.lang.String className, boolean initialize) Returns the class represented by className using the classLoader.
static java.lang.Class<?>	getClass(java.lang.String className) Returns the (initialized) class represented by className using the current thread's context class loader.
static java.lang.Class<?>	getClass(java.lang.String className, boolean initialize) Returns the class represented by className using the current thread's context class loader.
static <T> java.lang.Class<T>	getComponentType(java.lang.Class<T[]> cls) Delegates to Class.getComponentType() using generics.
static java.lang.String	getName(java.lang.Class<?> cls) Null-safe version of cls.getName()
static java.lang.String	getName(java.lang.Class<?> cls, java.lang.String valueIfNull) Null-safe version of cls.getName()
static java.lang.String	getName(java.lang.Object object) Null-safe version of object.getClass().getName()
static java.lang.String	getName(java.lang.Object object, java.lang.String valueIfNull) Null-safe version of object.getClass().getSimpleName()
static java.lang.String	getPackageCanonicalName(java.lang.Class<?> cls) Gets the package name from the canonical name of a Class.
static java.lang.String	getPackageCanonicalName(java.lang.Object object, java.lang.String valueIfNull) Gets the package name from the class name of an Object.
static java.lang.String	getPackageCanonicalName(java.lang.String name) Gets the package name from the class name.
static java.lang.String	getPackageName(java.lang.Class<?> cls) Gets the package name of a Class.
static java.lang.String	getPackageName(java.lang.Object object, java.lang.String valueIfNull) Gets the package name of an Object.
static java.lang.String	getPackageName(java.lang.String className) Gets the package name from a String.
static java.lang.reflect.Method	getPublicMethod(java.lang.Class<?> cls, java.lang.String methodName, java.lang.Class<?>... parameterTypes) Returns the desired Method much like Class.getMethod, however it ensures that the returned Method is from a public class or interface and not from an anonymous inner class.
static java.lang.String	getShortCanonicalName(java.lang.Class<?> cls) Gets the canonical name minus the package name from a Class.
static java.lang.String	getShortCanonicalName(java.lang.Object object, java.lang.String valueIfNull) Gets the canonical name minus the package name for an Object.
static java.lang.String	getShortCanonicalName(java.lang.String canonicalName) Gets the canonical name minus the package name from a String.
static java.lang.String	getShortClassName(java.lang.Class<?> cls) Gets the class name minus the package name from a Class.
static java.lang.String	getShortClassName(java.lang.Object object, java.lang.String valueIfNull) Gets the class name of the object without the package name or names.
static java.lang.String	getShortClassName(java.lang.String className) Gets the class name minus the package name from a String.
static java.lang.String	getSimpleName(java.lang.Class<?> cls) Null-safe version of cls.getSimpleName()
static java.lang.String	getSimpleName(java.lang.Class<?> cls, java.lang.String valueIfNull) Null-safe version of cls.getSimpleName()
static java.lang.String	getSimpleName(java.lang.Object object) Null-safe version of object.getClass().getSimpleName()
static java.lang.String	getSimpleName(java.lang.Object object, java.lang.String valueIfNull) Null-safe version of object.getClass().getSimpleName()
static java.lang.Iterable<java.lang.Class<?>>	hierarchy(java.lang.Class<?> type) Gets an Iterable that can iterate over a class hierarchy in ascending (subclass to superclass) order, excluding interfaces.
static java.lang.Iterable<java.lang.Class<?>>	hierarchy(java.lang.Class<?> type, ClassUtils.Interfaces interfacesBehavior) Gets an Iterable that can iterate over a class hierarchy in ascending (subclass to superclass) order.
static boolean	isAssignable(java.lang.Class<?>[] classArray, java.lang.Class<?>... toClassArray) Checks if an array of Classes can be assigned to another array of Classes.
static boolean	isAssignable(java.lang.Class<?>[] classArray, java.lang.Class<?>[] toClassArray, boolean autoboxing) Checks if an array of Classes can be assigned to another array of Classes.
static boolean	isAssignable(java.lang.Class<?> cls, java.lang.Class<?> toClass) Checks if one Class can be assigned to a variable of another Class.
static boolean	isAssignable(java.lang.Class<?> cls, java.lang.Class<?> toClass, boolean autoboxing) Checks if one Class can be assigned to a variable of another Class.
static boolean	isInnerClass(java.lang.Class<?> cls) Is the specified class an inner class or static nested class.
static boolean	isPrimitiveOrWrapper(java.lang.Class<?> type) Returns whether the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).
static boolean	isPrimitiveWrapper(java.lang.Class<?> type) Returns whether the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).
static boolean	isPublic(java.lang.Class<?> cls) Tests whether a Class is public.
static java.lang.Class<?>[]	primitivesToWrappers(java.lang.Class<?>... classes) Converts the specified array of primitive Class objects to an array of its corresponding wrapper Class objects.
static java.lang.Class<?>	primitiveToWrapper(java.lang.Class<?> cls) Converts the specified primitive Class object to its corresponding wrapper Class object.
static java.lang.Class<?>[]	toClass(java.lang.Object... array) Converts an array of Object in to an array of Class objects.
static java.lang.Class<?>[]	wrappersToPrimitives(java.lang.Class<?>... classes) Converts the specified array of wrapper Class objects to an array of its corresponding primitive Class objects.
static java.lang.Class<?>	wrapperToPrimitive(java.lang.Class<?> cls) Converts the specified wrapper class to its corresponding primitive class.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PACKAGE_SEPARATOR_CHAR

