Class AccessibleObject

All Implemented Interfaces:
AnnotatedElement
Direct Known Subclasses:
Executable, Field 

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

Constructors

Modifier Constructor and Description
protected AccessibleObject()

Constructor: only used by the Java Virtual Machine.

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 annotations that are present on this element.
<T extends Annotation>
T[]		 getAnnotationsByType(Class<T> annotationClass)

Returns annotations that are associated with this element.
<T extends Annotation>
T		 getDeclaredAnnotation(Class<T> annotationClass)

Returns this element's annotation for the specified type if such an annotation is directly present, else null.
Annotation[] getDeclaredAnnotations()

Returns annotations that are directly present on this element.
<T extends Annotation>
T[]		 getDeclaredAnnotationsByType(Class<T> annotationClass)

Returns this element's annotation(s) for the specified type if such annotations are either directly present or indirectly present.
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

Constructors

AccessibleObject

protected AccessibleObject()

Constructor: only used by the Java Virtual Machine.

Methods

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
Type Parameters:
T - the type of the annotation to query for and return if present
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)

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.

The truth value returned by this method is equivalent to: getAnnotation(annotationClass) != null

The body of the default method is specified to be the code above.

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

getAnnotationsByType

public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass)

Description copied from interface: AnnotatedElement

Returns annotations that are associated with this element. If there are no annotations associated with this element, the return value is an array of length 0. The difference between this method and AnnotatedElement.getAnnotation(Class) is that this method detects if its argument is a repeatable annotation type (JLS 9.6), and if so, attempts to find one or more annotations of that type by "looking through" a container annotation. 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:
getAnnotationsByType in interface AnnotatedElement
Type Parameters:
T - the type of the annotation to query for and return if present
Parameters:
annotationClass - the Class object corresponding to the annotation type
Returns:
all this element's annotations for the specified annotation type if associated with this element, else an array of length zero
Throws:
NullPointerException - if the given annotation class is null
Since:
1.8

getAnnotations

public Annotation[] getAnnotations()

Description copied from interface: AnnotatedElement

Returns annotations that are present on this element. If there are no annotations present on this element, the return value is an array of length 0. 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:
annotations present on this element
Since:
1.5

getDeclaredAnnotation

public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass)

Description copied from interface: AnnotatedElement

Returns this element's annotation for the specified type if such an annotation is directly present, else null. This method ignores inherited annotations. (Returns null if no annotations are directly present on this element.)

Specified by:
getDeclaredAnnotation in interface AnnotatedElement
Type Parameters:
T - the type of the annotation to query for and return if directly present
Parameters:
annotationClass - the Class object corresponding to the annotation type
Returns:
this element's annotation for the specified annotation type if directly present on this element, else null
Throws:
NullPointerException - if the given annotation class is null
Since:
1.8

getDeclaredAnnotationsByType

public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass)

Description copied from interface: AnnotatedElement

Returns this element's annotation(s) for the specified type if such annotations are either directly present or indirectly present. This method ignores inherited annotations. If there are no specified annotations directly or indirectly present on this element, the return value is an array of length 0. The difference between this method and AnnotatedElement.getDeclaredAnnotation(Class) is that this method detects if its argument is a repeatable annotation type (JLS 9.6), and if so, attempts to find one or more annotations of that type by "looking through" a container annotation if one is present. 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:
getDeclaredAnnotationsByType in interface AnnotatedElement
Type Parameters:
T - the type of the annotation to query for and return if directly or indirectly present
Parameters:
annotationClass - the Class object corresponding to the annotation type
Returns:
all this element's annotations for the specified annotation type if directly or indirectly present on this element, else an array of length zero
Throws:
NullPointerException - if the given annotation class is null
Since:
1.8

getDeclaredAnnotations

public Annotation[] getDeclaredAnnotations()

Description copied from interface: AnnotatedElement

Returns annotations that are directly present on this element. This method ignores inherited annotations. If there are no annotations directly present on this element, the return value is an array of length 0. 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:
annotations directly present on this element
Since:
1.5

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https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/AccessibleObject.html