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
.
Modifier and Type | Class and Description |
---|---|
static class |
ClassUtils.Interfaces
Inclusivity literals for
hierarchy(Class, Interfaces) . |
Modifier and Type | Field and Description |
---|---|
private static java.util.Map<java.lang.String,java.lang.String> |
abbreviationMap
Maps a primitive class name to its corresponding abbreviation used in array class names.
|
static java.lang.String |
INNER_CLASS_SEPARATOR
The inner class separator String:
"$" . |
static char |
INNER_CLASS_SEPARATOR_CHAR
The inner class separator character:
'$' == {@value} . |
private static java.util.Map<java.lang.String,java.lang.Class<?>> |
namePrimitiveMap
Maps names of primitives to their corresponding primitive
Class es. |
static java.lang.String |
PACKAGE_SEPARATOR
The package separator String:
"." . |
static char |
PACKAGE_SEPARATOR_CHAR
The package separator character:
'.' == {@value} . |
private static java.util.Map<java.lang.Class<?>,java.lang.Class<?>> |
primitiveWrapperMap
Maps primitive
Class es to their corresponding wrapper Class . |
private static java.util.Map<java.lang.String,java.lang.String> |
reverseAbbreviationMap
Maps an abbreviation used in array class names to corresponding primitive class name.
|
private static java.util.Map<java.lang.Class<?>,java.lang.Class<?>> |
wrapperPrimitiveMap
Maps wrapper
Class es to their corresponding primitive types. |
Constructor and Description |
---|
ClassUtils()
ClassUtils instances should NOT be constructed in standard programming.
|
Modifier and Type | Method and Description |
---|---|
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. |
private static void |
getAllInterfaces(java.lang.Class<?> cls,
java.util.HashSet<java.lang.Class<?>> interfacesFound)
Gets the interfaces for the specified class.
|
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 . |
private static java.lang.String |
getCanonicalName(java.lang.String className)
Converts a given name of class into canonical format.
|
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 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 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.
|
private static java.lang.String |
toCanonicalName(java.lang.String className)
Converts a class name to a JLS style class name.
|
static java.lang.Class<?>[] |
toClass(java.lang.Object... array)
Converts an array of
Object in to an array of Class objects. |
private static boolean |
useFull(int runAheadTarget,
int source,
int originalLength,
int desiredLength)
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.
|
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.
|
public static final char PACKAGE_SEPARATOR_CHAR
'.' == {@value}
.public static final java.lang.String PACKAGE_SEPARATOR
"."
.public static final char INNER_CLASS_SEPARATOR_CHAR
'$' == {@value}
.public static final java.lang.String INNER_CLASS_SEPARATOR
"$"
.private static final java.util.Map<java.lang.String,java.lang.Class<?>> namePrimitiveMap
Class
es.private static final java.util.Map<java.lang.Class<?>,java.lang.Class<?>> primitiveWrapperMap
Class
es to their corresponding wrapper Class
.private static final java.util.Map<java.lang.Class<?>,java.lang.Class<?>> wrapperPrimitiveMap
Class
es to their corresponding primitive types.private static final java.util.Map<java.lang.String,java.lang.String> abbreviationMap
private static final java.util.Map<java.lang.String,java.lang.String> reverseAbbreviationMap
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.
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).
object
- the class to get the short name for, may be null
valueIfNull
- the value to return if the object is null
valueIfNull
if the argument object
is null
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.
cls
- the class to get the short name for..
(dot) character.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.
className
- the className to get the short name for. It has to be formatted as returned by
Class.getName()
and not Class.getCanonicalName()
.
(dot) character.public static java.lang.String getSimpleName(java.lang.Class<?> cls)
Null-safe version of cls.getSimpleName()
cls
- the class for which to get the simple name; may be nullnull
Class.getSimpleName()
public static java.lang.String getSimpleName(java.lang.Class<?> cls, java.lang.String valueIfNull)
Null-safe version of cls.getSimpleName()
cls
- the class for which to get the simple name; may be nullvalueIfNull
- the value to return if nullvalueIfNull
if the
argument cls
is null
Class.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.
object
- the object for which to get the simple class name; may be nullnull
Class.getSimpleName()
public static java.lang.String getSimpleName(java.lang.Object object, java.lang.String valueIfNull)
Null-safe version of object.getClass().getSimpleName()
object
- the object for which to get the simple class name; may be nullvalueIfNull
- the value to return if object
is null
valueIfNull
if the
argument object
is null
Class.getSimpleName()
public static java.lang.String getName(java.lang.Class<?> cls)
Null-safe version of cls.getName()
cls
- the class for which to get the class name; may be nullnull
Class.getSimpleName()
public static java.lang.String getName(java.lang.Class<?> cls, java.lang.String valueIfNull)
Null-safe version of cls.getName()
cls
- the class for which to get the class name; may be nullvalueIfNull
- the return value if the argument cls
is null
valueIfNull
Class.getName()
public static java.lang.String getName(java.lang.Object object)
Null-safe version of object.getClass().getName()
object
- the object for which to get the class name; may be nullClass.getSimpleName()
public static java.lang.String getName(java.lang.Object object, java.lang.String valueIfNull)
Null-safe version of object.getClass().getSimpleName()
object
- the object for which to get the class name; may be nullvalueIfNull
- the value to return if object
is null
valueIfNull
Class.getName()
public static java.lang.String getPackageName(java.lang.Object object, java.lang.String valueIfNull)
Gets the package name of an Object
.