public static final char PACKAGE_SEPARATOR_CHAR

The package separator character: '.' == {@value}.

See Also:

Constant Field Values

PACKAGE_SEPARATOR

public static final java.lang.String PACKAGE_SEPARATOR

The package separator String: ".".

INNER_CLASS_SEPARATOR_CHAR

public static final char INNER_CLASS_SEPARATOR_CHAR

The inner class separator character: '$' == {@value}.

See Also:

Constant Field Values

INNER_CLASS_SEPARATOR

public static final java.lang.String INNER_CLASS_SEPARATOR

The inner class separator String: "$".

Constructor Detail

ClassUtils

public ClassUtils()

ClassUtils instances should NOT be constructed in standard programming. Instead, the class should be used as ClassUtils.getShortClassName(cls).

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

comparator

public static java.util.Comparator<java.lang.Class<?>> comparator()

Gets the class comparator, comparing by class name.

Returns:

the class comparator.

Since:

3.13.0

convertClassesToClassNames

public static java.util.List<java.lang.String> convertClassesToClassNames(java.util.List<java.lang.Class<?>> classes)

Given a List of Class objects, this method converts them into class names.

A new List is returned. null objects will be copied into the returned list as null.

Parameters:

classes - the classes to change

Returns:

a List of class names corresponding to the Class objects, null if null input

Throws:

java.lang.ClassCastException - if classes contains a non-Class entry

convertClassNamesToClasses

public static java.util.List<java.lang.Class<?>> convertClassNamesToClasses(java.util.List<java.lang.String> classNames)

Given a List of class names, this method converts them into classes.

A new List is returned. If the class name cannot be found, null is stored in the List. If the class name in the List is null, null is stored in the output List.

Parameters:

classNames - the classNames to change

Returns:

a List of Class objects corresponding to the class names, null if null input

Throws:

java.lang.ClassCastException - if classNames contains a non String entry

getAbbreviatedName

public static java.lang.String getAbbreviatedName(java.lang.Class<?> cls,
                                                  int lengthHint)

Gets the abbreviated name of a Class.

Parameters:

cls - the class to get the abbreviated name for, may be null

lengthHint - the desired length of the abbreviated name

Returns:

the abbreviated name or an empty string

Throws:

java.lang.IllegalArgumentException - if len <= 0

Since:

3.4

See Also:

getAbbreviatedName(String, int)

getAbbreviatedName

public static java.lang.String getAbbreviatedName(java.lang.String className,
                                                  int lengthHint)

Gets the abbreviated class name from a 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 lengthHint characters.

