* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.

 * The {@code AccessibleObject} class is the base class for {@code Field},

 * {@code Method}, and {@code Constructor} objects (known as <em>reflected

 * objects</em>). It provides the ability to flag a reflected object as

 * suppressing checks for Java language access control when it is used. This

 * 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.

 * <p> Java language access control prevents use of private members outside

 * their class; package access members outside their package; protected members

 * outside their package or subclasses; and public members outside their

 * module unless they are declared in an {@link Module#isExported(String,Module)

 * exported} package and the user {@link Module#canRead reads} their module. By

 * default, Java language access control is enforced (with one variation) when

 * {@code Field}s, {@code Method}s, or {@code Constructor}s are used to get or

 * set fields, to invoke methods, or to create and initialize new instances of

 * classes, respectively. Every reflected object checks that the code using it

 * is in an appropriate class, package, or module. </p>

 * <p> The one variation from Java language access control is that the checks

 * by reflected objects assume readability. That is, the module containing

 * the use of a reflected object is assumed to read the module in which

 * the underlying field, method, or constructor is declared. </p>

 * <p> Whether the checks for Java language access control can be suppressed

 * (and thus, whether access can be enabled) depends on whether the reflected

 * object corresponds to a member in an exported or open package

 * (see {@link #setAccessible(boolean)}). </p>

 *

 * @jls 6.6 Access Control

 * @revised 9

 * @spec JPMS

     * array of reflected objects with a single security check (for efficiency).

     * <p> This method may be used to enable access to all reflected objects in

     * the array when access to each reflected object can be enabled as

     * specified by {@link #setAccessible(boolean) setAccessible(boolean)}. </p>

     * @throws InaccessibleObjectException if access cannot be enabled for all

     *         objects in the array

     * @throws SecurityException if the request is denied by the security manager

     *         or an element in the array is a constructor for {@code

     *         java.lang.Class}

     * @revised 9

     * @spec JPMS

     * Set the {@code accessible} flag for this reflected object to

     * the reflected object should suppress checks for Java language access

     * control when it is used. A value of {@code false} indicates that

     * the reflected object should enforce checks for Java language access

     * control when it is used, with the variation noted in the class description.

     *

     * <p> This method may be used by a caller in class {@code C} to enable

     * access to a {@link Member member} of {@link Member#getDeclaringClass()

     * declaring class} {@code D} if any of the following hold: </p>

     *

     * <ul>

     *     <li> {@code C} and {@code D} are in the same module. </li>

     *

     *     <li> The member is {@code public} and {@code D} is {@code public} in

     *     a package that the module containing {@code D} {@link

     *     Module#isExported(String,Module) exports} to at least the module

     *     containing {@code C}. </li>

     *     <li> The member is {@code protected} {@code static}, {@code D} is

     *     {@code public} in a package that the module containing {@code D}

     *     exports to at least the module containing {@code C}, and {@code C}

     *     is a subclass of {@code D}. </li>

     *     <li> {@code D} is in a package that the module containing {@code D}

     *     {@link Module#isOpen(String,Module) opens} to at least the module

     *     containing {@code C}.

     *     All packages in unnamed and open modules are open to all modules and

     *     so this method always succeeds when {@code D} is in an unnamed or

     *     open module. </li>

     * </ul>

     *

     * <p> This method cannot be used to enable access to private members,

     * members with default (package) access, protected instance members, or

     * protected constructors when the declaring class is in a different module

     * to the caller and the package containing the declaring class is not open

     * to the caller's module. </p>

     *

     * <p> If there is a security manager, its

     * @throws SecurityException if the request is denied by the security manager

     * @see #trySetAccessible

     * @revised 9

     * @spec JPMS

    /**

     * Sets the accessible flag and returns the new value

     */

    boolean setAccessible0(boolean flag) {

        return flag;

    /**

     * Set the {@code accessible} flag for this reflected object to {@code true}

     * if possible. This method sets the {@code accessible} flag, as if by

     * invoking {@link #setAccessible(boolean) setAccessible(true)}, and returns

     * the possibly-updated value for the {@code accessible} flag. If access

     * cannot be enabled, i.e. the checks or Java language access control cannot

     * be suppressed, this method returns {@code false} (as opposed to {@code

     * setAccessible(true)} throwing {@code InaccessibleObjectException} when

     * it fails).

