java.lang.reflect

Class AccessibleObject

java.lang.Object

java.lang.reflect.AccessibleObject

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 Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
<T extends Annotation> T	getAnnotation(Class<T> annotationClass) Returns this element's annotation for the specified type if such an annotation is present, else null.
Annotation[]	getAnnotations() Returns all annotations present on this element.
Annotation[]	getDeclaredAnnotations() Returns all annotations that are directly present on this element.
boolean	isAccessible() Get the value of the accessible flag for this object.
boolean	isAnnotationPresent(Class<? extends Annotation> annotationClass) Returns true if an annotation for the specified type is present on this element, else false.
static void	setAccessible(AccessibleObject[] array, boolean flag) Convenience method to set the accessible flag for an array of objects with a single security check (for efficiency).
void	setAccessible(boolean flag) Set the accessible flag for this object to the indicated boolean value.

Methods inherited from class java.lang.Object

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

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