If the lengthHint is zero or negative then the method throws exception. If you want to achieve the shortest possible version then use 1 as a 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"

Parameters:

className - the className to get the abbreviated name for, may be null

lengthHint - the desired length of the abbreviated name

Returns:

the abbreviated name or an empty string if the specified class name is null or empty string. The abbreviated name may be longer than the desired length if it cannot be abbreviated to the desired length.

Throws:

java.lang.IllegalArgumentException - if len <= 0

Since:

3.4

getAllInterfaces

public static java.util.List<java.lang.Class<?>> getAllInterfaces(java.lang.Class<?> cls)

Gets a 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.

Parameters:

cls - the class to look up, may be null

Returns:

the List of interfaces in order, null if null input

getAllSuperclasses

public static java.util.List<java.lang.Class<?>> getAllSuperclasses(java.lang.Class<?> cls)

Gets a List of superclasses for the given class.

Parameters:

cls - the class to look up, may be null

Returns:

the List of superclasses in order going up from this one null if null input

getCanonicalName

public static java.lang.String getCanonicalName(java.lang.Class<?> cls)

Gets the canonical class name for a Class.

Parameters:

cls - the class for which to get the canonical class name; may be null

Returns:

the canonical name of the class, or the empty String

Since:

3.7

See Also:

Class.getCanonicalName()

getCanonicalName

public static java.lang.String getCanonicalName(java.lang.Class<?> cls,
                                                java.lang.String valueIfNull)

Gets the canonical name for a Class.

Parameters:

cls - the class for which to get the canonical class name; may be null

valueIfNull - the return value if null

Returns:

the canonical name of the class, or valueIfNull

Since:

3.7

See Also:

Class.getCanonicalName()

getCanonicalName

public static java.lang.String getCanonicalName(java.lang.Object object)

Gets the canonical name for an Object.

Parameters:

object - the object for which to get the canonical class name; may be null

Returns:

the canonical name of the object, or the empty String

Since:

3.7

See Also:

Class.getCanonicalName()

getCanonicalName

public static java.lang.String getCanonicalName(java.lang.Object object,
                                                java.lang.String valueIfNull)

Gets the canonical name for an Object.

Parameters:

object - the object for which to get the canonical class name; may be null

valueIfNull - the return value if null

Returns:

the canonical name of the object or valueIfNull

Since:

3.7

See Also:

Class.getCanonicalName()

getClass

public static java.lang.Class<?> getClass(java.lang.ClassLoader classLoader,
                                          java.lang.String className)
                                   throws java.lang.ClassNotFoundException

Returns the (initialized) class represented by className using the classLoader. This implementation supports the syntaxes "java.util.Map.Entry[]", "java.util.Map$Entry[]", "[Ljava.util.Map.Entry;", and "[Ljava.util.Map$Entry;".

Parameters:

classLoader - the class loader to use to load the class

className - the class name

Returns:

the class represented by className using the classLoader

Throws:

java.lang.NullPointerException - if the className is null

java.lang.ClassNotFoundException - if the class is not found

getClass

public static java.lang.Class<?> getClass(java.lang.ClassLoader classLoader,
                                          java.lang.String className,
                                          boolean initialize)
                                   throws java.lang.ClassNotFoundException

Returns the class represented by className using the classLoader. This implementation supports the syntaxes "java.util.Map.Entry[]", "java.util.Map$Entry[]", "[Ljava.util.Map.Entry;", and "[Ljava.util.Map$Entry;".

Parameters:

classLoader - the class loader to use to load the class

className - the class name

initialize - whether the class must be initialized

Returns:

the class represented by className using the classLoader

Throws:

java.lang.NullPointerException - if the className is null

java.lang.ClassNotFoundException - if the class is not found

getClass

public static java.lang.Class<?> getClass(java.lang.String className)
                                   throws java.lang.ClassNotFoundException

Returns the (initialized) class represented by className using the current thread's context class loader. This implementation supports the syntaxes "java.util.Map.Entry[]", "java.util.Map$Entry[]", "[Ljava.util.Map.Entry;", and "[Ljava.util.Map$Entry;".