     *

     * <p> This method is a no-op if the {@code accessible} flag for

     * this reflected object is {@code true}.

     *

     * <p> For example, a caller can invoke {@code trySetAccessible}

     * on a {@code Method} object for a private instance method

     * {@code p.T::privateMethod} to suppress the checks for Java language access

     * control when the {@code Method} is invoked.

     * If {@code p.T} class is in a different module to the caller and

     * package {@code p} is open to at least the caller's module,

     * the code below successfully sets the {@code accessible} flag

     * to {@code true}.

     *

     * <pre>

     * {@code

     *     p.T obj = ....;  // instance of p.T

     *     :

     *     Method m = p.T.class.getDeclaredMethod("privateMethod");

     *     if (m.trySetAccessible()) {

     *         m.invoke(obj);

     *     } else {

     *         // package p is not opened to the caller to access private member of T

     *         ...

     *     }

     * }</pre>

     *

     * <p> If there is a security manager, its {@code checkPermission} method

     * is first called with a {@code ReflectPermission("suppressAccessChecks")}

     * permission. </p>

     *

     * @return {@code true} if the {@code accessible} flag is set to {@code true};

     *         {@code false} if access cannot be enabled.

     * @throws SecurityException if the request is denied by the security manager

     *

     * @since 9

     * @spec JPMS

     * @see java.lang.invoke.MethodHandles#privateLookupIn

     */

    @CallerSensitive

    public final boolean trySetAccessible() {

        AccessibleObject.checkPermission();

        if (override == true) return true;

        // if it's not a Constructor, Method, Field then no access check

        if (!Member.class.isInstance(this)) {

            return setAccessible0(true);

        }

        // does not allow to suppress access check for Class's constructor

        Class<?> declaringClass = ((Member) this).getDeclaringClass();

        if (declaringClass == Class.class && this instanceof Constructor) {

            return false;

        }

        if (checkCanSetAccessible(Reflection.getCallerClass(),

                                  declaringClass,

                                  false)) {

            return setAccessible0(true);

        } else {

            return false;

        }

    }

        checkCanSetAccessible(caller, declaringClass, true);

    }

    private boolean checkCanSetAccessible(Class<?> caller,

                                          Class<?> declaringClass,

                                          boolean throwExceptionIfDenied) {

        if (callerModule == declaringModule) return true;

        if (callerModule == Object.class.getModule()) return true;

        if (!declaringModule.isNamed()) return true;

            dumpStackIfOpenedReflectively(declaringModule, pn, callerModule);

            return true;

        // package is exported to caller

        if (isExported && isClassPublic) {

            // member is public

            if (Modifier.isPublic(modifiers)) {

                dumpStackIfExportedReflectively(declaringModule, pn, callerModule);

                return true;

            }

            // member is protected-static

            if (Modifier.isProtected(modifiers)

                && Modifier.isStatic(modifiers)

                && isSubclassOf(caller, declaringClass)) {

                dumpStackIfExportedReflectively(declaringModule, pn, callerModule);

                return true;

            }

        if (throwExceptionIfDenied) {

            // not accessible

            String msg = "Unable to make ";

            if (this instanceof Field)

                msg += "field ";

            msg += this + " accessible: " + declaringModule + " does not \"";

            if (isClassPublic && Modifier.isPublic(modifiers))

                msg += "exports";

            else

                msg += "opens";

            msg += " " + pn + "\" to " + callerModule;

            InaccessibleObjectException e = new InaccessibleObjectException(msg);

            if (Reflection.printStackTraceWhenAccessFails()) {

                e.printStackTrace(System.err);

