Class ClassUtil


  • public final class ClassUtil
    extends java.lang.Object
    • Constructor Summary

      Constructors 
      Constructor Description
      ClassUtil()  
    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static java.lang.String canBeABeanType​(java.lang.Class<?> type)  
      static void checkAndFixAccess​(java.lang.reflect.Member member)
      Method called to check if we can use the passed method or constructor (wrt access restriction -- public methods can be called, others usually not); and if not, if there is a work-around for the problem.
      static <T> T createInstance​(java.lang.Class<T> cls, boolean canFixAccess)
      Method that can be called to try to create an instantiate of specified type.
      static java.lang.Object defaultValue​(java.lang.Class<?> cls)
      Helper method used to get default value for wrappers used for primitive types (0 for Integer etc)
      static java.lang.Class<?> findClass​(java.lang.String className)  
      static <T> java.lang.reflect.Constructor<T> findConstructor​(java.lang.Class<T> cls, boolean canFixAccess)  
      static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.lang.Class<?> cls)
      Helper method that can be used to dynamically figure out formal enumeration type (class) for given class of an enumeration value.
      static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.lang.Enum<?> en)
      Helper method that can be used to dynamically figure out formal enumeration type (class) for given enumeration.
      static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.util.EnumMap<?,​?> m)
      Helper method that can be used to dynamically figure out enumeration type of given EnumSet, without having access to its declaration.
      static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.util.EnumSet<?> s)
      Helper method that can be used to dynamically figure out enumeration type of given EnumSet, without having access to its declaration.
      static java.util.List<java.lang.Class<?>> findSuperTypes​(java.lang.Class<?> cls, java.lang.Class<?> endBefore)
      Method that will find all sub-classes and implemented interfaces of a given class or interface.
      static java.util.List<java.lang.Class<?>> findSuperTypes​(java.lang.Class<?> cls, java.lang.Class<?> endBefore, java.util.List<java.lang.Class<?>> result)  
      static java.lang.String getClassDescription​(java.lang.Object classOrInstance)
      Helper method used to construct appropriate description when passed either type (Class) or an instance; in latter case, class of instance is to be used.
      static java.lang.Class<?> getOuterClass​(java.lang.Class<?> type)
      Method for finding enclosing class for non-static inner classes
      static java.lang.Throwable getRootCause​(java.lang.Throwable t)
      Method that can be used to find the "root cause", innermost of chained (wrapped) exceptions.
      static boolean hasGetterSignature​(java.lang.reflect.Method m)  
      static boolean isCollectionMapOrArray​(java.lang.Class<?> type)  
      static boolean isConcrete​(java.lang.Class<?> type)
      Helper method that checks if given class is a concrete one; that is, not an interface or abstract class.
      static boolean isConcrete​(java.lang.reflect.Member member)  
      static java.lang.String isLocalType​(java.lang.Class<?> type)
      Deprecated.
      since 1.9, use variant that takes second argument
      static java.lang.String isLocalType​(java.lang.Class<?> type, boolean allowNonStatic)  
      static boolean isProxyType​(java.lang.Class<?> type)
      Helper method used to weed out dynamic Proxy types; types that do not expose concrete method API that we could use to figure out automatic Bean (property) based serialization.
      static void throwAsIAE​(java.lang.Throwable t)
      Method that will wrap 't' as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      static void throwAsIAE​(java.lang.Throwable t, java.lang.String msg)
      Method that will wrap 't' as an IllegalArgumentException (and with specified message) if it is a checked exception; otherwise (runtime exception or error) throw as is
      static void throwRootCause​(java.lang.Throwable t)
      Method that will unwrap root causes of given Throwable, and throw the innermost Exception or Error as is.
      static void unwrapAndThrowAsIAE​(java.lang.Throwable t)
      Method that will locate the innermost exception for given Throwable; and then wrap it as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      static void unwrapAndThrowAsIAE​(java.lang.Throwable t, java.lang.String msg)
      Method that will locate the innermost exception for given Throwable; and then wrap it as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      static java.lang.Class<?> wrapperType​(java.lang.Class<?> primitiveType)
      Helper method for finding wrapper type for given primitive type (why isn't there one in JDK?)
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ClassUtil

        public ClassUtil()
    • Method Detail

      • findSuperTypes

        public static java.util.List<java.lang.Class<?>> findSuperTypes​(java.lang.Class<?> cls,
                                                                        java.lang.Class<?> endBefore)
        Method that will find all sub-classes and implemented interfaces of a given class or interface. Classes are listed in order of precedence, starting with the immediate super-class, followed by interfaces class directly declares to implemented, and then recursively followed by parent of super-class and so forth. Note that Object.class is not included in the list regardless of whether endBefore argument is defined or not.
        Parameters:
        endBefore - Super-type to NOT include in results, if any; when encountered, will be ignored (and no super types are checked).
      • findSuperTypes

        public static java.util.List<java.lang.Class<?>> findSuperTypes​(java.lang.Class<?> cls,
                                                                        java.lang.Class<?> endBefore,
                                                                        java.util.List<java.lang.Class<?>> result)
      • canBeABeanType

        public static java.lang.String canBeABeanType​(java.lang.Class<?> type)
        Returns:
        Null if class might be a bean; type String (that identifies why it's not a bean) if not
      • isLocalType