Parameters:

className - the class name

Returns:

the class represented by className using the current thread's context class loader

Throws:

java.lang.NullPointerException - if the className is null

java.lang.ClassNotFoundException - if the class is not found

getClass

public static java.lang.Class<?> getClass(java.lang.String className,
                                          boolean initialize)
                                   throws java.lang.ClassNotFoundException

Returns the class represented by className using the current thread's context class loader. This implementation supports the syntaxes "java.util.Map.Entry[]", "java.util.Map$Entry[]", "[Ljava.util.Map.Entry;", and "[Ljava.util.Map$Entry;".

Parameters:

className - the class name

initialize - whether the class must be initialized

Returns:

the class represented by className using the current thread's context class loader

Throws:

java.lang.NullPointerException - if the className is null

java.lang.ClassNotFoundException - if the class is not found

getComponentType

public static <T> java.lang.Class<T> getComponentType(java.lang.Class<T[]> cls)

Delegates to Class.getComponentType() using generics.

Type Parameters:

T - The array class type.

Parameters:

cls - A class or null.

Returns:

The array component type or null.

Since:

3.13.0

See Also:

Class.getComponentType()

getName

public static java.lang.String getName(java.lang.Class<?> cls)

Null-safe version of cls.getName()

Parameters:

cls - the class for which to get the class name; may be null

Returns:

the class name or the empty string in case the argument is null

Since:

3.7

See Also:

Class.getSimpleName()

getName

public static java.lang.String getName(java.lang.Class<?> cls,
                                       java.lang.String valueIfNull)

Null-safe version of cls.getName()

Parameters:

cls - the class for which to get the class name; may be null

valueIfNull - the return value if the argument cls is null

Returns:

the class name or valueIfNull

Since:

3.7

See Also:

Class.getName()

getName

public static java.lang.String getName(java.lang.Object object)

Null-safe version of object.getClass().getName()

Parameters:

object - the object for which to get the class name; may be null

Returns:

the class name or the empty String

Since:

3.7

See Also:

Class.getSimpleName()

getName

public static java.lang.String getName(java.lang.Object object,
                                       java.lang.String valueIfNull)

Null-safe version of object.getClass().getSimpleName()

Parameters:

object - the object for which to get the class name; may be null

valueIfNull - the value to return if object is null

Returns:

the class name or valueIfNull

Since:

3.0

See Also:

Class.getName()

getPackageCanonicalName

public static java.lang.String getPackageCanonicalName(java.lang.Class<?> cls)

Gets the package name from the canonical name of a Class.

Parameters:

cls - the class to get the package name for, may be null.

Returns:

the package name or an empty string

Since:

2.4

getPackageCanonicalName

public static java.lang.String getPackageCanonicalName(java.lang.Object object,
                                                       java.lang.String valueIfNull)

Gets the package name from the class name of an Object.

Parameters:

object - the class to get the package name for, may be null

valueIfNull - the value to return if null

Returns:

the package name of the object, or the null value

Since:

2.4

getPackageCanonicalName

public static java.lang.String getPackageCanonicalName(java.lang.String name)

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.

Parameters:

name - the name to get the package name for, may be null

Returns:

the package name or an empty string

Since:

2.4

getPackageName

public static java.lang.String getPackageName(java.lang.Class<?> cls)

Gets the package name of a Class.

Parameters:

cls - the class to get the package name for, may be null.

Returns:

the package name or an empty string

getPackageName

public static java.lang.String getPackageName(java.lang.Object object,
                                              java.lang.String valueIfNull)

Gets the package name of an Object.

Parameters:

object - the class to get the package name for, may be null

valueIfNull - the value to return if null

Returns:

the package name of the object, or the null value

getPackageName

public static java.lang.String getPackageName(java.lang.String className)

Gets the package name from a 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.

