java.lang.reflect

Class AccessibleObject

Inhoudsopgave
  • All Implemented Interfaces:
    AnnotatedElement
    Direct Known Subclasses:
    Constructor, Field, Method

    public class AccessibleObject
extends Object
implements AnnotatedElement
    The AccessibleObject class is the base class for Field, Method and Constructor objects. It provides the ability to flag a reflected object as suppressing default Java language access control checks when it is used. The access checks--for public, default (package) access, protected, and private members--are performed when Fields, Methods or Constructors are used to set or get fields, to invoke methods, or to create and initialize new instances of classes, respectively.

    Setting the accessible flag in a reflected object permits sophisticated applications with sufficient privilege, such as Java Object Serialization or other persistence mechanisms, to manipulate objects in a manner that would normally be prohibited.

    By default, a reflected object is not accessible.

    Since:
    1.2
    See Also:
    Field, Method, Constructor, ReflectPermission

    • Constructor Detail

      • AccessibleObject

        protected AccessibleObject()
        Constructor: only used by the Java Virtual Machine.

    • Method Detail

      • setAccessible

        public static void setAccessible(AccessibleObject[] array,
                 boolean flag)
                          throws SecurityException
        Convenience method to set the accessible flag for an array of objects with a single security check (for efficiency).

        First, if there is a security manager, its checkPermission method is called with a ReflectPermission("suppressAccessChecks") permission.

        A SecurityException is raised if flag is true but accessibility of any of the elements of the input array may not be changed (for example, if the element object is a Constructor object for the class Class). In the event of such a SecurityException, the accessibility of objects is set to flag for array elements upto (and excluding) the element for which the exception occurred; the accessibility of elements beyond (and including) the element for which the exception occurred is unchanged.

        Parameters:
        array - the array of AccessibleObjects
        flag - the new value for the accessible flag in each object
        Throws:
        SecurityException - if the request is denied.
        See Also:
        SecurityManager.checkPermission(java.security.Permission), RuntimePermission

      • setAccessible

        public void setAccessible(boolean flag)
                   throws SecurityException
        Set the accessible flag for this object to the indicated boolean value. A value of true indicates that the reflected object should suppress Java language access checking when it is used. A value of false indicates that the reflected object should enforce Java language access checks.

        First, if there is a security manager, its checkPermission method is called with a ReflectPermission("suppressAccessChecks") permission.

        A SecurityException is raised if flag is true but accessibility of this object may not be changed (for example, if this element object is a Constructor object for the class Class).

        A SecurityException is raised if this object is a Constructor object for the class java.lang.Class, and flag is true.

        Parameters:
        flag - the new value for the accessible flag
        Throws:
        SecurityException - if the request is denied.
        See Also:
        SecurityManager.checkPermission(java.security.Permission), RuntimePermission

      • isAccessible

        public boolean isAccessible()
        Get the value of the accessible flag for this object.
        Returns:
        the value of the object's accessible flag

      • getAnnotation

        public <T extends Annotation> T getAnnotation(Class<T> annotationClass)
        Description copied from interface: AnnotatedElement
        Returns this element's annotation for the specified type if such an annotation is present, else null.
        Specified by:
        getAnnotation in interface AnnotatedElement
        Parameters:
        annotationClass - the Class object corresponding to the annotation type
        Returns:
        this element's annotation for the specified annotation type if present on this element, else null
        Throws:
        NullPointerException - if the given annotation class is null
        Since:
        1.5

      • isAnnotationPresent

        public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass)
        Description copied from interface: AnnotatedElement
        Returns true if an annotation for the specified type is present on this element, else false. This method is designed primarily for convenient access to marker annotations.
        Specified by:
        isAnnotationPresent in interface AnnotatedElement
        Parameters:
        annotationClass - the Class object corresponding to the annotation type
        Returns:
        true if an annotation for the specified annotation type is present on this element, else false
        Throws:
        NullPointerException - if the given annotation class is null
        Since:
        1.5

      • getAnnotations

        public Annotation[] getAnnotations()
        Description copied from interface: AnnotatedElement
        Returns all annotations present on this element. (Returns an array of length zero if this element has no annotations.) The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
        Specified by:
        getAnnotations in interface AnnotatedElement
        Returns:
        all annotations present on this element
        Since:
        1.5

      • getDeclaredAnnotations

        public Annotation[] getDeclaredAnnotations()
        Description copied from interface: AnnotatedElement
        Returns all annotations that are directly present on this element. Unlike the other methods in this interface, this method ignores inherited annotations. (Returns an array of length zero if no annotations are directly present on this element.) The caller of this method is free to modify the returned array; it will have no effect on the arrays returned to other callers.
        Specified by:
        getDeclaredAnnotations in interface AnnotatedElement
        Returns:
        All annotations directly present on this element
        Since:
        1.5

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Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
Bron van het afgedrukte document:https://www.gaudry.be/nl/java-api-rf-java/lang/reflect/accessibleobject.html

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