object
- the class to get the package name for, may be nullvalueIfNull
- the value to return if nullpublic static java.lang.String getPackageName(java.lang.Class<?> cls)
Gets the package name of a Class
.
cls
- the class to get the package name for, may be null
.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.
className
- the className to get the package name for, may be null
public static java.lang.String getAbbreviatedName(java.lang.Class<?> cls, int lengthHint)
Gets the abbreviated name of a Class
.
cls
- the class to get the abbreviated name for, may be null
lengthHint
- the desired length of the abbreviated namejava.lang.IllegalArgumentException
- if len <= 0getAbbreviatedName(String, int)
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
.
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" |
className
- the className to get the abbreviated name for, may be null
lengthHint
- the desired length of the abbreviated namenull
or empty string. The abbreviated name may be
longer than the desired length if it cannot be abbreviated to the desired length.java.lang.IllegalArgumentException
- if len <= 0
private static boolean useFull(int runAheadTarget, int source, int originalLength, int desiredLength)
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 source
index, from where the characters are copied points one position
after the last character, a.k.a. 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.
runAheadTarget
- the target index (where the characters were
copied to) pointing after the last character
copied when the current part was copiedsource
- the source index (where the characters were
copied from) pointing after the last
character copied when the current part was
copiedoriginalLength
- the original length of the class full name,
which is abbreviateddesiredLength
- the desired length of the abbreviated class
nametrue
if it can be kept in its original length
false
if the current part has to be abbreviated andpublic static java.util.List<java.lang.Class<?>> getAllSuperclasses(java.lang.Class<?> cls)
Gets a List
of superclasses for the given class.
cls
- the class to look up, may be null
List
of superclasses in order going up from this one
null
if null inputpublic 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.
cls
- the class to look up, may be null
List
of interfaces in order,
null
if null inputprivate static void getAllInterfaces(java.lang.Class<?> cls, java.util.HashSet<java.lang.Class<?>> interfacesFound)
cls
- the class to look up, may be null
interfacesFound
- the Set
of interfaces for the classpublic 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
.
classNames
- the classNames to changeList
of Class objects corresponding to the class names,
null
if null inputjava.lang.ClassCastException
- if classNames contains a non String entrypublic 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
.
classes
- the classes to changeList
of class names corresponding to the Class objects,
null
if null inputjava.lang.ClassCastException
- if classes
contains a non-Class
entrypublic 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
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.
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.
classArray
- the array of Classes to check, may be null
toClassArray
- the array of Classes to try to assign into, may be null
true
if assignment possiblepublic 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
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.
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.
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 wrapperstrue
if assignment possiblepublic static boolean isPrimitiveOrWrapper(java.lang.Class<?> type)
type
is a primitive or primitive wrapper (Boolean
, Byte
, Character
,
Short
, Integer
, Long
, Double
, Float
).type
- The class to query or null.type
is a primitive or primitive wrapper (Boolean
, Byte
, Character
,
Short
, Integer
, Long
, Double
, Float
).public static boolean isPrimitiveWrapper(java.lang.Class<?> type)
type
is a primitive wrapper (Boolean
, Byte
, Character
, Short
,
Integer
, Long
, Double
, Float
).type
- The class to query or null.type
is a primitive wrapper (Boolean
, Byte
, Character
, Short
,
Integer
, Long
, Double
, Float
).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
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.
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.
cls
- the Class to check, may be nulltoClass
- the Class to try to assign into, returns false if nulltrue
if assignment possiblepublic 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
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.
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.
cls
- the Class to check, may be nulltoClass
- the Class to try to assign into, returns false if nullautoboxing
- whether to use implicit autoboxing/unboxing between primitives and wrapperstrue
if assignment possiblepublic 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
.
cls
- the class to convert, may be nullcls
or cls
if
cls
is not a primitive. null
if null input.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.
classes
- the class array to convert, may be null or emptynull
if null input.
Empty array if an empty array passed in.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.
cls
- the class to convert, may be nullcls
is a
wrapper class, null otherwiseprimitiveToWrapper(Class)
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.
classes
- the class array to convert, may be null or emptynull
if null input.