Parameters:

className - the className to get the package name for, may be null

Returns:

the package name or an empty string

getPublicMethod

public static java.lang.reflect.Method getPublicMethod(java.lang.Class<?> cls,
                                                       java.lang.String methodName,
                                                       java.lang.Class<?>... parameterTypes)
                                                throws java.lang.NoSuchMethodException

Returns the desired Method much like 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[]);
 

Parameters:

cls - the class to check, not null

methodName - the name of the method

parameterTypes - the list of parameters

Returns:

the method

Throws:

java.lang.NullPointerException - if the class is null

java.lang.SecurityException - if a security violation occurred

java.lang.NoSuchMethodException - if the method is not found in the given class or if the method doesn't conform with the requirements

getShortCanonicalName

public static java.lang.String getShortCanonicalName(java.lang.Class<?> cls)

Gets the canonical name minus the package name from a Class.

Parameters:

cls - the class for which to get the short canonical class name; may be null

Returns:

the canonical name without the package name or an empty string

Since:

2.4

See Also:

Class.getCanonicalName()

getShortCanonicalName

public static java.lang.String getShortCanonicalName(java.lang.Object object,
                                                     java.lang.String valueIfNull)

Gets the canonical name minus the package name for an Object.

Parameters:

object - the class to get the short name for, may be null

valueIfNull - the value to return if null

Returns:

the canonical name of the object without the package name, or the null value

Since:

2.4

See Also:

Class.getCanonicalName()

getShortCanonicalName

public static java.lang.String getShortCanonicalName(java.lang.String canonicalName)

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 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 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
""	(String)null
"Map.Entry"	java.util.Map.Entry.class.getName()
"Entry"	java.util.Map.Entry.class.getCanonicalName()
"ClassUtils"	"org.apache.commons.lang3.ClassUtils"
"ClassUtils[]"	"[Lorg.apache.commons.lang3.ClassUtils;"
"ClassUtils[][]"	"[[Lorg.apache.commons.lang3.ClassUtils;"
"ClassUtils[]"	"org.apache.commons.lang3.ClassUtils[]"
"ClassUtils[][]"	"org.apache.commons.lang3.ClassUtils[][]"
"int[]"	"[I"
"int[]"	int[].class.getCanonicalName()
"int[]"	int[].class.getName()
"int[][]"	"[[I"
"int[]"	"int[]"
"int[][]"	"int[][]"

Parameters:

canonicalName - the class name to get the short name for

Returns:

the canonical name of the class without the package name or an empty string

Since:

2.4

getShortClassName

public static java.lang.String getShortClassName(java.lang.Class<?> cls)

Gets the class name minus the package name from a Class.

This method simply gets the name using Class.getName() and then calls getShortClassName(Class). See relevant notes there.

Parameters:

cls - the class to get the short name for.

Returns:

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 . (dot) character.

getShortClassName

public static java.lang.String getShortClassName(java.lang.Object object,
                                                 java.lang.String valueIfNull)

Gets the class name of the 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 getShortClassName(Class) (see relevant notes there).

Parameters:

object - the class to get the short name for, may be null

valueIfNull - the value to return if the object is null

Returns:

the class name of the object without the package name, or valueIfNull if the argument object is null

getShortClassName

public static java.lang.String getShortClassName(java.lang.String className)

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 Class.getName() returns it, and not the usual way as we write it, for example in import statements, or as it is formatted by 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 $ (dollar sign) and not . (dot), as it is returned by Class.getName()

Note that this method is called from the getShortClassName(Class) method using the string returned by Class.getName().

Note that this method differs from getSimpleName(Class) in that this will return, for example "Map.Entry" whilst the java.lang.Class variant will simply return "Entry". In this example the argument className is the string java.util.Map$Entry (note the $ sign.