        @Deprecated
        public static java.lang.String isLocalType​(java.lang.Class<?> type)
        Deprecated.
        since 1.9, use variant that takes second argument
      • isLocalType

        public static java.lang.String isLocalType​(java.lang.Class<?> type,
                                                   boolean allowNonStatic)
        Since:
        1.9
      • getOuterClass

        public static java.lang.Class<?> getOuterClass​(java.lang.Class<?> type)
        Method for finding enclosing class for non-static inner classes
        Since:
        1.9
      • isProxyType

        public static boolean isProxyType​(java.lang.Class<?> type)
        Helper method used to weed out dynamic Proxy types; types that do not expose concrete method API that we could use to figure out automatic Bean (property) based serialization.
      • isConcrete

        public static boolean isConcrete​(java.lang.Class<?> type)
        Helper method that checks if given class is a concrete one; that is, not an interface or abstract class.
      • isConcrete

        public static boolean isConcrete​(java.lang.reflect.Member member)
        Since:
        1.6
      • isCollectionMapOrArray

        public static boolean isCollectionMapOrArray​(java.lang.Class<?> type)
      • getClassDescription

        public static java.lang.String getClassDescription​(java.lang.Object classOrInstance)
        Helper method used to construct appropriate description when passed either type (Class) or an instance; in latter case, class of instance is to be used.
      • findClass

        public static java.lang.Class<?> findClass​(java.lang.String className)
                                            throws java.lang.ClassNotFoundException
        Throws:
        java.lang.ClassNotFoundException
      • hasGetterSignature

        public static boolean hasGetterSignature​(java.lang.reflect.Method m)
      • getRootCause

        public static java.lang.Throwable getRootCause​(java.lang.Throwable t)
        Method that can be used to find the "root cause", innermost of chained (wrapped) exceptions.
      • throwRootCause

        public static void throwRootCause​(java.lang.Throwable t)
                                   throws java.lang.Exception
        Method that will unwrap root causes of given Throwable, and throw the innermost Exception or Error as is. This is useful in cases where mandatory wrapping is added, which is often done by Reflection API.
        Throws:
        java.lang.Exception
        Since:
        1.7
      • throwAsIAE

        public static void throwAsIAE​(java.lang.Throwable t)
        Method that will wrap 't' as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      • throwAsIAE

        public static void throwAsIAE​(java.lang.Throwable t,
                                      java.lang.String msg)
        Method that will wrap 't' as an IllegalArgumentException (and with specified message) if it is a checked exception; otherwise (runtime exception or error) throw as is
      • unwrapAndThrowAsIAE

        public static void unwrapAndThrowAsIAE​(java.lang.Throwable t)
        Method that will locate the innermost exception for given Throwable; and then wrap it as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      • unwrapAndThrowAsIAE

        public static void unwrapAndThrowAsIAE​(java.lang.Throwable t,
                                               java.lang.String msg)
        Method that will locate the innermost exception for given Throwable; and then wrap it as an IllegalArgumentException if it is a checked exception; otherwise (runtime exception or error) throw as is
      • createInstance

        public static <T> T createInstance​(java.lang.Class<T> cls,
                                           boolean canFixAccess)
                                    throws java.lang.IllegalArgumentException
        Method that can be called to try to create an instantiate of specified type. Instantiation is done using default no-argument constructor.
        Parameters:
        canFixAccess - Whether it is possible to try to change access rights of the default constructor (in case it is not publicly accessible) or not.
        Throws:
        java.lang.IllegalArgumentException - If instantiation fails for any reason; except for cases where constructor throws an unchecked exception (which will be passed as is)
      • findConstructor

        public static <T> java.lang.reflect.Constructor<T> findConstructor​(java.lang.Class<T> cls,
                                                                           boolean canFixAccess)
                                                                    throws java.lang.IllegalArgumentException
        Throws:
        java.lang.IllegalArgumentException
      • defaultValue

        public static java.lang.Object defaultValue​(java.lang.Class<?> cls)
        Helper method used to get default value for wrappers used for primitive types (0 for Integer etc)
        Since:
        1.6.1
      • wrapperType

        public static java.lang.Class<?> wrapperType​(java.lang.Class<?> primitiveType)
        Helper method for finding wrapper type for given primitive type (why isn't there one in JDK?)
        Since:
        1.7.1
      • checkAndFixAccess

        public static void checkAndFixAccess​(java.lang.reflect.Member member)
        Method called to check if we can use the passed method or constructor (wrt access restriction -- public methods can be called, others usually not); and if not, if there is a work-around for the problem.
      • findEnumType

        public static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.util.EnumSet<?> s)
        Helper method that can be used to dynamically figure out enumeration type of given EnumSet, without having access to its declaration. Code is needed to work around design flaw in JDK.
        Since:
        1.5
      • findEnumType

        public static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.util.EnumMap<?,​?> m)
        Helper method that can be used to dynamically figure out enumeration type of given EnumSet, without having access to its declaration. Code is needed to work around design flaw in JDK.
        Since:
        1.5
      • findEnumType

        public static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.lang.Enum<?> en)
        Helper method that can be used to dynamically figure out formal enumeration type (class) for given enumeration. This is either class of enum instance (for "simple" enumerations), or its superclass (for enums with instance fields or methods)
      • findEnumType

        public static java.lang.Class<? extends java.lang.Enum<?>> findEnumType​(java.lang.Class<?> cls)
        Helper method that can be used to dynamically figure out formal enumeration type (class) for given class of an enumeration value. This is either class of enum instance (for "simple" enumerations), or its superclass (for enums with instance fields or methods)