            }

            throw e;

        return false;

    private boolean isSubclassOf(Class<?> queryClass, Class<?> ofClass) {

        while (queryClass != null) {

            if (queryClass == ofClass) {

                return true;

            }

            queryClass = queryClass.getSuperclass();

        }

        return false;

    private void dumpStackIfOpenedReflectively(Module module,

                                               String pn,

                                               Module other) {

        dumpStackIfExposedReflectively(module, pn, other, true);

    private void dumpStackIfExportedReflectively(Module module,

                                                 String pn,

                                                 Module other) {

        dumpStackIfExposedReflectively(module, pn, other, false);

    }

    private void dumpStackIfExposedReflectively(Module module,

                                                String pn,

                                                Module other,

                                                boolean open)

                && !module.isStaticallyExportedOrOpen(pn, other, open))

     * Get the value of the {@code accessible} flag for this reflected object.

     *

     * @deprecated

     * This method is deprecated because its name hints that it checks

     * if the reflected object is accessible when it actually indicates

     * if the checks for Java language access control are suppressed.

     * This method may return {@code false} on a reflected object that is

     * accessible to the caller. To test if this reflected object is accessible,

     * it should use {@link #canAccess(Object)}.

     *

     * @revised 9

    @Deprecated(since="9")

     * Test if the caller can access this reflected object. If this reflected

     * object corresponds to an instance method or field then this method tests

     * if the caller can access the given {@code obj} with the reflected object.

     * For instance methods or fields then the {@code obj} argument must be an

     * instance of the {@link Member#getDeclaringClass() declaring class}. For

     * static members and constructors then {@code obj} must be {@code null}.

     *

     * <p> This method returns {@code true} if the {@code accessible} flag

     * is set to {@code true}, i.e. the checks for Java language access control

     * are suppressed, or if the caller can access the member as

     * specified in <cite>The Java&trade; Language Specification</cite>,

     * with the variation noted in the class description. </p>

     *

     * @param obj an instance object of the declaring class of this reflected

     *            object if it is an instance method or field

     *

     * @return {@code true} if the caller can access this reflected object.

     *

     * @throws IllegalArgumentException

     *         <ul>

     *         <li> if this reflected object is a static member or constructor and

     *              the given {@code obj} is non-{@code null}, or </li>

     *         <li> if this reflected object is an instance method or field

     *              and the given {@code obj} is {@code null} or of type

     *              that is not a subclass of the {@link Member#getDeclaringClass()

     *              declaring class} of the member.</li>

     *         </ul>

     *

     * @since 9

     * @spec JPMS

     * @jls 6.6 Access Control

     * @see #trySetAccessible

     * @see #setAccessible(boolean)

     */

    @CallerSensitive

    public final boolean canAccess(Object obj) {

        if (!Member.class.isInstance(this)) {

            return override;

        }

        Class<?> declaringClass = ((Member) this).getDeclaringClass();

        int modifiers = ((Member) this).getModifiers();

        if (!Modifier.isStatic(modifiers) &&

                (this instanceof Method || this instanceof Field)) {

            if (obj == null) {

                throw new IllegalArgumentException("null object for " + this);

            }

            // if this object is an instance member, the given object

            // must be a subclass of the declaring class of this reflected object

            if (!declaringClass.isAssignableFrom(obj.getClass())) {

                throw new IllegalArgumentException("object is not an instance of "

                                                   + declaringClass.getName());

            }

        } else if (obj != null) {

            throw new IllegalArgumentException("non-null object for " + this);

        }

        // access check is suppressed

        if (override) return true;

        Class<?> caller = Reflection.getCallerClass();

        Class<?> targetClass;

        if (this instanceof Constructor) {

            targetClass = declaringClass;

        } else {

            targetClass = Modifier.isStatic(modifiers) ? null : obj.getClass();

        }

        return Reflection.verifyMemberAccess(caller,

                                             declaringClass,

                                             targetClass,

                                             modifiers);

    }

    /**