Package org.apache.commons.lang3.reflect

Class MemberUtils

  • final class MemberUtils
extends java.lang.Object
    Contains common code for working with Methods/Constructors, extracted and refactored from MethodUtils when it was imported from Commons BeanUtils.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      private static class  MemberUtils.Executable
      A class providing a subset of the API of java.lang.reflect.Executable in Java 1.8, providing a common representation for function signatures for Constructors and Methods.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static int ACCESS_TEST  
      private static java.lang.Class<?>[] WIDENING_PRIMITIVE_TYPES
      Array of primitive number types ordered by "promotability" from narrow to wide.

    • Constructor Summary

      Constructors 
      Constructor Description
      MemberUtils()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      (package private) static int compareConstructorFit​(java.lang.reflect.Constructor<?> left, java.lang.reflect.Constructor<?> right, java.lang.Class<?>[] actual)
      Compares the relative fitness of two Constructors in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
      (package private) static int compareMethodFit​(java.lang.reflect.Method left, java.lang.reflect.Method right, java.lang.Class<?>[] actual)
      Compares the relative fitness of two Methods in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
      private static int compareParameterTypes​(MemberUtils.Executable left, MemberUtils.Executable right, java.lang.Class<?>[] actual)
      Compares the relative fitness of two Executables in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
      private static float getObjectTransformationCost​(java.lang.Class<?> srcClass, java.lang.Class<?> destClass)
      Gets the number of steps needed to turn the source class into the destination class.
      private static float getPrimitivePromotionCost​(java.lang.Class<?> srcClass, java.lang.Class<?> destClass)
      Gets the number of steps required to promote a primitive to another type.
      private static float getTotalTransformationCost​(java.lang.Class<?>[] srcArgs, MemberUtils.Executable executable)
      Gets the sum of the object transformation cost for each class in the source argument list.
      (package private) static boolean isAccessible​(java.lang.reflect.Member member)
      Tests whether a Member is accessible.
      (package private) static boolean isMatchingConstructor​(java.lang.reflect.Constructor<?> method, java.lang.Class<?>[] parameterTypes)  
      private static boolean isMatchingExecutable​(MemberUtils.Executable method, java.lang.Class<?>[] parameterTypes)  
      (package private) static boolean isMatchingMethod​(java.lang.reflect.Method method, java.lang.Class<?>[] parameterTypes)  
      (package private) static boolean isPackage​(int modifiers)
      Tests whether a given set of modifiers implies package access.
      (package private) static boolean isPublic​(java.lang.reflect.Member member)
      Tests whether a Member is public.
      (package private) static boolean isStatic​(java.lang.reflect.Member member)
      Tests whether a Member is static.
      (package private) static <T extends java.lang.reflect.AccessibleObject>
      T      		 setAccessibleWorkaround​(T obj)
      Default access superclass workaround.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • WIDENING_PRIMITIVE_TYPES

        private static final java.lang.Class<?>[] WIDENING_PRIMITIVE_TYPES
        Array of primitive number types ordered by "promotability" from narrow to wide.

    • Constructor Detail

      • MemberUtils

        MemberUtils()

    • Method Detail

      • compareConstructorFit

        static int compareConstructorFit​(java.lang.reflect.Constructor<?> left,
                                 java.lang.reflect.Constructor<?> right,
                                 java.lang.Class<?>[] actual)
        Compares the relative fitness of two Constructors in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
        Parameters:
        left - the "left" Constructor.
        right - the "right" Constructor.
        actual - the runtime parameter types to match against. left/right.
        Returns:
        int consistent with compare semantics.

      • compareMethodFit

        static int compareMethodFit​(java.lang.reflect.Method left,
                            java.lang.reflect.Method right,
                            java.lang.Class<?>[] actual)
        Compares the relative fitness of two Methods in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
        Parameters:
        left - the "left" Method.
        right - the "right" Method.
        actual - the runtime parameter types to match against. left/right.
        Returns:
        int consistent with compare semantics.

      • compareParameterTypes

        private static int compareParameterTypes​(MemberUtils.Executable left,
                                         MemberUtils.Executable right,
                                         java.lang.Class<?>[] actual)
        Compares the relative fitness of two Executables in terms of how well they match a set of runtime parameter types, such that a list ordered by the results of the comparison would return the best match first (least).
        Parameters:
        left - the "left" Executable.
        right - the "right" Executable.
        actual - the runtime parameter types to match against. left/right.
        Returns:
        int consistent with compare semantics.

      • getObjectTransformationCost

        private static float getObjectTransformationCost​(java.lang.Class<?> srcClass,
                                                 java.lang.Class<?> destClass)
        Gets the number of steps needed to turn the source class into the destination class. This represents the number of steps in the object hierarchy graph.
        Parameters:
        srcClass - The source class.
        destClass - The destination class.
        Returns:
        The cost of transforming an object.

      • getPrimitivePromotionCost

        private static float getPrimitivePromotionCost​(java.lang.Class<?> srcClass,
                                               java.lang.Class<?> destClass)
        Gets the number of steps required to promote a primitive to another type.
        Parameters:
        srcClass - the (primitive) source class.
        destClass - the (primitive) destination class.
        Returns:
        The cost of promoting the primitive.

      • getTotalTransformationCost

        private static float getTotalTransformationCost​(java.lang.Class<?>[] srcArgs,
                                                MemberUtils.Executable executable)
        Gets the sum of the object transformation cost for each class in the source argument list.
        Parameters:
        srcArgs - The source arguments.
        executable - The executable to calculate transformation costs for.
        Returns:
        The total transformation cost.

      • isAccessible

        static boolean isAccessible​(java.lang.reflect.Member member)
        Tests whether a Member is accessible.
        Parameters:
        member - Member to test, may be null.
        Returns:
        true if m is accessible.

      • isMatchingConstructor

        static boolean isMatchingConstructor​(java.lang.reflect.Constructor<?> method,
                                     java.lang.Class<?>[] parameterTypes)

      • isMatchingExecutable

        private static boolean isMatchingExecutable​(MemberUtils.Executable method,
                                            java.lang.Class<?>[] parameterTypes)

      • isMatchingMethod

        static boolean isMatchingMethod​(java.lang.reflect.Method method,
                                java.lang.Class<?>[] parameterTypes)

      • isPackage

        static boolean isPackage​(int modifiers)
        Tests whether a given set of modifiers implies package access.
        Parameters:
        modifiers - to test.
        Returns:
        true unless package/protected/private modifier detected

      • isPublic

        static boolean isPublic​(java.lang.reflect.Member member)
        Tests whether a Member is public.
        Parameters:
        member - Member to test, may be null.
        Returns:
        true if m is public.

      • isStatic

        static boolean isStatic​(java.lang.reflect.Member member)
        Tests whether a Member is static.
        Parameters:
        member - Member to test, may be null.
        Returns:
        true if m is static.

      • setAccessibleWorkaround

        static <T extends java.lang.reflect.AccessibleObject> T setAccessibleWorkaround​(T obj)
        Default access superclass workaround.

        When a public class has a default access superclass with public members, these members are accessible. Calling them from compiled code works fine. Unfortunately, on some JVMs, using reflection to invoke these members seems to (wrongly) prevent access even when the modifier is public. Calling setAccessible(true) solves the problem but will only work from sufficiently privileged code. Better workarounds would be gratefully accepted.

        Parameters:
        obj - the AccessibleObject to set as accessible, may be null.
        Returns:
        a boolean indicating whether the accessibility of the object was set to true.