Empty array if an empty array passed in.wrapperToPrimitive(Class)
public static boolean isInnerClass(java.lang.Class<?> cls)
Is the specified class an inner class or static nested class.
cls
- the class to check, may be nulltrue
if the class is an inner or static nested class,
false if not or null
public static java.lang.Class<?> getClass(java.lang.ClassLoader classLoader, java.lang.String className, boolean initialize) throws java.lang.ClassNotFoundException
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;
".classLoader
- the class loader to use to load the classclassName
- the class nameinitialize
- whether the class must be initializedclassName
using the classLoader
java.lang.ClassNotFoundException
- if the class is not foundpublic static java.lang.Class<?> getClass(java.lang.ClassLoader classLoader, java.lang.String className) throws java.lang.ClassNotFoundException
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;
".classLoader
- the class loader to use to load the classclassName
- the class nameclassName
using the classLoader
java.lang.ClassNotFoundException
- if the class is not foundpublic static java.lang.Class<?> getClass(java.lang.String className) throws java.lang.ClassNotFoundException
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;
".className
- the class nameclassName
using the current thread's context class loaderjava.lang.ClassNotFoundException
- if the class is not foundpublic static java.lang.Class<?> getClass(java.lang.String className, boolean initialize) throws java.lang.ClassNotFoundException
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;
".className
- the class nameinitialize
- whether the class must be initializedclassName
using the current thread's context class loaderjava.lang.ClassNotFoundException
- if the class is not foundpublic 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[]);
cls
- the class to check, not nullmethodName
- the name of the methodparameterTypes
- the list of parametersjava.lang.NullPointerException
- if the class is nulljava.lang.SecurityException
- if a security violation occurredjava.lang.NoSuchMethodException
- if the method is not found in the given class
or if the method doesn't conform with the requirementsprivate static java.lang.String toCanonicalName(java.lang.String className)
className
- the class namepublic 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.
array
- an Object
arrayClass
array, null
if null array inputpublic static java.lang.String getShortCanonicalName(java.lang.Object object, java.lang.String valueIfNull)
Gets the canonical name minus the package name for an Object
.
object
- the class to get the short name for, may be nullvalueIfNull
- the value to return if nullpublic static java.lang.String getCanonicalName(java.lang.Class<?> cls)
Gets the canonical class name for a Class
.
cls
- the class for which to get the canonical class name; may be nullClass.getCanonicalName()
public static java.lang.String getCanonicalName(java.lang.Class<?> cls, java.lang.String valueIfNull)
Gets the canonical name for a Class
.
cls
- the class for which to get the canonical class name; may be nullvalueIfNull
- the return value if nullvalueIfNull
Class.getCanonicalName()
public static java.lang.String getCanonicalName(java.lang.Object object)
Gets the canonical name for an Object
.
object
- the object for which to get the canonical class name; may be nullClass.getCanonicalName()
public static java.lang.String getCanonicalName(java.lang.Object object, java.lang.String valueIfNull)
Gets the canonical name for an Object
.
object
- the object for which to get the canonical class name; may be nullvalueIfNull
- the return value if nullvalueIfNull
Class.getCanonicalName()
public static java.lang.String getShortCanonicalName(java.lang.Class<?> cls)
Gets the canonical name minus the package name from a Class
.
cls
- the class for which to get the short canonical class name; may be nullpublic 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.
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[][]" |
canonicalName
- the class name to get the short name forpublic static java.lang.String getPackageCanonicalName(java.lang.Object object, java.lang.String valueIfNull)
Gets the package name from the class name of an Object
.
object
- the class to get the package name for, may be nullvalueIfNull
- the value to return if nullpublic static java.lang.String getPackageCanonicalName(java.lang.Class<?> cls)
Gets the package name from the canonical name of a Class
.
cls
- the class to get the package name for, may be null
.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.
name
- the name to get the package name for, may be null
private static java.lang.String getCanonicalName(java.lang.String className)
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 $
separators in case
the class is inner class.
Example:
getCanonicalName("[I") = "int[]"
getCanonicalName("[Ljava.lang.String;") = "java.lang.String[]"
getCanonicalName("java.lang.String") = "java.lang.String"
className
- the name of classpublic static java.lang.Iterable<java.lang.Class<?>> hierarchy(java.lang.Class<?> type)
Iterable
that can iterate over a class hierarchy in ascending (subclass to superclass) order,
excluding interfaces.type
- the type to get the class hierarchy frompublic static java.lang.Iterable<java.lang.Class<?>> hierarchy(java.lang.Class<?> type, ClassUtils.Interfaces interfacesBehavior)
Iterable
that can iterate over a class hierarchy in ascending (subclass to superclass) order.type
- the type to get the class hierarchy frominterfacesBehavior
- switch indicating whether to include or exclude interfaces