Parameters:

className - the className to get the short name for. It has to be formatted as returned by Class.getName() and not Class.getCanonicalName()

Returns:

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 . (dot) character.

getSimpleName

public static java.lang.String getSimpleName(java.lang.Class<?> cls)

Null-safe version of cls.getSimpleName()

Parameters:

cls - the class for which to get the simple name; may be null

Returns:

the simple class name or the empty string in case the argument is null

Since:

3.0

See Also:

Class.getSimpleName()

getSimpleName

public static java.lang.String getSimpleName(java.lang.Class<?> cls,
                                             java.lang.String valueIfNull)

Null-safe version of cls.getSimpleName()

Parameters:

cls - the class for which to get the simple name; may be null

valueIfNull - the value to return if null

Returns:

the simple class name or valueIfNull if the argument cls is null

Since:

3.0

See Also:

Class.getSimpleName()

getSimpleName

public static java.lang.String getSimpleName(java.lang.Object object)

Null-safe version of object.getClass().getSimpleName()

It is to note that this method is overloaded and in case the argument object is a Class object then the getSimpleName(Class) will be invoked. If this is a significant possibility then the caller should check this case and call getSimpleName(Class.class) or just simply use the string literal "Class", which is the result of the method in that case.

Parameters:

object - the object for which to get the simple class name; may be null

Returns:

the simple class name or the empty string in case the argument is null

Since:

3.7

See Also:

Class.getSimpleName()

getSimpleName

public static java.lang.String getSimpleName(java.lang.Object object,
                                             java.lang.String valueIfNull)

Null-safe version of object.getClass().getSimpleName()

Parameters:

object - the object for which to get the simple class name; may be null

valueIfNull - the value to return if object is null

Returns:

the simple class name or valueIfNull if the argument object is null

Since:

3.0

See Also:

Class.getSimpleName()

hierarchy

public static java.lang.Iterable<java.lang.Class<?>> hierarchy(java.lang.Class<?> type)

Gets an Iterable that can iterate over a class hierarchy in ascending (subclass to superclass) order, excluding interfaces.

Parameters:

type - the type to get the class hierarchy from

Returns:

Iterable an Iterable over the class hierarchy of the given class

Since:

3.2

hierarchy

public static java.lang.Iterable<java.lang.Class<?>> hierarchy(java.lang.Class<?> type,
                                                               ClassUtils.Interfaces interfacesBehavior)

Gets an Iterable that can iterate over a class hierarchy in ascending (subclass to superclass) order.

Parameters:

type - the type to get the class hierarchy from

interfacesBehavior - switch indicating whether to include or exclude interfaces

Returns:

Iterable an Iterable over the class hierarchy of the given class

Since:

3.2

isAssignable

public static boolean isAssignable(java.lang.Class<?> cls,
                                   java.lang.Class<?> toClass)

Checks if one Class can be assigned to a variable of another Class.

Unlike the Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this 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.

Parameters:

cls - the Class to check, may be null

toClass - the Class to try to assign into, returns false if null

Returns:

true if assignment possible

isAssignable

public static boolean isAssignable(java.lang.Class<?> cls,
                                   java.lang.Class<?> toClass,
                                   boolean autoboxing)

Checks if one Class can be assigned to a variable of another Class.

Unlike the Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this 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.

Parameters:

cls - the Class to check, may be null

toClass - the Class to try to assign into, returns false if null

autoboxing - whether to use implicit autoboxing/unboxing between primitives and wrappers

Returns:

true if assignment possible

isAssignable

public static boolean isAssignable(java.lang.Class<?>[] classArray,
                                   java.lang.Class<?>... toClassArray)

Checks if an array of Classes can be assigned to another array of Classes.

This method calls 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 Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this 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.

Parameters:

classArray - the array of Classes to check, may be null

toClassArray - the array of Classes to try to assign into, may be null

Returns:

true if assignment possible

isAssignable

public static boolean isAssignable(java.lang.Class<?>[] classArray,
                                   java.lang.Class<?>[] toClassArray,
                                   boolean autoboxing)

Checks if an array of Classes can be assigned to another array of Classes.

This method calls 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 Class.isAssignableFrom(java.lang.Class) method, this method takes into account widenings of primitive classes and nulls.

Primitive widenings allow an int to be assigned to a long, float or double. This method returns the correct result for these cases.

null may be assigned to any reference type. This method will return true if null is passed in and the toClass is non-primitive.

Specifically, this method tests whether the type represented by the specified Class parameter can be converted to the type represented by this 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.

Parameters:

classArray - the array of Classes to check, may be null

toClassArray - the array of Classes to try to assign into, may be null

autoboxing - whether to use implicit autoboxing/unboxing between primitives and wrappers

Returns:

true if assignment possible

isInnerClass

public static boolean isInnerClass(java.lang.Class<?> cls)

Is the specified class an inner class or static nested class.

Parameters:

cls - the class to check, may be null

Returns:

true if the class is an inner or static nested class, false if not or null

isPublic

public static boolean isPublic(java.lang.Class<?> cls)

Tests whether a Class is public.

Parameters:

cls - Class to test.

Returns:

true if cls is public.

Since:

3.13.0

isPrimitiveOrWrapper

public static boolean isPrimitiveOrWrapper(java.lang.Class<?> type)

Returns whether the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Parameters:

type - The class to query or null.

Returns:

true if the given type is a primitive or primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Since:

3.1

isPrimitiveWrapper

public static boolean isPrimitiveWrapper(java.lang.Class<?> type)

Returns whether the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Parameters:

type - The class to query or null.

Returns:

true if the given type is a primitive wrapper (Boolean, Byte, Character, Short, Integer, Long, Double, Float).

Since:

3.1

primitivesToWrappers

public static java.lang.Class<?>[] primitivesToWrappers(java.lang.Class<?>... classes)

Converts the specified array of primitive Class objects to an array of its corresponding wrapper Class objects.

Parameters:

classes - the class array to convert, may be null or empty

Returns:

an array which contains for each given class, the wrapper class or the original class if class is not a primitive. null if null input. Empty array if an empty array passed in.

Since:

2.1

primitiveToWrapper

public static java.lang.Class<?> primitiveToWrapper(java.lang.Class<?> cls)

Converts the specified primitive Class object to its corresponding wrapper Class object.

NOTE: From v2.2, this method handles Void.TYPE, returning Void.TYPE.

Parameters:

cls - the class to convert, may be null

Returns:

the wrapper class for cls or cls if cls is not a primitive. null if null input.

Since:

2.1

toClass

public static java.lang.Class<?>[] toClass(java.lang.Object... array)

Converts an array of Object in to an array of Class objects. If any of these objects is null, a null element will be inserted into the array.

This method returns null for a null input array.

Parameters:

array - an Object array

Returns:

a Class array, null if null array input

Since:

2.4

wrappersToPrimitives

public static java.lang.Class<?>[] wrappersToPrimitives(java.lang.Class<?>... classes)

Converts the specified array of wrapper Class objects to an array of its corresponding primitive Class objects.

This method invokes wrapperToPrimitive() for each element of the passed in array.

Parameters:

classes - the class array to convert, may be null or empty

Returns:

an array which contains for each given class, the primitive class or null if the original class is not a wrapper class. null if null input. Empty array if an empty array passed in.

Since:

2.4

See Also:

wrapperToPrimitive(Class)

wrapperToPrimitive

public static java.lang.Class<?> wrapperToPrimitive(java.lang.Class<?> cls)

Converts the specified wrapper class to its corresponding primitive class.

This method is the counter part of primitiveToWrapper(). If the passed in class is a wrapper class for a primitive type, this primitive type will be returned (e.g. Integer.TYPE for Integer.class). For other classes, or if the parameter is null, the return value is null.

Parameters:

cls - the class to convert, may be null

Returns:

the corresponding primitive type if cls is a wrapper class, null otherwise

Since:

2.4

See Also:

primitiveToWrapper(Class)